unit 3 cell division lesson 1, 2,3,4, 5, 6 Flashcards

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1
Q

the cell cycle is made up of two main stages, what are they?

A

growth stage, and a division stage

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2
Q

what is the growth stage for somatic cells?

A

interphase is where the cell spends most of its time growing

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3
Q

what are the stages of interphase?

A

G1, synthesis and G2

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4
Q

what is G1 explain what happens during this process.

A
  • metabolic processes prepare the cell for division
  • at a certain point, the cell is committed to cell division and moves into the S phase of interphase
  • here rapid growth takes place
    -cells accomplish most of their growth. They get bigger in size and make proteins and organelles needed for normal functions of DNA synthesis. Here, proteins and RNAs are synthesized, and, more especially the centromere and the other components of the centrosomes are made.
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5
Q

what is Synthesis and what happens during this?

A

DNA synthesis replicates the genetic material
- each chromosome now consists of 2 sister chromatids
- about midway through interphase, the cell’s DNA is copied exactly. That is, the DNA in the chromatin replicates to create a second identical set of DNA. These two identical chromosomes are called sister chromatids, are joined at the centromere because new genetic material is synthesized

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6
Q

what is G2 in interphase and what happens during this?

A

metabolic changes assemble the cytoplasmic materials necessary for mitosis and cytokinesis

-the shortest phase (organelles and molecules required for cell division are produced)

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6
Q

what is G2 in interphase and what happens during this?

A

metabolic changes assemble the cytoplasmic materials necessary for mitosis and cytokinesis

-the shortest phase (organelles and molecules required for cell division are produced)

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7
Q

what are the two main processes in cell division?

A
  • mitosis
  • cytokinesis
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8
Q

what is mitosis?

A

the division of the genetic material and the contents of the nucleus into two complete and separate sets
- a division of the nucleus

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9
Q

what is cytokinesis?

A

the division of the cytoplasm and the organelles into two separate cells
- a division of cytoplasm

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10
Q

What is P.MAT

A
  1. prophase
  2. metaphase
  3. anaphase
  4. telophase
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11
Q

what is prophase?

A
  • nuclear membrane disappears
  • nucleolus disappears
  • spindle fibers appear from centrioles
  • chromatin condenses into distinct chromosomes
  • replicated chromosomes
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12
Q

what is metaphase?

A
  • chromosomes line up along the equator of the cell
  • spindle fibres attach to each chromatid
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12
Q

what is metaphase?

A
  • chromosomes line up along the equator of the cell
  • spindle fibers attach to each chromasome
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13
Q

what is anaphase?

A
  • spindle fibres contract pulling one chromatid from each pair to opposite ends of the cell
  • centromeres split and the sister chromatids are pulled apart to opposite poles of the cell
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14
Q

what is telophase ?

A
  • nucleolus reappears
  • nuclear membrane reappears
  • chromosomes uncondense into chromatin
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15
Q

what is cytokinesis?

A
  • this is the division of the cytoplasm
  • once the nucleus has divided the cell membrane punches inward separating the cytoplasm in half.
  • the result is that there are two cells with the exact same genetic information
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16
Q

what is cytokinesis called in animals?

A

cleavage furrowing
-cleavage furrow constricts like a drawstring to separate the cells

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17
Q

what is cytokinesis in plants?

A

cell plate forms a cell wall between the two daughter cells

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18
Q

what is a chromatin ?

A

granular material visible within the nucleus; consists of DNA tightly coiled around proteins
(uncondensed )

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19
Q

what are homologous chromosomes

A

chromosomes of similar lengths and bonding patterns

20
Q

haploid

A

n= 23

21
Q

diploid

A

2n=46

22
Q

purpose and significance of the evolution of meiosis ?

A
  • the sole purpose of meiosis is to make sex cells; sperm and egg collectively known as gametes
  • gametes have half the normal number of chromosomes as a diploid cell; hence gametes are haploid cells
  • by making gametes, the opportunity for recombination exists for the first time, creating zygotes that are variable from the parent
23
Q

what is Meiosis I and what does it accomplish?

A
  • separates the matching or “homologous” pairs of chromosomes; (in this division, variation can occur in prophase I (due to crossovers) or metaphase I (due to independent assortment)
24
Q

what is meiosis II?

A

separates the sister chromatids into individual chromosomes (this is much like mitosis)

25
Q

what prophase I?

A
  • chromatin condenses into chromosomes
  • Nuclear membrane and nucleolus disappear
  • spindle fibers appear
  • homologous chromosomes pair together and chromosomes can cross over which creates variation
    -homologous chromosomes pair up and form tetrads, crossing over occurs
26
Q

what is metaphase I ?

A
  • tetrads line up along the equator
  • spindle fibres attach
27
Q

what is Anaphase I?

A
  • replicated homologous chromosomes (pairs) get pulled apart.
28
Q

Telophase 1?

A
  • two cells form chromosomes are still replicated
    -nucleolus reappears
  • replicated chromosomes uncondensed
  • nuclear membrane reforms and nucleolus reforms
29
Q

cytokinesis I?

A
  • seperate
30
Q

prophase II?

A
  • condensing of chromatin
  • NM and nucleolus disappear
  • spindle fibres
    appear
31
Q

metaphase II?

A
  • replicated chromosomes line up at the top of each other
  • spindles attach
  • now there are two cells
32
Q

Anaphase II?

A
  • sister chromatids separate by contraction of spindle fibres
    chromatids pulled apart into single chromosomes
33
Q

telophase II?

A
  • opposite of prophase II
  • the chromosomes gather into nuclei and the cells divide
  • chromosomes uncoil into chromatin
34
Q

cytokinesis II?

A
  • haploid cells forming
  • cell membranes pinch in to separate the cells into four haploid cells
35
Q

what is nondisjunction?

A

failure of homologous chromosomes or sister chromatids to separate normally during meiosis

36
Q

what is monosomy

A

when one chromosome is lost due to conjunction

37
Q

what is trisomy ?

A

the gain of an extra chromosome

38
Q

what is spermatogonium?

A

the process of spermatogenesis starts with a diploid germ cell, beginning at puberty spermatogonia are stimulated to divide by mitosis to form two daughter cells
- diploid germ cell

39
Q

what is primary spermatocyte ?

A

undergoes meiosis I
- one of two daughter cells formed by division of the spermatogonia, the other daughter cell replenishes the spermatogonia population

40
Q

secondary spermatocyte?

A

each of two cells produces as a result of a primary spermatocyte undergoing meiosis I

41
Q

spermatid?

A

each of four haploid cells that result when a secondary spermatocyte undergoes meiosis II, each spermatid differentiates into the sperm cell

42
Q

what is oogonium?

A

diploid germ cell for oogenesis

43
Q

what is a primary oocyte?

A

undergoes meiosis I and secondary goes through Meiosis II

43
Q

what is a primary oocyte?

A

undergoes meiosis I and secondary goes through Meiosis II

44
Q

what is alternation of generations?

A

the life cycle of plants consists of two generations: a haploid generation and a diploid generation that alternate.
- this is called the alternation of generations
- only in plants

45
Q

typical animal life cycle?

A

the human life cycle is based on a regular pattern of meiosis, mitosis and fertilization

46
Q

what is the diploid generation of plants called?

A

sporophyte, through this process of meiosis, the sporophyte produces one or more haploid spores. These spores develop without fertilization.

47
Q

what does haploid spores grow into?

A

gametophyte (gamete-making body)
- gametophytes produce male and female gametes, which fuse at fertilization and develop into another sporophyte. The cycle repeats.