Chromosome and cell division Flashcards Preview

Medicine Term One > Chromosome and cell division > Flashcards

Flashcards in Chromosome and cell division Deck (28):
1

What are DNA molecules packaged in the nucleus as

chromosomes

2

What is the process of DNA condensing

1. DNA wrap itself around histone proteins
2. This furthers condenses by packaging into units called nucleosomes
3. Further wrapping of Nucleosomes
4. Chromatin formed

3

What is chromatin further condensed to in cell division

Chromsome

4

Chromosomes are divided between euchromatin and heterochromatin what is the difference between them

Heterochromatin = Condensed structure,
Silenced genes
Euchromatin = Open structure, Active genes

5

What is a centromere

Constricted region joining sister chromatids

6

What are the steps in mitosis
Prophase
Metaphase
Anaphase
Telophase
Cytokines

Chromosomes condense
Nuclear membrane disappears
Spindle fibres form from the centriole

Chromosomes aligned at the equator of the cell
Attached by microtubule fibres to each centriole


Sister chromatids separate at centromere = kinetochore
Move to opposite ends of cell

New nuclear membranes form
Each cell contains 46 chromosomes (diploid)


Cytoplasm separates
Two new daughter cells

7

What is Kinetochore

When spindle fibres microtubules attach to centromere and pull chromatids apart

8

What are the four divisions of the cell cycle

G1 - cell growth
S - DNA replication
G2 - Cell growth
M - Mitosis

9

Define satellite DNA

tandemly repeating, non-coding DNA

10

Define chromsome

single piece of DNA

11

Define chromatin

name given to the mixture of DNA, proteins and RNA that package DNA within the nucleus.

12

What is the purpose of packaging DNA

Neutralise DNA as histone has a positive charge
Takes up less space
Condensed until required

13

Where is the DNA most condensed

during metaphase

14

What is the lengths of chromosome and what are they dependant on

One short arm - p arm
One long arm - Q arm
Centromere

15

Describe the process of chromosomes analysis

separate RBC
Culture
Colchine added
Separate WBC
hypotonic solution added
cells dropped on to slide and stained
then KARYOTYPE


16

What is Fish (Fluorescent in situ hybridisation)

Probe DNA labelled with coloured dye and should bind to complimentary part chromosome of interest if its present

17

Name different fish probes

Centromeric probes - chromsome number
Telomeric probes - check child mental retardation
Whole chromosome probes -

18

Where does meiosis occur
diploid cells turn into

germ cells
Haploid cells

19

How is genetic diversity caused in meiosis

chromosomes are passed or are rearranged

20

what is the process of eggs and sperm formation called

Oogenesis
Spermatogenesis

21

What is continuous Oogenesis or Spermatogenesis

Spermatogenesis

22

Define fertilisation

two haploid cells from diploid cell

23

Where does mitochondria come from

Maternal inheritance

24

What happens in females in early embryo

One of the X chromosomes are inactivated

25

What is FIsH useful for

chromosome translocation and rearrangement

26

What is the end sequence at the telomere

5-TTAGGG-3

27

What is a karyotype

test to determine shape and size of a chromosome

28

Name the major eukaryotic histone

H1 H2A H2B H3 H4