Chromosomes, Cell Division, Meiosis and Chromosome Abnormalities Flashcards Preview

Principles of Disease > Chromosomes, Cell Division, Meiosis and Chromosome Abnormalities > Flashcards

Flashcards in Chromosomes, Cell Division, Meiosis and Chromosome Abnormalities Deck (91)
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1

Describe the structure of a chromosome

Linear chromosome
Telomere
Centromere
Heterochromatin
Euchromatin

2

Describe the features of telomeres

Have 5’-TTAGGG-3’ repeats
Hundreds of copies being present at the end of the chromosomes

3

How long are human telomeres

10-15 kb

4

How many base pairs do telomeres lose during mitosis

About 100

5

What are the 4 phases of the cell cycle

G1 -gap phase
S
G2 - gap 2
M - mitosis

6

What can occur after mitosis

Cells may cease division
Others may begin the cell cycle again

7

What happens in G1

Cell grows

8

What happens in G2

Cell prepares to divide

9

What happens in S

Cell replicates

10

What happens in M

Cell divison

11

How long does G1 last

10-12 hours

12

How long does S last

6-8 hours

13

How long does G2 last

2-4 hours

14

How long does M last

1-2 hours

15

How many phases of mitosis are there

5

16

Name the phases of mitosis

Prophase
Metaphase
Anaphase
Telophase
Cytokinesis

PMAT C

17

What occurs in prophase

Chromosomes condense
Nuclear membrane disappears
Spindle fibres form from the centriole

18

What occurs in metaphase

Chromosomes are aligned at the equator of the cell
They are attached by fibres to each centriole
This is the maximum condensation of the chromosome

19

What occurs in anaphase

Sister chromatids separate longitudinally at the centromere and move to opposite ends of cell

20

What occurs in telophase

New nuclear membranes form

21

How many chromosomes are there in a diploid cell

Each diploid cell contains 46 chromosomes

22

What occurs in cytokineis

Cytoplasm separates
Two new daughter cells are formed

23

What are centromeres

Constricted regions which join the sister chromatids together (middle part of chromosome)

24

Describe centromeres

They have repetitive DNA sequences called satellite DNA
Are the site of kinetochore

25

What is a kinetochore

The kinetochore is the protein complex which binds to microtubules
It is required for chromosome separation during cell division

26

What is interphase

The phases:
G1
S
G2

27

What is heterochromatin

Condensed structure in silenced genes

28

What is euchromatin

Open structure in active genes

29

How many base pairs are there in DNA

About 3 billion

30

How many genes are in DNA

20-30,000 genes