Chapter 12 Cell cycle Flashcards

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1
Q

Cell cycle

A

Life cycle of a cell

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2
Q

What are the stages of the cell cycle in eukaryotic cells (cells with a nucleus)

A

Interphase and mitotic phase

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3
Q

What happens in interphase

A

The cell grows and makes a copy of its DNA

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4
Q

What happens in G1 phase

A

The cell grows physically larger,
Copies organelles

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5
Q

What happens in S phase

A

The cell synthesizes a complete copy of the DNA in its nucleus

Duplicates a microtubule-organizing structure called the centrosome which helps division during mitosis

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6
Q

What happens during G2 phase

A

The cell grows more,
Makes proteins and organelles

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7
Q

What are the 3 stages of interphase

A

G1, S, and G2 phase

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8
Q

What happens in the M phase and what are its processes

A

Cell divides its copied DNA and cytoplasm to make two new cells

Two parts processes are mitosis and cytokinesis

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9
Q

What happens in Cytokinesis and where does it take place

A

The cytoplasm of the cell is split in two making two new cells. w

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10
Q

Cytokinesis in animal cells

A

Contractile cytokinesis pinches the cell in two making the cleavage furrow

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11
Q

Cytokinesis in plant cells

A

Plant cells divide in two by the cell plate that forms in the middle

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12
Q

What is the G0 phase

A

Its where cells that do not divide that exit the G1 phase, enters a resting phase called G0 phase.

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13
Q

What is mitosis

A

Process where one mother cell produces 2 daughter cells that are identical to itself that each have a full pair of chromosomes

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14
Q

What is the process of cytokinesis and in what stage of mitosis does it start

A

process of dividing the cell contents to make two new cells

Starts in anaphase or telophase

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15
Q

Sister chromatids

A

two identical chromatids that are formed by replication of a chromosome during the S phase of the cell cycle, are joined by a centromere, and segregate into separate daughter cells during anaphase

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16
Q

What happens in early prophase

A
  1. Chromosomes start to condense
  2. Mitotic spindles form
  3. Centrosomes move towards opposite sides of the cell
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17
Q

What happens in prometaphase

A
  1. Nuclear envelope disappears
  2. Mitotic spindle grows more
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17
Q

Centromeres

A

Regions of DNA where the sister chromatids are most tightly connected

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17
Q

Kinetochore

A

Patch of protein found on the centromere of each sister chromatin that microtubules bind to at chromosomes

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18
Q

Aster

A

Cellular structure is shaped like a star, formed around each centrosome during mitosis in an animal cell

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19
Q

Kinetomicrotubules

A

A part of the mitotic spindle that is able to bind to the kinetochores

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20
Q

Metaphase

A

At this stage the spindle captured all the chromosomes and lined them up at the middle of the cell

  1. All chromosomes align at the metaphase plate
  2. The kinetochores are attached to the microtubules
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21
Q

Spinal checkpoint

A

Cell checks to make sure the chromosomes are at the metaphase plate with their kinetochores correctly attached to microtubules

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22
Q

Telophase

A

Chromosome decondense and return to stringy form
Mitotic spindle breaks down
Nuclear envelope redevelops

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23
Q

What happens in anaphase

A

Chromatids are split apart and pulled to the opposite ends of the cell by the kinetochore microtubules
Each chromatid is now their own molecule

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24
Q

What do motor proteins do in mitosis

A

Drives all the processes of mitosis
.

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25
Q

Cleavage furrow

A

Divides the cytoplasm to create split a cell into two new ones using a pinch

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26
Q

Cell plate

A

Structure that forms down middle of the cell and splits it into two daughter cells separated by a new wall

27
Q

DNA

A

genetic material of all organisms and found in cells

Every cell that divides passes a copy of its DNA to each of its daughter cells

28
Q

Genes

A

Units in which DNA is organized and genes give instructions for making proteins

29
Q

Nucleoid

A

Central region of the cell which has the most DNA. Functions like the nucleus but without a membrane

30
Q

Genome

A

cell’s set of DNA

31
Q

Histones

A

Specialized proteins that organize DNA and give it structure in eukaryotic cells.
Determines which genes are active

32
Q

Chromatin

A

the combination of DNA and proteins that make up the genetic material of chromosomes.

