List 55

cells

Start learning with an activity...

  • Practice

    Answer a few questions on each word. Get one wrong? We'll ask some follow-up questions. Use it to prep for your next quiz!

  • Spelling Bee

    Test your spelling acumen. See the definition, listen to the word, then try to spell it correctly. Beat your last streak, or best your overall time. Spellers of the world, untie!

  • Vocabulary Jam

    Compete head-to-head in real-time to see which team can answer the most questions correctly. Start a Jam and invite your friends and classmates to join!

Explore the Words


definitions & notes
only words

  1. microtubule

    a microscopically small tubule
    Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes

    Typical organisms bacteria, archaea protists, fungi, plants, animals

    Typical size ~ 1–10 µm ~ 10–100 µm (sperm cells, apart from the tail, are smaller)

    Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane

    DNA circular (usually) linear molecules (chromosomes) with histone proteins

    RNA-/protein-synthesis coupled in cytoplasm RNA-synthesis inside the nucleus

    prot...
  2. Krebs cycle

    in all plants and animals, a series of enzymatic reactions in mitochondria involving oxidative metabolism of acetyl compounds to produce high-energy phosphate compounds that are the source of cellular energy
    The second pathway, called the
    Krebs cycle, or citric acid cycle, occurs inside the mitochondria and can generate enough ATP to run all the cell functions.
  3. diploid

    an organism or cell having the normal amount of DNA per cell
    A
    diploid cell may also undergo meiosis to produce haploid cells, usually four.
  4. cytokinesis

    organic process consisting of the division of the cytoplasm of a cell following karyokinesis bringing about the separation into two daughter cells
    Cell imaged on a fluorescent microscope.The cytoskeleton acts to organize and maintain the cell's shape; anchors organelles in place; helps during endocytosis, the uptake of external materials by a cell, and
    cytokinesis, the separation of daughter cells after cell division; and moves parts of the cell in processes of growth and mobility.
  5. cyanobacteria

    predominantly photosynthetic prokaryotic organisms containing a blue pigment in addition to chlorophyll; occur singly or in colonies in diverse habitats; important as phytoplankton
    DNA-bearing organelles like the mitochondria and the chloroplasts are almost certainly what remains of ancient symbiotic oxygen-breathing proteobacteria and
    cyanobacteria, respectively, where the rest of the cell seems to be derived from an ancestral archaean prokaryote cell – a theory termed the endosymbiotic theory.
  6. cytolysis

    pathological breakdown of cells by the destruction of their outer membrane
    It also prevents the cell from expanding and finally bursting (
    cytolysis) from osmotic pressure against a hypotonic environment.
  7. centriole

    one of a pair of small cylindrical cell organelles near the nucleus in animal cells; composed of nine triplet microtubules and form the asters during mitosis
    Organelles:

    (1) nucleolus

    (2) nucleus

    (3) ribosome

    (4) vesicle

    (5) rough endoplasmic reticulum (ER)

    (6) Golgi apparatus

    (7) Cytoskeleton

    (8) smooth endoplasmic reticulum

    (9) mitochondria

    (10) vacuole

    (11) cytoplasm

    (12) lysosome

    (13)
    centrioles within centrosomeEukaryotic cells are about 15 times wider than a typical prokaryote and can be as much as 1000 times greater in volume.
  8. eukaryotic

    having cells with `good' or membrane-bound nuclei
    Anatomy

    There are two types of cells:
    eukaryotic and prokaryotic.
  9. heterotroph

    an organism that feeds on complex organic substances
    The current belief is that these cells were
    heterotrophs.
  10. citric acid cycle

    in all plants and animals, a series of enzymatic reactions in mitochondria of involving oxidative metabolism of acetyl compounds to produce high-energy phosphate compounds that are the source of cellular energy
    The second pathway, called the Krebs cycle, or
    citric acid cycle, occurs inside the mitochondria and can generate enough ATP to run all the cell functions.
  11. plasma membrane

    a thin membrane enclosing the cytoplasm of a cell
    These are structures (not present in all prokaryotes) made of proteins that facilitate movement and communication between cells;

    Enclosing the cell is the cell envelope – generally consisting of a cell wall covering a
    plasma membrane though some bacteria also have a further covering layer called a capsule.
  12. cytosol

    the aqueous part of the cytoplasm within which various particles and organelles are suspended
    The
    cytosol is the gelatinous fluid that fills the cell and surrounds the organelles.
  13. cytoskeleton

    a microscopic network of actin filaments and microtubules in the cytoplasm of many living cells that gives the cell shape and coherence
    Organelles:

    (1) nucleolus

    (2) nucleus

    (3) ribosome

    (4) vesicle

    (5) rough endoplasmic reticulum (ER)

    (6) Golgi apparatus

    (7)
    Cytoskeleton

    (8) smooth endoplasmic reticulum

    (9) mitochondria

    (10) vacuole

    (11) cytoplasm

    (12) lysosome

    (13) centrioles within centrosomeEukaryotic cells are about 15 times wider than a typical prokaryote and can be as much as 1000 times greater in volume.
  14. Golgi apparatus

    a netlike structure in the cytoplasm of animal cells
    Organelles:

    (1) nucleolus

    (2) nucleus

    (3) ribosome

    (4) vesicle

    (5) rough endoplasmic reticulum (ER)

    (6)
    Golgi apparatus

    (7) Cytoskeleton

    (8) smooth endoplasmic reticulum

    (9) mitochondria

    (10) vacuole

    (11) cytoplasm

    (12) lysosome

    (13) centrioles within centrosomeEukaryotic cells are about 15 times wider than a typical prokaryote and can be as much as 1000 times greater in volume.
  15. prokaryote

    a unicellular organism lacking a membrane-bound nucleus
    Prokaryotic cells

    Main article:
    Prokaryote

    Diagram of a typical prokaryotic cellThe prokaryote cell is simpler, and therefore smaller, than a eukaryote cell, lacking a nucleus and most of the other organelles of eukaryotes.

  16. hypotonic

    (of living tissue) lacking normal tone or tension
    It also prevents the cell from expanding and finally bursting (cytolysis) from osmotic pressure against a
    hypotonic environment.
  17. cell organelle

    a specialized part of a cell; analogous to an organ
    Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes

    Typical organisms bacteria, archaea protists, fungi, plants, animals

    Typical size ~ 1–10 µm ~ 10–100 µm (sperm cells, apart from the tail, are smaller)

    Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane

    DNA circular (usually) linear molecules (chromosomes) with histone proteins

    RNA-/protein-synthesis coupled in cytoplasm RNA-synthesis inside the nucleus

    prot...
  18. prokaryotic

    having cells that lack membrane-bound nuclei
    Anatomy

    There are two types of cells: eukaryotic and
    prokaryotic.
  19. eukaryote

    an organism of one or more cells with membrane-bound nuclei
    Prokaryotic cells

    Main article: Prokaryote

    Diagram of a typical prokaryotic cellThe prokaryote cell is simpler, and therefore smaller, than a
    eukaryote cell, lacking a nucleus and most of the other organelles of eukaryotes.

  20. organelle

    a specialized part of a cell; analogous to an organ
    Prokaryotic cells

    Main article: Prokaryote

    Diagram of a typical prokaryotic cellThe prokaryote cell is simpler, and therefore smaller, than a eukaryote cell, lacking a nucleus and most of the other
    organelles of eukaryotes.

  21. mRNA

    the template for protein synthesis
    RNA is also used for information transport (e.g.,
    mRNA) and enzymatic functions (e.g., ribosomal RNA) in organisms that use DNA for the genetic code itself.
  22. ribosome

    a particle in a cell that helps synthesize proteins
    Some eukaryote cells (plant cells and fungi cells) also have a cell wall;

    Inside the cell is the cytoplasmic region that contains the cell genome (DNA) and
    ribosomes and various sorts of inclusions.
  23. Golgi

    Italian histologist noted for work on the structure of the nervous system and for his discovery of Golgi bodies (1844-1926)
    Organelles:

    (1) nucleolus

    (2) nucleus

    (3) ribosome

    (4) vesicle

    (5) rough endoplasmic reticulum (ER)

    (6)
    Golgi apparatus

    (7) Cytoskeleton

    (8) smooth endoplasmic reticulum

    (9) mitochondria

    (10) vacuole

    (11) cytoplasm

    (12) lysosome

    (13) centrioles within centrosomeEukaryotic cells are about 15 times wider than a typical prokaryote and can be as much as 1000 times greater in volume.
  24. mitochondrion

    an organelle containing enzymes responsible for producing energy
    Organelles:

    (1) nucleolus

    (2) nucleus

    (3) ribosome

    (4) vesicle

    (5) rough endoplasmic reticulum (ER)

