Chromosomes, cell division, meiosis and chromsoome abnormalities Flashcards Preview

Principles of disease JK > Chromosomes, cell division, meiosis and chromsoome abnormalities > Flashcards

Flashcards in Chromosomes, cell division, meiosis and chromsoome abnormalities Deck (26):
1

Telomere

Protect ends and prevent erosion

2

Centromere

Join sister chromosomes which are held together with cohesins until anaphase
Site of kinetochore and non coding satellite DNA
Repeats 5' - TTAGGG-3' (10-15kb)

3

Kinetochore

Protein complex on centromere where microtubule attaches

4

How to get over shortening chromosomes

Enzyme telomerase adds DNA using RNA as lose bases after every mitosis

5

S phase

replication

6

G1

Cell growth

7

G2

Cell divide

8

Interphase

G1, S , G2

9

M phase

Prophase, metaphase, anaphase , telophase and cytokinesis

10

Prophase

Spindle from centriole and nuclear membrane breakdown

11

Metaphase

Chromosomes replicated and align on M plate where spindle attaches

12

Anaphase

Sister chromosomes separate and move to opposite poles

13

Telophase

Reform nuclear membrane

14

Cytokinesis

Cytoplasm separates

15

Nucleosome

Negative DNA and positive histone protein => solenoid

16

Why package DNA?

DNA neutralised and takes up less space
Inaccessible until required

17

Metacentric

Similar p and q length

18

Submetacentric

Slightly offset

19

Acrocentric

Q much larger than p and no coding DNA

20

FISH

Look for specific area of interest in karyotype
Label with fluorescent dye

21

What can FISH be used for

Centromeric - chromosome number
Telomeric, unique sequence or whole chromosome differences

22

Meiosis

Diploid => haploid
Recombination occurs => genetic diversity

23

Oogenesis

Egg formation 10-50 years
20-30 mitoses and 1 egg with 3 polar bodies

24

Spermatogenesis

60-65 days so more chance of mutation
4 spermatids and 100-200 million per ejaculate

25

Do mitochondria come from only mum or dad?

Mum

26

What is a barr body?

X inactivation occurs in females and the barr body is the inactive x chromosome