33
Q

Chromosomes

A

Threadlike structures made of protein and single molecule of DNA

34
Q

Diploid (2n)

A

Has 46 chromosomes, has paired sets of chromosomes called homologous chromosomes

35
Q

Haploid (1n)

A

Contains one homologous chromosome from each pair.

Has 23 chromosomes

Examples are sperm and eggs

36
Q

Cohesins

A

Proteins that attach sister chromatids to each other

37
Q

gametes

A

sex cells, sperm and eggs

38
Q

Meiosis

A

Process where a single cell divides twice to produce four cells containing half the original amount of genetic information

39
Q

sister chromatids

A

One-half of the duplicated chromosome that’s formed by DNA replication of a chromosome.

39
Q

Homologous chromosomes

A

Similar but nonidentical chromosome pairs an organism receives from its two parents

Essentially same gene, loci (genetic position, centromere location and chromosomal length. They only differ in alleles.

40
Q

Meiosis I

A

Homologoue pairs seperate during a first round of cell division

40
Q

Meiosis II

A

Sister chromatids separate during a second round.

41
Q

Prophase I

A

The chromosomes condense but each chromosomes also pairs up with its homologous partner

Crossing over occurs: Homologous chromosomes trade parts

42
Q

Synaptonemal complex

A

Holds homologues together.

42
Q

Metaphase I

A

Spindle captures chromosomes
homologue pairs line up at the metaphase plate for separation
Each chromosome attaches to the microtubules from just one pole of the spindle

43
Q

Anaphase I

A

The spindle fibers shorten and pull each homologous chromosome to one side
Homologous are pulled apart and move to opposite ends of the cell

44
Q

Telophase I

A

Chromosomes arrive at opposite poles of the cell.
The nuclear envelope develops again
Chromosomes decondense

45
Q

Meiosis II

A

“Mitosis for haploid cells”

46
Q

prophase II

A

chromosomes condense and nucleur envelope breaks down

When the centresomes move apart, the spindle forms between them

47
Q

metaphase II

A

chromosomes line up individually along the metaphase plate

48
Q

Anaphase II

A

Sister chromatids separate and are pulled towards the opposite poles of the cell

49
Q

Telophase II

A

Nuclear membranes form around each set of chromosomes and the chromosomes decondense

50
Q

Cytokinesis in meiosis 2

A

Splits the chromosome sets into new cells, forming the final products of meiosis which are four haploid cells in which each chromosome has just one chromatid. Also each cell has half the chromosomes and a fourth of DNA of the parent cell

51
Q

Where does mitosis occur

A

Somatic cells

52
Q

Where does meiosis occur

A

Germ cells

52
Q

Difference between meiosis I and meiosis II

A

Pairs of homologous chromosomes are separated during meiosis I while sister chromatids are separated during meiosis II

53
Q

How are mitosis and meiosis similar

A

Sister chromatids segregate during both mitosis and meiosis. This occurs in anaphase of mitosis and anaphase II of meiosis

54
Q

Three importance checkpoints in the cell cycle

A

G1 checkpoint at G1/S transition

55
Q

G2 checkpoint at G2/M transition

A

The spindle checkpoint, at the transition from metaphase to anaphase

56
Q

G1 checkpoint

A

controls the commitment of eukaryotic cells to transition through the G1 phase to enter into the DNA synthesis S phase.

57
Q

G2 checkpoint

A

prevents cells from entering mitosis when DNA is damaged

58
Q

M checkpoint (spindle checkpoint)

A

Cell examines whether all sister chromatids are correctly attached to the spindle microtubules

59
Q

Cyclin

A

regulatory subunits of CDK complexes that control the progression through cell cycle checkpoints by phosphorylating and inactivating target substrates

60
Q

Cyclin-dependent kinases

A

Family of enzymes that can be activated if its binded with cyclin. After activation it modifies target proteins

61
Q

kinases

A

enzymes that phosphorylate (attach phosphate group to specific target proteins

62
Q

maturation-promoting factor (MPF)

A

G2 checkpoint regulates a cell from the G2 growth phase to the M phase

63
Q

How does cyclin levels change throughout the cell cycle

A

Stays at low levels for much of the cell cycle and builds up as the cell approaches G2 and M transition