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Flashcards in Cell cycle Deck (42)
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1

What is the longest phase of the cell cycle?

Interphase

2

What parts is interphase divided into?

G1 (cell contents replicated. Increase in size.)
S- (DNA REPLICATION)
G2 - (more cell growth)

3

What is the G0 stage?

A period where the cell stops replicating as there are no signals sent for division. This can be temporary or permanent and usually occurs during G1.

4

How many checkpoint are there during interphase?

3

5

What occurs at the checkpoint to allow the cycle to continue?

The proteins controlling the checkpoints are phosphorylated

6

What occurs if checkpoint proteins are not phosphorylated?

The cell either repairs the damage or undergoes apoptosis

7

When does the 4th checkpoint occur?

Before the chromosome spilt (during metaphase) to ensure the chromosomes are correctly aligned

8

What are the 5 stages of Mitosis?

Prophase, metaphase, anaphase, telophase and cytokinesis

9

What is the structure of a chromosome??

They consist of a short (p) arm and a long (q) arm and are held together by a centromere

10

What are the 4 chromosome structures due to centromere placement?

Metacentric, submetacentric, Acrocentric and telocentric

11

What occurs in prophase?

Nuclear Membrane disappears, chromosomes form

12

What happens in prometaphase?

Spindle fibres bind to centromeres, nuclear Membrane has completely disappeared

13

What happens in metaphase?

Replicated chromosomes align at the metaphase plate

14

What happens in anaphase?

Microtubules spindle pulls chromosomes apart to opposite poles

15

What happened in telophase?

Spindle disappeared, nuclear envelope reforms and a cleavage furrow forms as the cells start to be cleaved

16

What are homologous chromosome?

Chromosomes that have the same genes in the same loci, but different forms of the genes (alleles)

17

What does meiosis results in?

4 non-identical haploid cells

18

What stage is present in mitosis but not meiosis?

Prometaphase

19

What occurs in Prophase 1 of meiosis?

Synopsis occurs where the homologous chromosome pair up and crossing over occurs between non sister chromatids to form recombinant DNA

20

What is the importance of crossing over?

It gives genetic variation

21

What are the points at which crossing over occurs called?

Chiasmata

22

How is metaphase 1 in meiosis different?

The homologous pairs (bivalents) line up on the metaphase plate and there is independent assortment of bivalents

23

How is metaphase II different from metaphase I?

There is independent assortment of CHROMATIDS instead of BIVALENTS

24

What is the consequence of meiosis?

It allows the chromosome number to remain constant from generation to generation

25

What is spermatogenesis?

Cell division(meiosis) to make male gametes

26

What is the time length of spermatogenesis?

60 days

27

Outline spermatogenesis

The spermatogonium (diploid) divides by mitosis to make primary spermatocytes (diploid). These then undergo meiosis I to produce 2 secondary spermatocyte each which then undergoes meiosis II so that 4 spermatids are produced that develop into sperm cells

28

What is oogenesis?

Cell division by meiosis to produce female gametes

29

Outline oogenesis

The Oogonium divides by mitosis to produce primary oocytes. The primary oocytes undergo meiosis to produce 1 mature ovum and 3 polar bodies.

30

How long does oogensis take?

12-50 years