cell growth and division Flashcards

1
Q

what cells in the body don’t undergo cell division

A
  • gametes
  • red blood cells
  • most neurons
  • some muscle cells
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2
Q

somatic cells

A

general term for a body cell and all human cells except for the cells that produce eggs and sperm (germ cells)
- contain 2 copies of each of their chromosomes (one copy received from each parent)

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3
Q

homologous

A
  • pair of chromosomes is the two copies of single chromosome found in each somatic cell
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4
Q

diploid organism

A
  • humans are!
  • have 23 homologous pairs of chromosomes in each of the somatic cells
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5
Q

diploidy

A

condition of having pairs of chromosomes

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6
Q

Interphase

A
  • period of cell cycle during which the cell is not dividing
  • majority of cells are in interphase
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7
Q

mitosis

A

division of genetic material during which cell nucleus breaks down and two new fully functional nuclei are formed

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8
Q

cytokinesis

A

divides the cytoplasm into two distinctive cells

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9
Q

what are the two general phases of the cell cycle

A
  • interphase
  • mitosis and cytokinesis
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10
Q

what are the phases in interphase?

A
  • g1 phase: growth phase (spend most of time here)
  • s phase: synthesis phase, cell replicates its dna, dna doubles
  • g2 phase: cell continues to grow and makes necessary preparations for mitosis
    g0 phase: resting phase of cell cycle, cells temporarily stop dividing and are resting, and those who have permenantly stopped dividing (nerve cells)
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11
Q

what are each copies of the chromosome called

A

sister chromatid

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12
Q

centromere

A

structure that attaches one sister chromatid to another
- 46 chromosomes (92 chromatids)

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13
Q

Mitotic Phase - what are the 2 parts?

A
  1. complete mitosis (contents of nucleus are equally pulled apart and distributed)
  2. cytokinesis (divides cytoplasm and cell body into 2 new cells)
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14
Q

what are the 4 major stages of mitosis?

A

prophase, metaphase, anaphase, and telophase

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15
Q

prophase

A
  • first phase of mitosis
    -loosely pascked chromatin coils and condenses into visible chromosomes
  • chromosomes become visible with identical partner attached
  • forms x shape of sister chromatids
  • nucleolus disappears early in this phase
  • nuclear envelope also disintegrates
  • centrosomes begin to move apart during prophase
  • centrosomes migrate to different sides of the cell
  • microtubules extend from each ends like fingers
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16
Q

centrosome

A
  • a pair of centrioles together
  • cell has 2 centrosomes side to side
17
Q

mitotic spindle

A

structure composed of centrosomes and their emerging microtubules

18
Q

mitotic phase

A
  • cell typically takes between 1-2 hrs
  • ## cell undergoes 2 major processes: mitosis and cytokinesis
19
Q

mitosis

A
  • the contents of the nucleus are equitably pulled apart and distributed between its two halves
  • four major stages after interphase: prophase, metaphase, anaphase, telophase
20
Q

cytokinesis

A

divides the cytoplasm and cell body into two new cells

21
Q

describe prophase

A
  1. prophase
    - chromosomes condense and become visible w a partner attached (forms x-shaped sister chromatids)
    - spindle fibers emerge from centrosomes
    - nuclear envelope breaks down
    - centrosomes move toward opposite poles
    - becomes an important structure that contains the site for microtubules growth.
22
Q
  1. prometaphse
A
  • chromosomes continue to condense
  • kinetochores appear at the centrosomes
    -mitotic spindle microtubules attach to kinetochores
23
Q
  1. metaphase
A
  • chromosomes are lined up at metaphase plate
  • each sister chromatid is attached to a spindle fiber originating from opposite poles
24
Q
  1. anaphase
A
  • centrosomes split in two and forms individual chromosomes
  • sister chromatids (now called chromosomes) are pulled towards opposite poles by kinetochores as microtubules shorten
  • certain spindle fibers begin to elongate the cell
  • each end of cell receivves one parter from each pair os sister chromatids
25
Q
  1. telophase
A
  • chromosomes arrive at oppostive poles and begin to decondense
  • nulear envelope material surrounds each set of chromosomes
  • new nucleoli from around nuclei
  • the mitotic spindle breaks down
  • spindle fibers continue to push poles apart
  • cell begins to split in half
26
Q
  1. cytokinesis
A
  • animal cells: a cleavage furrow separates the daughter cells
  • plant cells: a cell plate the precursor to a new cell wall, separates the daughter cells
27
Q

Centrosome

A
  • a pair of centrioles together
    -each cell contains 2 side-by-side
  • ## move apart during prophase
28
Q

centrioles

A
  • cellular structures that serve as origin points from which microtubules extend
29
Q

mitotic spindle

A
  • a structure composed of centrosomes and their emerging microtubules
30
Q

kinetochore

A

protein structure on the centromere that is the point of attachment between the mitotic spindle and sister chromatids

31
Q

metaphase plate

A

the name for the plane through the center of the spindle on which the sister chromatids are posisitoned

32
Q

cleavage furrow

A
  • contractile band made up of microfilaments that form around midline of cell during cytokinesis
  • microfilaments made up of actin
  • squeezes the two until they seperate
33
Q

Cyclin

A

one of primary classes of cell control molecules

34
Q

cyclin-dependent kinase (CDK)

A

one group of molecules that work together with cyclins to determine progression past cell checkpoints