    (6) Golgi apparatus

    (7) Cytoskeleton

    (8) smooth endoplasmic reticulum

    (9)
    mitochondria

    (10) vacuole

    (11) cytoplasm

    (12) lysosome

    (13) centrioles within centrosomeEukaryotic cells are about 15 times wider than a typical prokaryote and can be as much as 1000 times greater in volume.
  25. cytoplasm

    the substance inside a cell, not including the nucleus
    Nuclear material of prokaryotic cell consist of a single chromosome which is in direct contact with
    cytoplasm.
  26. haploid

    (genetics) an organism or cell having only one complete set of chromosomes
    A diploid cell may also undergo meiosis to produce
    haploid cells, usually four.
  27. tRNA

    RNA molecules present in the cell (in at least 20 varieties, each variety capable of combining with a specific amino acid) that attach the correct amino acid to the protein chain that is being synthesized at the ribosome of the cell (according to directions coded in the mRNA)
    Transfer RNA (
    tRNA) molecules are used to add amino acids during protein translation.
  28. RNA

    (biochemistry) a long linear polymer of nucleotides found in the nucleus but mainly in the cytoplasm of a cell where it is associated with microsomes; it transmits genetic information from DNA to the cytoplasm and controls certain chemical processes in the cell
    Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes

    Typical organisms bacteria, archaea protists, fungi, plants, animals

    Typical size ~ 1–10 µm ~ 10–100 µm (sperm cells, apart from the tail, are smaller)

    Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane

    DNA circular (usually) linear molecules (chromosomes) with histone proteins


    RNA-/protein-synthesis coupled in cytoplasm RNA-synthesis inside the nucleu...
  29. lysosome

    an organelle found in the cytoplasm of most cells
    Organelles:

    (1) nucleolus

    (2) nucleus

    (3) ribosome

    (4) vesicle

    (5) rough endoplasmic reticulum (ER)

    (6) Golgi apparatus

    (7) Cytoskeleton

    (8) smooth endoplasmic reticulum

    (9) mitochondria

    (10) vacuole

    (11) cytoplasm

    (12)
    lysosome

    (13) centrioles within centrosomeEukaryotic cells are about 15 times wider than a typical prokaryote and can be as much as 1000 times greater in volume.
  30. polypeptide

    a peptide containing 10 to more than 100 amino acids
    The capsule may be polysaccharide as in pneumococci, meningococci or
    polypeptide as Bacillus anthracis or hyaluronic acid as in streptococci.[citation needed] Capsules are not marked by ordinary stain and can be detected by special stain.
  31. cell nucleus

    a part of the cell containing DNA and RNA and responsible for growth and reproduction
    Most important among these is a
    cell nucleus, a membrane-delineated compartment that houses the eukaryotic cell's DNA. This nucleus gives the eukaryote its name, which means "true nucleus."
  32. reticulum

    any fine network
    Organelles:

    (1) nucleolus

    (2) nucleus

    (3) ribosome

    (4) vesicle

    (5) rough endoplasmic
    reticulum (ER)

    (6) Golgi apparatus

    (7) Cytoskeleton

    (8) smooth endoplasmic reticulum

    (9) mitochondria

    (10) vacuole

    (11) cytoplasm

    (12) lysosome

    (13) centrioles within centrosomeEukaryotic cells are about 15 times wider than a typical prokaryote and can be as much as 1000 times greater in volume.
  33. glycolysis

    a metabolic process that breaks down carbohydrates and sugars through a series of reactions to either pyruvic acid or lactic acid and releases energy for the body in the form of ATP
    The first pathway,
    glycolysis, requires no oxygen and is referred to as anaerobic metabolism.
  34. histone

    a simple protein containing mainly basic amino acids
    The eukaryotic DNA is organized in one or more linear molecules, called chromosomes, which are associated with
    histone proteins.
  35. plastid

    any of various small particles in the cytoplasm of the cells of plants and some animals containing pigments or starch or oil or protein
    Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes

    Typical organisms bacteria, archaea protists, fungi, plants, animals

    Typical size ~ 1–10 µm ~ 10–100 µm (sperm cells, apart from the tail, are smaller)

    Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane

    DNA circular (usually) linear molecules (chromosomes) with histone proteins

    RNA-/protein-synthesis coupled in cytoplasm RNA-synthesis inside the nucleus

    prot...
  36. mitosis

    the process by which a cell divides into two smaller cells
    Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes

    Typical organisms bacteria, archaea protists, fungi, plants, animals

    Typical size ~ 1–10 µm ~ 10–100 µm (sperm cells, apart from the tail, are smaller)

    Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane

    DNA circular (usually) linear molecules (chromosomes) with histone proteins

    RNA-/protein-synthesis coupled in cytoplasm RNA-synthesis inside the nucleus

    prot...
  37. biosynthesis

    production of a chemical compound by a living organism
    Protein synthesis

    Main article: Protein
    biosynthesis

    Cells are capable of synthesizing new proteins, which are essential for the modulation and maintenance of cellular activities.
  38. mitotic

    of or relating to or undergoing mitosis
    Centrosomes are composed of two centrioles, which separate during cell division and help in the formation of the
    mitotic spindle.
  39. meiosis

    cell division in sexually reproducing organisms
    Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes

    Typical organisms bacteria, archaea protists, fungi, plants, animals

    Typical size ~ 1–10 µm ~ 10–100 µm (sperm cells, apart from the tail, are smaller)

    Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane

    DNA circular (usually) linear molecules (chromosomes) with histone proteins

    RNA-/protein-synthesis coupled in cytoplasm RNA-synthesis inside the nucleus

    prot...
  40. cell

    the basic structural and functional unit of all organisms
    Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word "
    cell" being used to describe the smallest unit of a living organism

    Cells in culture, stained for keratin (red) and DNA (green)The cell is the functional basic unit of life.
  41. ATP

    a nucleotide derived from adenosine that occurs in muscle tissue; the major source of energy for cellular reactions
    Mitochondria generate the cell's energy by oxidative phosphorylation, using oxygen to release energy stored in cellular nutrients (typically pertaining to glucose) to generate
    ATP. Mitochondria multiply by splitting in two.
  42. transfer RNA

    RNA molecules present in the cell (in at least 20 varieties, each variety capable of combining with a specific amino acid) that attach the correct amino acid to the protein chain that is being synthesized at the ribosome of the cell (according to directions coded in the mRNA)
    Transfer RNA (tRNA) molecules are used to add amino acids during protein translation.
  43. cell membrane

    a thin membrane enclosing the cytoplasm of a cell
    Membrane

    Main article:
    Cell membrane

    The cytoplasm of a cell is surrounded by a cell membrane or plasma membrane.
  44. codon

    a specific sequence of three adjacent nucleotides on a strand of DNA or RNA that specifies the genetic code information for synthesizing a particular amino acid
    Within the nucleus of the cell (light blue), genes (DNA, dark blue) are transcribed into RNA. This RNA is then subject to post-transcriptional modification and control, resulting in a mature mRNA (red) that is then transported out of the nucleus and into the cytoplasm (peach), where it undergoes translation into a protein. mRNA is translated by ribosomes (purple) that match the three-base
    codons of the mRNA to the three-base anti-codons of the appropriate tRNA.
  45. cell wall

    a rigid layer of polysaccharides enclosing a plant membrane
    These are structures (not present in all prokaryotes) made of proteins that facilitate movement and communication between cells;

    Enclosing the cell is the cell envelope – generally consisting of a
    cell wall covering a plasma membrane though some bacteria also have a further covering layer called a capsule.
  46. multicellular

    consisting of many basic structural and functional units
    Other organisms, such as humans, are
    multicellular.
  47. borrelia

    cause of e.g. European and African relapsing fever
    A prokaryotic chromosome is usually a circular molecule (an exception is that of the bacterium
    Borrelia burgdorferi, which causes Lyme disease).
  48. Borrelia burgdorferi

    cause of Lyme disease
    A prokaryotic chromosome is usually a circular molecule (an exception is that of the bacterium
    Borrelia burgdorferi, which causes Lyme disease).
  49. vacuole

    a tiny cavity filled with fluid in the cytoplasm of a cell
    Organelles:

    (1) nucleolus

    (2) nucleus

    (3) ribosome

    (4) vesicle

    (5) rough endoplasmic reticulum (ER)

    (6) Golgi apparatus

    (7) Cytoskeleton

    (8) smooth endoplasmic reticulum

    (9) mitochondria

    (10)
    vacuole

    (11) cytoplasm

    (12) lysosome

    (13) centrioles within centrosomeEukaryotic cells are about 15 times wider than a typical prokaryote and can be as much as 1000 times greater in volume.
  50. chloroplast

    plastid containing chlorophyll and other pigments
    Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes

    Typical organisms bacteria, archaea protists, fungi, plants, animals

    Typical size ~ 1–10 µm ~ 10–100 µm (sperm cells, apart from the tail, are smaller)

    Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane

    DNA circular (usually) linear molecules (chromosomes) with histone proteins

    RNA-/protein-synthesis coupled in cytoplasm RNA-synthesis inside the nucleus

    prot...
  51. lipid

    an oily organic compound insoluble in water but soluble in organic solvents; essential structural component of living cells (along with proteins and carbohydrates)
    This membrane serves to separate and protect a cell from its surrounding environment and is made mostly from a double layer of
    lipids (hydrophobic fat-like molecules) and hydrophilic phosphorus molecules.
  52. antigenic

    of or relating to antigens
    The capsule is
    antigenic.
  53. DNA

    a long linear polymer found in the nucleus of a cell
    Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word "cell" being used to describe the smallest unit of a living organism

    Cells in culture, stained for keratin (red) and
    DNA (green)The cell is the functional basic unit of life.
  54. protein molecule

    any large molecule containing chains of amino acids linked by peptide bonds
    Embedded within this membrane is a variety of
    protein molecules that act as channels and pumps that move different molecules into and out of the cell.
  55. phospholipid

    any of various compounds composed of fatty acids and phosphoric acid and a nitrogenous base; an important constituent of membranes
    Hence, the layer is called a
    phospholipid bilayer.
  56. cell theory

    (biology) the theory that cells form the fundamental structural and functional units of all living organisms; proposed in 1838 by Matthias Schleiden and by Theodor Schwann
    In 1835, before the final
    cell theory was developed, Jan Evangelista Purkyně observed small "granules" while looking at the plant tissue through a microscope.
  57. hydrophilic

    having a strong affinity for water
    This membrane serves to separate and protect a cell from its surrounding environment and is made mostly from a double layer of lipids (hydrophobic fat-like molecules) and
    hydrophilic phosphorus molecules.
  58. Theodor Schwann

    German physiologist and histologist who in 1838 and 1839 identified the cell as the basic structure of plant and animal tissue (1810-1882)
    The cell theory, first developed in 1839 by Matthias Jakob Schleiden and
    Theodor Schwann, states that all organisms are composed of one or more cells, that all cells come from preexisting cells, that vital functions of an organism occur within cells, and that all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.[5]
  59. adenosine triphosphate

    a nucleotide derived from adenosine that occurs in muscle tissue; the major source of energy for cellular reactions
    Once inside the cell, glucose is broken down to make
    adenosine triphosphate (ATP), a form of energy, through two different pathways.
  60. enzymatic

    of or relating to or produced by an enzyme
    RNA is also used for information transport (e.g., mRNA) and
    enzymatic functions (e.g., ribosomal RNA) in organisms that use DNA for the genetic code itself.
  61. cell division

    the process in reproduction and growth by which a cell divides to form daughter cells
    Cilia may thus be "viewed as sensory cellular antennae that coordinate a large number of cellular signaling pathways, sometimes coupling the signaling to ciliary motility or alternatively to
    cell division and differentiation."[7]
  62. centrosome

    small region of cytoplasm adjacent to the nucleus
    Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes

    Typical organisms bacteria, archaea protists, fungi, plants, animals

    Typical size ~ 1–10 µm ~ 10–100 µm (sperm cells, apart from the tail, are smaller)

    Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane

    DNA circular (usually) linear molecules (chromosomes) with histone proteins

    RNA-/protein-synthesis coupled in cytoplasm RNA-synthesis inside the nucleus

    prot...
  63. genome

    the full DNA sequence of an organism
    Some eukaryote cells (plant cells and fungi cells) also have a cell wall;

    Inside the cell is the cytoplasmic region that contains the cell
    genome (DNA) and ribosomes and various sorts of inclusions.
  64. nucleolus

    a small round body of protein in a cell nucleus
    Organelles:

    (1)
    nucleolus

    (2) nucleus

    (3) ribosome

    (4) vesicle

    (5) rough endoplasmic reticulum (ER)

    (6) Golgi apparatus

    (7) Cytoskeleton

    (8) smooth endoplasmic reticulum

    (9) mitochondria

    (10) vacuole

    (11) cytoplasm

    (12) lysosome

    (13) centrioles within centrosomeEukaryotic cells are about 15 times wider than a typical prokaryote and can be as much as 1000 times greater in volume.
  65. protein

    an organic compound essential to living cells
    These are structures (not present in all prokaryotes) made of
    proteins that facilitate movement and communication between cells;

    Enclosing the cell is the cell envelope – generally consisting of a cell wall covering a plasma membrane though some bacteria also have a further covering layer called a capsule.
  66. molecule

    the simplest structural unit of an element or compound
    A prokaryotic chromosome is usually a circular
    molecule (an exception is that of the bacterium Borrelia burgdorferi, which causes Lyme disease).
  67. oxidative

    taking place in the presence of oxygen
    Mitochondria generate the cell's energy by
    oxidative phosphorylation, using oxygen to release energy stored in cellular nutrients (typically pertaining to glucose) to generate ATP. Mitochondria multiply by splitting in two.
  68. messenger RNA

    the template for protein synthesis
    During processing, DNA is transcribed, or copied into a special RNA, called
    messenger RNA (mRNA).
  69. osmotic pressure

    (physical chemistry) the pressure exerted by a solution necessary to prevent osmosis into that solution when it is separated from the pure solvent by a semipermeable membrane
    It also prevents the cell from expanding and finally bursting (cytolysis) from
    osmotic pressure against a hypotonic environment.
  70. cytoplasmic

    of or relating to cytoplasm
    Some eukaryote cells (plant cells and fungi cells) also have a cell wall;

    Inside the cell is the
    cytoplasmic region that contains the cell genome (DNA) and ribosomes and various sorts of inclusions.
  71. motility

    ability to move spontaneously and independently
    Cilia may thus be "viewed as sensory cellular antennae that coordinate a large number of cellular signaling pathways, sometimes coupling the signaling to ciliary
    motility or alternatively to cell division and differentiation."[7]
  72. plasmid

    a small cellular inclusion consisting of a ring of DNA that is not in a chromosome but is capable of autonomous replication
    Prokaryotes can carry extrachromosomal DNA elements called
    plasmids, which are usually circular.
  73. flagellum

    a lash-like appendage used for locomotion
    A prokaryotic cell has three architectural regions:

    On the outside,
    flagella and pili project from the cell's surface.

  74. macromolecule

    any very large complex molecule
    Golgi apparatus – eukaryotes only

    The primary function of the Golgi apparatus is to process and package the
    macromolecules such as proteins and lipids that are synthesized by the cell.
  75. anterior horn

    one of two the two roots of a spinal nerve that passes ventrally from the spinal cord and that consists of motor fibers
    The largest cells are about 135 µm in the
    anterior horn in the spinal cord while granule cells in the cerebellum, the smallest, can be some 4 µm and the longest cell can reach from the toe to the lower brain stem (Pseudounipolar cells).[2]
  76. protist

    free-living or colonial organisms with diverse nutritional and reproductive modes
    Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes

    Typical organisms bacteria, archaea
    protists, fungi, plants, animals

    Typical size ~ 1–10 µm ~ 10–100 µm (sperm cells, apart from the tail, are smaller)

    Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane

    DNA circular (usually) linear molecules (chromosomes) with histone proteins

    RNA-/protein-synthesis coupled in cytoplasm RNA-synthesis inside the nucleu...
  77. catabolism

    breakdown in living organisms of more complex substances into simpler ones together with release of energy
    Metabolism has two distinct divisions:
    catabolism, in which the cell breaks down complex molecules to produce energy and reducing power, and anabolism, in which the cell uses energy and reducing power to construct complex molecules and perform other biological functions.
  78. membrane

    a sheet of tissue that lines or connects organs or cells
    These are structures (not present in all prokaryotes) made of proteins that facilitate movement and communication between cells;

    Enclosing the cell is the cell envelope – generally consisting of a cell wall covering a plasma
    membrane though some bacteria also have a further covering layer called a capsule.
  79. nucleus

    a part of the cell responsible for growth and reproduction
    Prokaryotic cells

    Main article: Prokaryote

    Diagram of a typical prokaryotic cellThe prokaryote cell is simpler, and therefore smaller, than a eukaryote cell, lacking a
    nucleus and most of the other organelles of eukaryotes.

