Cell cycle, Mitosis, and Meiosis Flashcards

1
Q

What are the stages of the cell cycle?

A

Interphase- G1, S, G2
M phase
Cytokinesis

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2
Q

What happens in Interphase?

A

grows and makes a copy of its DNA- (90% of the cycle)

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3
Q

What occurs in G1?

A

cell grows larger, copies organelles and makes molecular building blocks

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4
Q

What occurs in S phase?

A

synthesizes a complete copy of the DNA( copies chromosomes) and duplicates the centrosomes

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5
Q

What occurs in G2?

A

grows more, makes proteins and organelles, and reorganizes for mitosis; ends when mitosis begins

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6
Q

What occurs in M phase?

A

formation of two new cells; divides DNA and cytoplasm

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7
Q

What occurs during cytokinesis?

A

cytoplasm of the cell split into two cells

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8
Q

G1 checkpoint description & what it checks for

A

whether the cell is prepared for division- most important

Checks for size, nutrients, and DNA damage; if not met it will not go into S phase

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9
Q

G2 checkpoint description and what it checks for

A

Mitotic phase

Checks for cell size, protein reserves, and all chromosomes have been replicated and DNA damage
- If problems exist→ cell either completes DNA replication or repairs DNA

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10
Q

M checkpoint description and what it checks for

A

near the end of metaphase of karyokinesis
- Checks if all the sister chromatids are correctly attached to the spindle microtubules

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11
Q

What is G0?

A

a resting state; not actively prepare dot divide
- Cells that do not receive go-ahead signal
- Can be a permanent state for some cells or temporary for some cells who can start division if they have the right signals

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12
Q

Describe CDKs?

A

enzymes that activate or inactivate other proteins by phosphorylating them; to be active they must bind to a cyclin

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13
Q

What is an MPF?

A

cyclin and CDK complex
Triggers cell passage past the G2 checkpoint and into M phase
Cyclins and CDKS bind in G2- phosphorylate proteins→ mitosis

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14
Q

What do peaks of MPF activity correspond with?

A

corresponds with cycling concentration; rise during S and G2 phases;falls during M phase

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15
Q

Why does MPF switches off?

A

destruction of its own cyclin

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16
Q

Difference between Somatic cells and Gametes?

A

Somatic Cells- 46 chromosomes- diploids cells
Gametes- 23 chromsomes- haploid cells

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17
Q

Difference between sister chromatids and chromosomes

A

Sister chromatids: are two indenticial strands of DNA that are attached by the centromere
Chromosomes: composed of chromatids

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18
Q

Stages of mitosis

A

prophase, metaphase, Anaphase, telophase

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19
Q

Describe what occurs in prohase?

A

-Nucleolus disappears
-chromatin condenses into chromosomes
-Separation of centrosomes
-Formation of mitotic spindle

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20
Q

Describe what occurs in prometaphase?

A

-Nuclear envelope disassembles
-Chromosomes form 2 kinetochores at the centromere
-Microtubules attach to the chromosomes

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21
Q

Describe what occurs at metaphase

A

Chromosomes align in the metaphase plate

22
Q

What occurs during anaphase?

A

Chromatids move apart to separate poles

23
Q

What occurs during telophase?

A

Nuclear envelope forms
Chromosomes unfold back into chromatin
Nucleoli reappear
Cell continues to elongate

24
Q

Cytokinesis in plants and animals

A

plants- cell plate
animals- cleavage furrow- cell pinches together

25
Q

Binary Fission

A

bacteria replicate circular chromosomes and then cytoplasm divides through cytokinesis.

26
Q

Chromosomes number in daughter cells vs. mother in binary fission

A

Daughter cells have the same chromosome number as the mother cell

27
Q

How is there more genetic vartiation in sexual reproduction compared to asexual?

A

Law of segregation
Law of Independent Assortment
Random Fertilization

28
Q

Define Law of Segregation

A

separation of alleles during gamete formation
Each gamete has 1 allele for each gene; varied combinations of alleles

29
Q

define Law of Independent Assortment

A

alleles of two (or more) different genes get sorted into gametes independently

30
Q

How is there genetic variation in random fertilization?

A

random unique egg gets fertilized by unique sperm

31
Q

Define karyotype

A

individual’s complete set of chromosomes

32
Q

Define autosomes

A

chromosomes other than sex chromosome

33
Q

Define sex chromosomes

A

XX and XY- determine the person’s gender
Exception to homologous chromosomes

34
Q

Define diploid cells

A

2 set of chromosomes

35
Q

Define haploid cell

A

1 set of chromosome

36
Q

Define homologous chromosomes

A

are a set of maternal and paternal chromosomes that pair up in a cell during fertilization

37
Q

Define tetrads

A

consists of two homologous chromosomes with a total of 4 sister chromatids

38
Q

what is the purpose of meiosis?

A

the creation of gamete cells

39
Q

Prophase 1

A
  • Synapsis occurs: maternal and paternal chromosomes(homologous chromosomes) wrap up tightly
    -Crossing Over: through synapsis, swap parts of chromsomes
40
Q

Describe metaphase 1

A

-Independent Orientation: ligning up at metaphase plate
-Spindals attaches to centromere of each homologous chromosome

41
Q

Describe Anaphase 1

A

Homologous chromosomes are pulled apart to opposite ends

42
Q

Describe telophase 1

A

Divide cell with cytokinesis

43
Q

Describe prophase 2

A

-No crossing over
-Chromosomes condense
-Nuclear envelope breaks down
-Spindle forms

44
Q

Describe metaphase 2

A

Chromosomes line up along the metaphase plate

45
Q

Describe Anaphase 2

A

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

46
Q

Describe telophase 2

A

-Nuclear membranes form around each set of chromosomes and chromosomes decondensed
-Cytokinesis continues

47
Q

Describe ploidy during meiosis?

A

During Meiosis, cells go from diploid → haploid (by end of MI→)haploid (end of MII)

48
Q

What are the type of cells in which meiosis takes place?

A

Spermatocyte and oocyte

49
Q

Describe spermatogenesis?

A

Germ cell→spermatogonial→spermatogonium→primary spermatocyte→secondary spermatocyte→spermatids→sperm

50
Q

Describe oogenesis?

A

Germ cell→oogonium→primary oocyte→secondary oocyte→fertilization→meiosis 2 is completed→ fertilized egg (zygote)

51
Q

End result of meiosis (comparison of daughter cells with mother cell in terms of number of daughter cells and chromosome makeup)

A

Chromosomal makeup: results half as many as the parent cell for each haploid daughter cell
4 daughter cells

52
Q

Spermatogenesis compared to Oogenesis

A

Spermatogenesis is equal and oogenesis is unequal and produces two polar bodies