  80. plant cell

    a cell that is a structural and functional unit of a plant
    Some eukaryote cells (
    plant cells and fungi cells) also have a cell wall;

    Inside the cell is the cytoplasmic region that contains the cell genome (DNA) and ribosomes and various sorts of inclusions.
  81. daughter cell

    a cell formed by the division or budding of another cell
    Cell imaged on a fluorescent microscope.The cytoskeleton acts to organize and maintain the cell's shape; anchors organelles in place; helps during endocytosis, the uptake of external materials by a cell, and cytokinesis, the separation of
    daughter cells after cell division; and moves parts of the cell in processes of growth and mobility.
  82. Bacillus anthracis

    a species of bacillus that causes anthrax in humans and in animals (cattle and swine and sheep and rabbits and mice and guinea pigs); can be used a bioweapon
    The capsule may be polysaccharide as in pneumococci, meningococci or polypeptide as
    Bacillus anthracis or hyaluronic acid as in streptococci.[citation needed] Capsules are not marked by ordinary stain and can be detected by special stain.
  83. hyaluronic acid

    a viscous mucopolysaccharide found in the connective tissue space and the synovial fluid of movable joints and the humors of the eye; a cementing and protective substance
    The capsule may be polysaccharide as in pneumococci, meningococci or polypeptide as Bacillus anthracis or
    hyaluronic acid as in streptococci.[citation needed] Capsules are not marked by ordinary stain and can be detected by special stain.
  84. synthesize

    combine and form a complex whole
    Golgi apparatus – eukaryotes only

    The primary function of the Golgi apparatus is to process and package the macromolecules such as proteins and lipids that are
    synthesized by the cell.
  85. effector

    one who brings about a result or event
    Newly synthesized proteins (black) are often further modified, such as by binding to an
    effector molecule (orange), to become fully active.Creation
  86. permeable

    allowing fluids or gases to pass or diffuse through
    Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes

    Typical organisms bacteria, archaea protists, fungi, plants, animals

    Typical size ~ 1–10 µm ~ 10–100 µm (sperm cells, apart from the tail, are smaller)

    Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane

    DNA circular (usually) linear molecules (chromosomes) with histone proteins

    RNA-/protein-synthesis coupled in cytoplasm RNA-synthesis inside the nucleus

    prot...
  87. chromosome

    a threadlike strand of DNA that carries genes
    Nuclear material of prokaryotic cell consist of a single
    chromosome which is in direct contact with cytoplasm.
  88. cilium

    a hairlike projection from the surface of a cell
    Some eukaryotic organelles such as mitochondria also contain some DNA.

    Many eukaryotic cells are ciliated with primary
    cilia.
  89. symbiotic

    of organisms living together, especially to mutual advantage
    Both organelles contain this DNA in circular plasmids, much like prokaryotic cells, strongly supporting the evolutionary theory of endosymbiosis; since these organelles contain their own genomes and have other similarities to prokaryotes, they are thought to have developed through a
    symbiotic relationship after being engulfed by a primitive cell.[citation needed]

    Endoplasmic reticulum – eukaryotes only

    The endoplasmic reticulum (ER) is the transport network for molecules targeted ...
  90. encode

    represent ordinary language in a secret form
    The biological information contained in an organism is
    encoded in its DNA or RNA sequence.
  91. accrete

    grow together (of plants and organs)
    An 'origin of sex as vaccination' theory suggests that the eukaryote genome
    accreted from prokaryan parasite genomes in numerous rounds of lateral gene transfer.
  92. polysaccharide

    any of a class of carbohydrates whose molecules contain chains of monosaccharide molecules
    The capsule may be
    polysaccharide as in pneumococci, meningococci or polypeptide as Bacillus anthracis or hyaluronic acid as in streptococci.[citation needed] Capsules are not marked by ordinary stain and can be detected by special stain.
  93. electric potential

    the difference in electrical charge between two points in a circuit expressed in volts
    Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes

    Typical organisms bacteria, archaea protists, fungi, plants, animals

    Typical size ~ 1–10 µm ~ 10–100 µm (sperm cells, apart from the tail, are smaller)

    Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane

    DNA circular (usually) linear molecules (chromosomes) with histone proteins

    RNA-/protein-synthesis coupled in cytoplasm RNA-synthesis inside the nucleus

    prot...
  94. vesicle

    a small anatomically normal sac or bladderlike structure
    Organelles:

    (1) nucleolus

    (2) nucleus

    (3) ribosome

    (4)
    vesicle

    (5) rough endoplasmic reticulum (ER)

    (6) Golgi apparatus

    (7) Cytoskeleton

    (8) smooth endoplasmic reticulum

    (9) mitochondria

    (10) vacuole

    (11) cytoplasm

    (12) lysosome

    (13) centrioles within centrosomeEukaryotic cells are about 15 times wider than a typical prokaryote and can be as much as 1000 times greater in volume.
  95. replication

    the act of making copies
    It houses the cell's chromosomes, and is the place where almost all DNA
    replication and RNA synthesis (transcription) occur.
  96. replicate

    reproduce or make an exact copy of
    Diagram of a cell nucleus

    Mitochondria and Chloroplasts – eukaryotes only - the power generators

    Mitochondria are self-
    replicating organelles that occur in various numbers, shapes, and sizes in the cytoplasm of all eukaryotic cells.
  97. mycoplasma

    any of a group of small parasitic bacteria that lack cell walls and can survive without oxygen; can cause pneumonia and urinary tract infection
    Though most prokaryotes have a cell wall, there are exceptions such as
    Mycoplasma (bacteria) and Thermoplasma (archaea).
  98. metabolism

    the organic processes that are necessary for life
    There are special types of pili called (sex pili) involved in conjunction.[citation needed]

    Functions

    Growth and
    metabolism

    Main articles: Cell growth and Metabolism

    Between successive cell divisions, cells grow through the functioning of cellular metabolism.

  99. keratin

    a fibrous scleroprotein that occurs in the outer layer of the skin and in horny tissues such as hair, feathers, nails, and hooves
    Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word "cell" being used to describe the smallest unit of a living organism

    Cells in culture, stained for
    keratin (red) and DNA (green)The cell is the functional basic unit of life.
  100. anabolism

    the synthesis in living organisms of more complex substances (e.g., living tissue) from simpler ones together with the storage of energy
    Metabolism has two distinct divisions: catabolism, in which the cell breaks down complex molecules to produce energy and reducing power, and
    anabolism, in which the cell uses energy and reducing power to construct complex molecules and perform other biological functions.
  101. adenosine

    a nucleoside that is a structural component of nucleic acids
    Once inside the cell, glucose is broken down to make
    adenosine triphosphate (ATP), a form of energy, through two different pathways.
  102. genetic

    relating to the study of heredity and variation in organisms
    Genetic material

    Two different kinds of genetic material exist: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
  103. catalyze

    change by catalysis or cause to catalyze
    RNA is generally assumed to be the earliest self-replicating molecule, as it is capable of both storing genetic information and
    catalyzing chemical reactions (see RNA world hypothesis).
  104. bacteria

    single-celled organisms that can cause disease
    Some organisms, such as most
    bacteria, are unicellular (consist of a single cell).
  105. ribonucleic acid

    (biochemistry) a long linear polymer of nucleotides found in the nucleus but mainly in the cytoplasm of a cell where it is associated with microsomes; it transmits genetic information from DNA to the cytoplasm and controls certain chemical processes in the cell
    Genetic material

    Two different kinds of genetic material exist: deoxyribonucleic acid (DNA) and
    ribonucleic acid (RNA).
  106. abiogenesis

    a hypothetical organic phenomenon by which living organisms are created from nonliving matter
    Origin of the first cell

    Further information:
    Abiogenesis

    There are several theories about the origin of small molecules that could lead to life in an early Earth.
  107. hydrophobic

    lacking affinity for water
    This membrane serves to separate and protect a cell from its surrounding environment and is made mostly from a double layer of lipids (
    hydrophobic fat-like molecules) and hydrophilic phosphorus molecules.
  108. hydrogen ion

    a positively charged atom of hydrogen
    Each reaction is designed to produce some
    hydrogen ions that can then be used to make energy packets (ATP).
  109. organism

    a living thing that can act or function independently
    Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word "cell" being used to describe the smallest unit of a living
    organism

    Cells in culture, stained for keratin (red) and DNA (green)The cell is the functional basic unit of life.
  110. gamete

    a mature sexual reproductive cell
    Haploid cells serve as
    gametes in multicellular organisms, fusing to form new diploid cells.
  111. Hooke

    English scientist who formulated the law of elasticity and proposed a wave theory of light and formulated a theory of planetary motion and proposed the inverse square law of gravitational attraction and discovered the cellular structure of cork and introduced the term `cell' into biology and invented a balance spring for watches (1635-1703)
    Drawing of the structure of cork as it appeared under the microscope to Robert
    Hooke from Micrographia which is the origin of the word "cell" being used to describe the smallest unit of a living organism

    Cells in culture, stained for keratin (red) and DNA (green)The cell is the functional basic unit of life.
  112. unicellular

    having a single basic functional unit, of an organism
    Some organisms, such as most bacteria, are
    unicellular (consist of a single cell).
  113. synthesis

    the combination of ideas into a complex whole
    Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes

    Typical organisms bacteria, archaea protists, fungi, plants, animals

    Typical size ~ 1–10 µm ~ 10–100 µm (sperm cells, apart from the tail, are smaller)

    Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane

    DNA circular (usually) linear molecules (chromosomes) with histone proteins

    RNA-/protein-
    synthesis coupled in cytoplasm RNA-synthesis inside the nucleu...
  114. amino acid

    organic compounds containing an amino group and acid group
    Transfer RNA (tRNA) molecules are used to add
    amino acids during protein translation.
  115. anaerobic

    not using or dependent on oxygen
    The first pathway, glycolysis, requires no oxygen and is referred to as
    anaerobic metabolism.
  116. fibroblast

    a cell from which connective tissue develops
    At the same time
    fibroblasts (connective tissue cells) move there to remodel damaged structures.
  117. peptide

    amide combining the amino group of one amino acid with the carboxyl group of another; usually obtained by partial hydrolysis of protein
    But some other entity with the potential to self-replicate could have preceded RNA, like clay or
    peptide nucleic acid.[13]
  118. motile

    capable of movement
    Eukaryotes can move using
    motile cilia or flagella.
  119. fimbria

    thin projections forming a fringe
    Fimbriae (pili)

    They are short and thin hair like filaments, formed of protein called pilin (antigenic).
  120. amino

    pertaining to or containing any of a group of organic compounds of nitrogen derived from ammonia
    Transfer RNA (tRNA) molecules are used to add
    amino acids during protein translation.
  121. cellular

    relating to cells
    Cilia may thus be "viewed as sensory
    cellular antennae that coordinate a large number of cellular signaling pathways, sometimes coupling the signaling to ciliary motility or alternatively to cell division and differentiation."[7]
  122. receptor

    a cellular structure that is postulated to exist in order to mediate between a chemical agent that acts on nervous tissue and the physiological response
    Cell surface membranes also contain
    receptor proteins that allow cells to detect external signaling molecules such as hormones.
  123. leading edge

    forward edge of an airfoil
    The process is divided into three steps – protrusion of the
    leading edge of the cell, adhesion of the leading edge and de-adhesion at the cell body and rear, and cytoskeletal contraction to pull the cell forward.
  124. deoxyribonucleic acid

    (biochemistry) a long linear polymer found in the nucleus of a cell and formed from nucleotides and shaped like a double helix; associated with the transmission of genetic information
    Genetic material

    Two different kinds of genetic material exist:
    deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
  125. plasma

    the watery fluid in which blood cells are suspended
    These are structures (not present in all prokaryotes) made of proteins that facilitate movement and communication between cells;

    Enclosing the cell is the cell envelope – generally consisting of a cell wall covering a
    plasma membrane though some bacteria also have a further covering layer called a capsule.
  126. brain stem

    the part of the brain continuous with the spinal cord and comprising the medulla oblongata and pons and midbrain and parts of the hypothalamus
    The largest cells are about 135 µm in the anterior horn in the spinal cord while granule cells in the cerebellum, the smallest, can be some 4 µm and the longest cell can reach from the toe to the lower
    brain stem (Pseudounipolar cells).[2]
  127. glucose

    a monosaccharide sugar that has several forms
    Mitochondria generate the cell's energy by oxidative phosphorylation, using oxygen to release energy stored in cellular nutrients (typically pertaining to
    glucose) to generate ATP. Mitochondria multiply by splitting in two.
  128. capsule

    a small container
    These are structures (not present in all prokaryotes) made of proteins that facilitate movement and communication between cells;

    Enclosing the cell is the cell envelope – generally consisting of a cell wall covering a plasma membrane though some bacteria also have a further covering layer called a
    capsule.
  129. chromosomal

    of or relating to a chromosome
    All
    chromosomal DNA is stored in the cell nucleus, separated from the cytoplasm by a membrane.
  130. archaean

    of or relating to the earliest known rocks formed during the Precambrian Eon
    DNA-bearing organelles like the mitochondria and the chloroplasts are almost certainly what remains of ancient symbiotic oxygen-breathing proteobacteria and cyanobacteria, respectively, where the rest of the cell seems to be derived from an ancestral
    archaean prokaryote cell – a theory termed the endosymbiotic theory.
  131. fission

    reproduction of a unicellular organism by cell division
    Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes

    Typical organisms bacteria, archaea protists, fungi, plants, animals

    Typical size ~ 1–10 µm ~ 10–100 µm (sperm cells, apart from the tail, are smaller)

    Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane

    DNA circular (usually) linear molecules (chromosomes) with histone proteins

    RNA-/protein-synthesis coupled in cytoplasm RNA-synthesis inside the nucleus

    prot...
  132. linear

    involving a single dimension
    The eukaryotic DNA is organized in one or more
    linear molecules, called chromosomes, which are associated with histone proteins.
  133. enzyme

    a complex protein produced by cells that acts as a catalyst
    All cells possess DNA, the hereditary material of genes, and RNA, containing the information necessary to build various proteins such as
    enzymes, the cell's primary machinery.
  134. mother cell

    cell from which another cell of an organism develops
    Main article: Cell division

    Cell division involves a single cell (called a
    mother cell) dividing into two daughter cells.
  135. pneumococcus

    bacterium causing pneumonia in mice and humans
    The capsule may be polysaccharide as in
    pneumococci, meningococci or polypeptide as Bacillus anthracis or hyaluronic acid as in streptococci.[citation needed] Capsules are not marked by ordinary stain and can be detected by special stain.
  136. retrovirus

    any of a group of viruses that contain two single-strand linear RNA molecules per virion and reverse transcriptase (RNA to DNA); the virus transcribes its RNA into a cDNA provirus that is then incorporated into the host cell
    Most organisms use DNA for their long-term information storage, but some viruses (e.g.,
    retroviruses) have RNA as their genetic material.
  137. uptake

    the process of taking food into the body through the mouth
    Cell imaged on a fluorescent microscope.The cytoskeleton acts to organize and maintain the cell's shape; anchors organelles in place; helps during endocytosis, the
    uptake of external materials by a cell, and cytokinesis, the separation of daughter cells after cell division; and moves parts of the cell in processes of growth and mobility.
  138. ciliary

    of or relating to cilia projecting from the surface of a cell
    Cilia may thus be "viewed as sensory cellular antennae that coordinate a large number of cellular signaling pathways, sometimes coupling the signaling to
    ciliary motility or alternatively to cell division and differentiation."[7]
  139. streptococci

    spherical Gram-positive bacteria occurring in pairs or chains; cause e.g. scarlet fever and tonsillitis
    The capsule may be polysaccharide as in pneumococci, meningococci or polypeptide as Bacillus anthracis or hyaluronic acid as in
    streptococci.[citation needed] Capsules are not marked by ordinary stain and can be detected by special stain.
  140. actin

    one of the proteins into which actomyosin can be split
    Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes

    Typical organisms bacteria, archaea protists, fungi, plants, animals

    Typical size ~ 1–10 µm ~ 10–100 µm (sperm cells, apart from the tail, are smaller)

    Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane

    DNA circular (usually) linear molecules (chromosomes) with histone proteins

    RNA-/protein-synthesis coupled in cytoplasm RNA-synthesis inside the nucleus

    prot...
  141. transcription

    something written, copied from one medium to another
    It houses the cell's chromosomes, and is the place where almost all DNA replication and RNA synthesis (
    transcription) occur.
  142. immune response

    a bodily defense reaction that recognizes an invading substance (an antigen: such as a virus or fungus or bacteria or transplanted organ) and produces antibodies specific against that antigen
    Movement or motility

    Cells can move during many processes: such as wound healing, the
    immune response and cancer metastasis.
  143. nucleic acid

    (biochemistry) any of various macromolecules composed of nucleotide chains that are vital constituents of all living cells
    But some other entity with the potential to self-replicate could have preceded RNA, like clay or peptide
    nucleic acid.[13]
  144. sperm cell

    the male reproductive cell; the male gamete
    Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes

    Typical organisms bacteria, archaea protists, fungi, plants, animals

    Typical size ~ 1–10 µm ~ 10–100 µm (
    sperm cells, apart from the tail, are smaller)

    Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane

    DNA circular (usually) linear molecules (chromosomes) with histone proteins

    RNA-/protein-synthesis coupled in cytoplasm RNA-synthesis inside the nucleu...
  145. binary

    of or pertaining to a number system having 2 as its base
    Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes

    Typical organisms bacteria, archaea protists, fungi, plants, animals

    Typical size ~ 1–10 µm ~ 10–100 µm (sperm cells, apart from the tail, are smaller)

    Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane

    DNA circular (usually) linear molecules (chromosomes) with histone proteins

    RNA-/protein-synthesis coupled in cytoplasm RNA-synthesis inside the nucleus

    prot...
  146. Lyme disease

    an acute inflammatory disease characterized by a rash with joint swelling and fever; caused by bacteria carried by the bite of a deer tick
    A prokaryotic chromosome is usually a circular molecule (an exception is that of the bacterium Borrelia burgdorferi, which causes
    Lyme disease).
  147. genetic code

    the ordering of nucleotides in DNA molecules that carries the genetic information in living cells
    RNA is also used for information transport (e.g., mRNA) and enzymatic functions (e.g., ribosomal RNA) in organisms that use DNA for the
    genetic code itself.
  148. photosynthesis

    formation of compounds in plants aided by radiant energy
    Organelles that are modified chloroplasts are broadly called plastids, and are involved in energy storage through
    photosynthesis, which uses solar energy to generate carbohydrates and oxygen from carbon dioxide and water.[citation needed]

    Mitochondria and chloroplasts each contain their own genome, which is separate and distinct from the nuclear genome of a cell.
  149. metastasis

    the spreading of a disease to another part of the body
    Movement or motility

    Cells can move during many processes: such as wound healing, the immune response and cancer
    metastasis.
  150. algae

    primitive chlorophyll-containing aquatic organisms
    Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes

    Typical organisms bacteria, archaea protists, fungi, plants, animals

    Typical size ~ 1–10 µm ~ 10–100 µm (sperm cells, apart from the tail, are smaller)

    Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane

    DNA circular (usually) linear molecules (chromosomes) with histone proteins

    RNA-/protein-synthesis coupled in cytoplasm RNA-synthesis inside the nucleus

    prot...
  151. citric acid

    a weak water-soluble acid found in many fruits
    The second pathway, called the Krebs cycle, or
    citric acid cycle, occurs inside the mitochondria and can generate enough ATP to run all the cell functions.
  152. Schwann

    German physiologist and histologist who in 1838 and 1839 identified the cell as the basic structure of plant and animal tissue (1810-1882)
    The cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor
    Schwann, states that all organisms are composed of one or more cells, that all cells come from preexisting cells, that vital functions of an organism occur within cells, and that all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.[5]
  153. adhesion

    the property of sticking together
    Cell motility involves many receptors, crosslinking, bundling, binding,
    adhesion, motor and other proteins.[10]
  154. egg cell

    the female reproductive cell; the female gamete
    The largest known cells are unfertilised ostrich
    egg cells which weigh 3.3 pounds.[3][4]
  155. meteorite

    a stony or metallic object from space that hits the earth
    One is that they came from
    meteorites (see Murchison meteorite).
  156. contractile

    capable of contracting or being contracted
    Some cells, most notably Amoeba, have
    contractile vacuoles, which can pump water out of the cell if there is too much water.
  157. catalytic

    relating to or causing or involving catalysis
    Lipids are known to spontaneously form bilayered vesicles in water, and could have preceded RNA. But the first cell membranes could also have been produced by
    catalytic RNA, or even have required structural proteins before they could form.[14]
  158. microorganism

    any organism of microscopic size
    For wound healing to occur, white blood cells and cells that ingest bacteria move to the wound site to kill the
    microorganisms that cause infection.
  159. pulmonary artery

    one of two arteries (branches of the pulmonary trunk) that carry venous blood from the heart to the lungs
    Cytoskeleton

    Main article: Cytoskeleton

    Bovine
    Pulmonary Artery Endothelial cell: nuclei stained blue, mitochondria stained red, and F-actin, an important component in microfilaments, stained green.

  160. component

    one of the individual parts making up a larger entity
    Eukaryotic cells

    Main article: Eukaryote

    Diagram of a typical animal (eukaryotic) cell, showing subcellular
    components.

  161. citric

    of or related to citric acid
    The second pathway, called the Krebs cycle, or
    citric acid cycle, occurs inside the mitochondria and can generate enough ATP to run all the cell functions.
  162. white blood cell

    blood cells that engulf and digest bacteria and fungi
    For wound healing to occur,
    white blood cells and cells that ingest bacteria move to the wound site to kill the microorganisms that cause infection.
  163. filament

    a thin wire heated by the passage of an electric current
    The eukaryotic cytoskeleton is composed of microfilaments, intermediate
    filaments and microtubules.
  164. acid

    a sour water-soluble compound with a pH of less than 7
    Genetic material

    Two different kinds of genetic material exist: deoxyribonucleic
    acid (DNA) and ribonucleic acid (RNA).
  165. functional

    designed for or capable of a particular use
    Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word "cell" being used to describe the smallest unit of a living organism

    Cells in culture, stained for keratin (red) and DNA (green)The cell is the
    functional basic unit of life.
  166. streptococcus

    spherical Gram-positive bacteria occurring in pairs or chains; cause e.g. scarlet fever and tonsillitis
    The capsule may be polysaccharide as in pneumococci, meningococci or polypeptide as Bacillus anthracis or hyaluronic acid as in
    streptococci.[citation needed] Capsules are not marked by ordinary stain and can be detected by special stain.
  167. microscope

    magnifier of the image of small objects
    Drawing of the structure of cork as it appeared under the
    microscope to Robert Hooke from Micrographia which is the origin of the word "cell" being used to describe the smallest unit of a living organism

    Cells in culture, stained for keratin (red) and DNA (green)The cell is the functional basic unit of life.
  168. nuclear

    constituting the core or central part
    Nuclear material of prokaryotic cell consist of a single chromosome which is in direct contact with cytoplasm.
  169. fungus

    a spore-producing organism that lacks chlorophyll
    Some eukaryote cells (plant cells and
    fungi cells) also have a cell wall;

    Inside the cell is the cytoplasmic region that contains the cell genome (DNA) and ribosomes and various sorts of inclusions.
  170. transcribe

    write out, as from speech or notes
    During processing, DNA is
    transcribed, or copied into a special RNA, called messenger RNA (mRNA).
  171. solar energy

    energy from the sun that is converted into thermal or electrical energy
    Organelles that are modified chloroplasts are broadly called plastids, and are involved in energy storage through photosynthesis, which uses
    solar energy to generate carbohydrates and oxygen from carbon dioxide and water.[citation needed]

    Mitochondria and chloroplasts each contain their own genome, which is separate and distinct from the nuclear genome of a cell.
  172. ingest

    take food, drink, or some other substance into the body
    For wound healing to occur, white blood cells and cells that
    ingest bacteria move to the wound site to kill the microorganisms that cause infection.
  173. nutrient

    any substance that can be metabolized to give energy
    Mitochondria generate the cell's energy by oxidative phosphorylation, using oxygen to release energy stored in cellular
    nutrients (typically pertaining to glucose) to generate ATP. Mitochondria multiply by splitting in two.
  174. chemical reaction

    a process in which substances are changed into others
    RNA is generally assumed to be the earliest self-replicating molecule, as it is capable of both storing genetic information and catalyzing
    chemical reactions (see RNA world hypothesis).
  175. cerebellum

    a major division of the vertebrate brain
    The largest cells are about 135 µm in the anterior horn in the spinal cord while granule cells in the
    cerebellum, the smallest, can be some 4 µm and the longest cell can reach from the toe to the lower brain stem (Pseudounipolar cells).[2]
  176. metabolic

    of or relating to metabolism
    The major difference between prokaryotes and eukaryotes is that eukaryotic cells contain membrane-bound compartments in which specific
    metabolic activities take place.
  177. sequestration

    the act of segregating or sequestering
    Smooth ER plays a role in calcium
    sequestration and release.
  178. bacterium

    single-celled or noncellular organisms lacking chlorophyll
    A prokaryotic chromosome is usually a circular molecule (an exception is that of the
    bacterium Borrelia burgdorferi, which causes Lyme disease).
  179. evolutionary

    relating to the development of a species
    Both organelles contain this DNA in circular plasmids, much like prokaryotic cells, strongly supporting the
    evolutionary theory of endosymbiosis; since these organelles contain their own genomes and have other similarities to prokaryotes, they are thought to have developed through a symbiotic relationship after being engulfed by a primitive cell.[citation needed]

    Endoplasmic reticulum – eukaryotes only

    The endoplasmic reticulum (ER) is the transport network for molecules targeted ...
  180. amoeba

    a single-celled organism that lives in water or soil
    Some cells, most notably
    Amoeba, have contractile vacuoles, which can pump water out of the cell if there is too much water.
  181. fatty acid

    any of a class of aliphatic monocarboxylic acids that form part of a lipid molecule and can be derived from fat by hydrolysis; fatty acids are simple molecules built around a series of carbon atoms linked together in a chain of 12 to 22 carbon atoms
    The early cell membranes were probably more simple and permeable than modern ones, with only a single
    fatty acid chain per lipid.
  182. polarity

    a relation between two opposite attributes or tendencies
    The prokaryotic cytoskeleton is less well-studied but is involved in the maintenance of cell shape,
    polarity and cytokinesis.[8]
  183. fluorescent

    emitting light during exposure to external radiant energy
    Cell imaged on a
    fluorescent microscope.The cytoskeleton acts to organize and maintain the cell's shape; anchors organelles in place; helps during endocytosis, the uptake of external materials by a cell, and cytokinesis, the separation of daughter cells after cell division; and moves parts of the cell in processes of growth and mobility.
  184. biological

    pertaining to life and living things
    The descriptive term for the smallest living
    biological structure was coined by Robert Hooke in a book he published in 1665 when he compared the cork cells he saw through his microscope to the small rooms monks lived in.[6
  185. connective tissue

    tissue of mesodermal origin consisting of e.g. collagen fibroblasts and fatty cells; supports organs and fills spaces between them and forms tendons and ligaments
    At the same time fibroblasts (
    connective tissue cells) move there to remodel damaged structures.
  186. humans

    all of the living human inhabitants of the earth
    Other organisms, such as
    humans, are multicellular.
  187. ion

    a particle that is electrically charged positive or negative
    The membrane is said to be 'semi-permeable', in that it can either let a substance (molecule or
    ion) pass through freely, pass through to a limited extent or not pass through at all.
  188. peroxide

    a viscous liquid with strong oxidizing properties
    Peroxisomes have enzymes that rid the cell of toxic
    peroxides.
  189. evolve

    undergo development
    Origin of eukaryotic cells

    The eukaryotic cell seems to have
    evolved from a symbiotic community of prokaryotic cells.
  190. oxygen

    a colorless, odorless gas that is essential for respiration
    Mitochondria generate the cell's energy by oxidative phosphorylation, using
    oxygen to release energy stored in cellular nutrients (typically pertaining to glucose) to generate ATP. Mitochondria multiply by splitting in two.
  191. blood cell

    either of two types of cells (erythrocytes and leukocytes) and sometimes including platelets
    For wound healing to occur, white
    blood cells and cells that ingest bacteria move to the wound site to kill the microorganisms that cause infection.
  192. vegetative

    of or relating to an activity that is passive and monotonous
    This leads to growth in multicellular organisms (the growth of tissue) and to procreation (
    vegetative reproduction) in unicellular organisms.
  193. bovine

    any of various wild or domestic cattle
    Cytoskeleton

    Main article: Cytoskeleton

    Bovine Pulmonary Artery Endothelial cell: nuclei stained blue, mitochondria stained red, and F-actin, an important component in microfilaments, stained green.

  194. bacterial

    relating to single-celled microorganisms
    Prokaryotic genetic material is organized in a simple circular DNA molecule (the
    bacterial chromosome) in the nucleoid region of the cytoplasm.
  195. virus

    infectious agent that replicates itself within living hosts
    Most organisms use DNA for their long-term information storage, but some
    viruses (e.g., retroviruses) have RNA as their genetic material.
  196. connective

    connecting or tending to connect
    At the same time fibroblasts (
    connective tissue cells) move there to remodel damaged structures.
  197. tumor

    an abnormal new mass of tissue that serves no purpose
    In the case of
    tumor development, cells from a primary tumor move away and spread to other parts of the body.
  198. complementary

    serving to fill out, enhance, or supply what is lacking
    Transcription is the process where genetic information in DNA is used to produce a
    complementary RNA strand.
  199. condense

    cause a gas or vapor to change into a liquid
    Though not forming a nucleus, the DNA is
    condensed in a nucleoid.
  200. gene

    part of DNA controlling physical characteristics and growth
    All cells possess DNA, the hereditary material of
    genes, and RNA, containing the information necessary to build various proteins such as enzymes, the cell's primary machinery.
  201. coupling

    the act of pairing a male and female for reproductive purposes
    Cilia may thus be "viewed as sensory cellular antennae that coordinate a large number of cellular signaling pathways, sometimes
    coupling the signaling to ciliary motility or alternatively to cell division and differentiation."[7]
  202. carbohydrate

    an essential component of living cells and source of energy
    Organelles that are modified chloroplasts are broadly called plastids, and are involved in energy storage through photosynthesis, which uses solar energy to generate
    carbohydrates and oxygen from carbon dioxide and water.[citation needed]

    Mitochondria and chloroplasts each contain their own genome, which is separate and distinct from the nuclear genome of a cell.
  203. chemically

    with respect to chemistry
    Complex sugars consumed by the organism can be broken down into a less
    chemically complex sugar molecule called glucose.
  204. mucous membrane

    mucus-secreting membrane lining all body cavities or passages that communicate with the exterior
    It also plays a role in attachment of the organism to
    mucous membranes.[citation needed]

    Flagella

    Flagella are the organelles of cellular mobility.

  205. theory

    a belief that can guide behavior
    In 1835, before the final cell
    theory was developed, Jan Evangelista Purkyně observed small "granules" while looking at the plant tissue through a microscope.
  206. migrate

    move from one country or region to another and settle there
    This RNA strand is then processed to give messenger RNA (mRNA), which is free to
    migrate through the cell. mRNA molecules bind to protein-RNA complexes called ribosomes located in the cytosol, where they are translated into polypeptide sequences.
  207. environment

    the totality of surrounding conditions
    The envelope gives rigidity to the cell and separates the interior of the cell from its
    environment, serving as a protective filter.
  208. pulmonary

    relating to or affecting the lungs
    Cytoskeleton

    Main article: Cytoskeleton

    Bovine
    Pulmonary Artery Endothelial cell: nuclei stained blue, mitochondria stained red, and F-actin, an important component in microfilaments, stained green.

  209. secrete

    generate and separate from cells or bodily fluids
    The ER has two forms: the rough ER, which has ribosomes on its surface and
    secretes proteins into the cytoplasm, and the smooth ER, which lacks them.
  210. mediate

    act between parties with a view to reconciling differences
    The ribosome
    mediates the formation of a polypeptide sequence based on the mRNA sequence.
  211. spinal cord

    a major part of the central nervous system which conducts sensory and motor nerve impulses to and from the brain; a long tubelike structure extending from the base of the brain through the vertebral canal to the upper lumbar region
    The largest cells are about 135 µm in the anterior horn in the
    spinal cord while granule cells in the cerebellum, the smallest, can be some 4 µm and the longest cell can reach from the toe to the lower brain stem (Pseudounipolar cells).[2]
  212. phosphorus

    a multivalent nonmetallic element of the nitrogen family that occurs commonly in inorganic phosphate rocks and as organic phosphates in all living cells; is highly reactive and occurs in several allotropic forms
    This membrane serves to separate and protect a cell from its surrounding environment and is made mostly from a double layer of lipids (hydrophobic fat-like molecules) and hydrophilic
    phosphorus molecules.
  213. differentiation

    a discrimination between things as distinct
    Cilia may thus be "viewed as sensory cellular antennae that coordinate a large number of cellular signaling pathways, sometimes coupling the signaling to ciliary motility or alternatively to cell division and
    differentiation."[7]
  214. bacillus

    aerobic rod-shaped spore-producing bacterium
    The capsule may be polysaccharide as in pneumococci, meningococci or polypeptide as
    Bacillus anthracis or hyaluronic acid as in streptococci.[citation needed] Capsules are not marked by ordinary stain and can be detected by special stain.
  215. vaccination

    taking a substance, usually by injection, against a disease
    An 'origin of sex as
    vaccination' theory suggests that the eukaryote genome accreted from prokaryan parasite genomes in numerous rounds of lateral gene transfer.
  216. inclusion

    the act of making a part of something
    Some eukaryote cells (plant cells and fungi cells) also have a cell wall;

    Inside the cell is the cytoplasmic region that contains the cell genome (DNA) and ribosomes and various sorts of
    inclusions.
  217. antibiotic

    a substance used to kill microorganisms and cure infections
    Plasmids enable additional functions, such as
    antibiotic resistance.
  218. hydrogen

    a nonmetallic univalent element that is normally a colorless and odorless highly flammable diatomic gas; the simplest and lightest and most abundant element in the universe
    Each reaction is designed to produce some
    hydrogen ions that can then be used to make energy packets (ATP).
  219. mucous

    of or secreting or covered with or resembling mucus
    It also plays a role in attachment of the organism to
    mucous membranes.[citation needed]

    Flagella

    Flagella are the organelles of cellular mobility.

  220. carbon dioxide

    a heavy odorless colorless gas formed during respiration and by the decomposition of organic substances; absorbed from the air by plants in photosynthesis
    Organelles that are modified chloroplasts are broadly called plastids, and are involved in energy storage through photosynthesis, which uses solar energy to generate carbohydrates and oxygen from
    carbon dioxide and water.[citation needed]

    Mitochondria and chloroplasts each contain their own genome, which is separate and distinct from the nuclear genome of a cell.
  221. isolate

    place or set apart
    The nuclear envelope
    isolates and protects a cell's DNA from various molecules that could accidentally damage its structure or interfere with its processing.
  222. sperm

    the male reproductive cell; the male gamete
    Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes

    Typical organisms bacteria, archaea protists, fungi, plants, animals

    Typical size ~ 1–10 µm ~ 10–100 µm (
    sperm cells, apart from the tail, are smaller)

    Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane

    DNA circular (usually) linear molecules (chromosomes) with histone proteins

    RNA-/protein-synthesis coupled in cytoplasm RNA-synthesis inside the nucleu...
  223. calcium

    a white metallic element that burns with a brilliant light
    Smooth ER plays a role in
    calcium sequestration and release.
  224. virulent

    extremely poisonous or injurious; producing venom
    Sex-as-syngamy (fusion sex) arose when infected hosts began swapping nuclearized genomes containing co-evolved, vertically transmitted symbionts that conveyed protection against horizontal infection by more
    virulent symbionts
  225. derivative

    a compound obtained from another compound
    Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes

    Typical organisms bacteria, archaea protists, fungi, plants, animals

    Typical size ~ 1–10 µm ~ 10–100 µm (sperm cells, apart from the tail, are smaller)

    Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane

    DNA circular (usually) linear molecules (chromosomes) with histone proteins

    RNA-/protein-synthesis coupled in cytoplasm RNA-synthesis inside the nucleus

    prot...
  226. fatty

    containing or composed of fat
    The early cell membranes were probably more simple and permeable than modern ones, with only a single
    fatty acid chain per lipid.
  227. dioxide

    an oxide containing two atoms of oxygen in the molecule
    Organelles that are modified chloroplasts are broadly called plastids, and are involved in energy storage through photosynthesis, which uses solar energy to generate carbohydrates and oxygen from carbon
    dioxide and water.[citation needed]

    Mitochondria and chloroplasts each contain their own genome, which is separate and distinct from the nuclear genome of a cell.
  228. spindle

    a stick or pin used to twist the yarn when making thread
    Centrosomes are composed of two centrioles, which separate during cell division and help in the formation of the mitotic
    spindle.
  229. toxic

    of or relating to or caused by a poison
    Peroxisomes have enzymes that rid the cell of
    toxic peroxides.
  230. digestive

    a substance that aids the process of breaking down food
    Lysosomes and Peroxisomes – eukaryotes only

    Lysosomes contain
    digestive enzymes (acid hydrolases).
  231. appendage

    a part that is joined to something larger
    They are long and thick thread-like
    appendages, protein in nature.
  232. antenna

    one of a pair of mobile appendages on the head of insects
    Cilia may thus be "viewed as sensory cellular
    antennae that coordinate a large number of cellular signaling pathways, sometimes coupling the signaling to ciliary motility or alternatively to cell division and differentiation."[7]
  233. embed

    fix or set securely or deeply
    Embedded within this membrane is a variety of protein molecules that act as channels and pumps that move different molecules into and out of the cell.
  234. hereditary

    occurring among people descended from a common ancestor
    The cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that all cells come from preexisting cells, that vital functions of an organism occur within cells, and that all cells contain the
    hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.[5]
  235. secretion

    the organic process of releasing some substance
    It is particularly important in the processing of proteins for
    secretion.
  236. anterior

    of or near the head end or toward the front plane of a body
    The largest cells are about 135 µm in the
    anterior horn in the spinal cord while granule cells in the cerebellum, the smallest, can be some 4 µm and the longest cell can reach from the toe to the lower brain stem (Pseudounipolar cells).[2]
  237. generator

    someone who originates, causes, or initiates something
    Diagram of a cell nucleus

    Mitochondria and Chloroplasts – eukaryotes only - the power
    generators

    Mitochondria are self-replicating organelles that occur in various numbers, shapes, and sizes in the cytoplasm of all eukaryotic cells.
  238. respiration

    a single complete act of breathing in and out
    Respiration occurs in the cell mitochondria.
  239. fluid

    continuous amorphous matter that tends to flow
    It may also be called a
    fluid mosaic membrane.
  240. hormone

    the secretion of an endocrine gland transmitted by the blood
    Cell surface membranes also contain receptor proteins that allow cells to detect external signaling molecules such as
    hormones.
  241. lateral

    situated at or extending to the side
    An 'origin of sex as vaccination' theory suggests that the eukaryote genome accreted from prokaryan parasite genomes in numerous rounds of
    lateral gene transfer.
  242. ostrich

    fast-running African flightless bird with two-toed feet
    The largest known cells are unfertilised
    ostrich egg cells which weigh 3.3 pounds.[3][4]
  243. fusion

    the act of melding or melting together
    Sex-as-syngamy (
    fusion sex) arose when infected hosts began swapping nuclearized genomes containing co-evolved, vertically transmitted symbionts that conveyed protection against horizontal infection by more virulent symbionts
  244. parasite

    an animal or plant that lives in or on a host
    An 'origin of sex as vaccination' theory suggests that the eukaryote genome accreted from prokaryan
    parasite genomes in numerous rounds of lateral gene transfer.
  245. immune

    of the condition in which an organism can resist disease
    Movement or motility

    Cells can move during many processes: such as wound healing, the
    immune response and cancer metastasis.
  246. spinal

    of or relating to the spine or spinal cord
    The largest cells are about 135 µm in the anterior horn in the
    spinal cord while granule cells in the cerebellum, the smallest, can be some 4 µm and the longest cell can reach from the toe to the lower brain stem (Pseudounipolar cells).[2]
  247. human body

    alternative names for the body of a human being
    Organelles

    Main article: Organelle

    The
    human body contains many different organs, such as the heart, lung, and kidney, with each organ performing a different function.
  248. mosaic

    design made of small pieces of colored stone or glass
    It may also be called a fluid
    mosaic membrane.
  249. anatomy

    the study of the structure of animals
    Anatomy

    There are two types of cells: eukaryotic and prokaryotic.
  250. reaction

    an idea evoked by some experience
    Each
    reaction is designed to produce some hydrogen ions that can then be used to make energy packets (ATP).
  251. reproduction

    the act of making copies
    This leads to growth in multicellular organisms (the growth of tissue) and to procreation (vegetative
    reproduction) in unicellular organisms.
  252. human

    a person; a hominid with a large brain and articulate speech
    Other organisms, such as
    humans, are multicellular.
  253. infected

    containing or resulting from disease-causing organisms
    Sex-as-syngamy (fusion sex) arose when
    infected hosts began swapping nuclearized genomes containing co-evolved, vertically transmitted symbionts that conveyed protection against horizontal infection by more virulent symbionts
  254. experimental

    of the nature of or undergoing a trial
    There are essentially no
    experimental data defining what the first self-replicating forms were.
  255. infect

    contaminate with a disease
    Sex-as-syngamy (fusion sex) arose when
    infected hosts began swapping nuclearized genomes containing co-evolved, vertically transmitted symbionts that conveyed protection against horizontal infection by more virulent symbionts
  256. carbon

    an abundant nonmetallic element in all organic compounds
    Organelles that are modified chloroplasts are broadly called plastids, and are involved in energy storage through photosynthesis, which uses solar energy to generate carbohydrates and oxygen from
    carbon dioxide and water.[citation needed]

    Mitochondria and chloroplasts each contain their own genome, which is separate and distinct from the nuclear genome of a cell.
  257. solar

    relating to the sun or utilizing the energies of the sun
    Organelles that are modified chloroplasts are broadly called plastids, and are involved in energy storage through photosynthesis, which uses
    solar energy to generate carbohydrates and oxygen from carbon dioxide and water.[citation needed]

    Mitochondria and chloroplasts each contain their own genome, which is separate and distinct from the nuclear genome of a cell.
  258. atmosphere

    the envelope of gases surrounding any celestial body
    A third is that they were synthesized by lightning in a reducing
    atmosphere (see Miller–Urey experiment); although it is not clear if Earth had such an atmosphere.
  259. particle

    (nontechnical usage) a tiny piece of anything
    They digest excess or worn-out organelles, food
    particles, and engulfed viruses or bacteria.
  260. data

    a collection of facts from which conclusions may be drawn
    There are essentially no experimental
    data defining what the first self-replicating forms were.
  261. liquid

    fluid matter having no fixed shape but a fixed volume
    They are often described as
    liquid filled space and are surrounded by a membrane.
  262. lung

    either of two saclike respiratory organs in the chest of vertebrates; serves to remove carbon dioxide and provide oxygen to the blood
    Organelles

    Main article: Organelle

    The human body contains many different organs, such as the heart,
    lung, and kidney, with each organ performing a different function.
  263. evolution

    sequence of events involved in the development of a species
    Evolution

    Main article: Evolutionary history of life

    The origin of cells has to do with the origin of life, which began the history of life on Earth.
  264. cancer

    a malignant growth caused by uncontrolled cell division
    Movement or motility

    Cells can move during many processes: such as wound healing, the immune response and
    cancer metastasis.
  265. chemical

    produced by reactions involving atomic or molecular changes
    RNA is generally assumed to be the earliest self-replicating molecule, as it is capable of both storing genetic information and catalyzing
    chemical reactions (see RNA world hypothesis).
Created on October 5, 2010

Leave a Comment

Pin It on Pinterest

Share This
Open chat