Chromosome and cell division

Question 1

What are DNA molecules packaged in the nucleus as

Answer 1

chromosomes

Question 2

What is the process of DNA condensing

Answer 2

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

Question 3

What is chromatin further condensed to in cell division

Answer 3

Chromsome

Question 4

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

Answer 4

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

Question 5

What is a centromere

Answer 5

Constricted region joining sister chromatids

Question 6

What are the steps in mitosis 
Prophase 
Metaphase
Anaphase 
Telophase 
Cytokines

Answer 6

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

Question 7

What is Kinetochore

Answer 7

When spindle fibres microtubules attach to centromere and pull chromatids apart

Question 8

What are the four divisions of the cell cycle

Answer 8

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

Question 9

Define satellite DNA

Answer 9

tandemly repeating, non-coding DNA

Question 10

Define chromsome

Answer 10

single piece of DNA

Question 11

Define chromatin

Answer 11

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

Question 12

What is the purpose of packaging DNA

Answer 12

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

Question 13

Where is the DNA most condensed

Answer 13

during metaphase

Question 14

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

Answer 14

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

Question 15

Describe the process of chromosomes analysis

Answer 15

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

Question 16

What is Fish (Fluorescent in situ hybridisation)

Answer 16

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

Question 17

Name different fish probes

Answer 17

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

Question 18

Where does meiosis occur

diploid cells turn into

Answer 18

germ cells

Haploid cells

Question 19

How is genetic diversity caused in meiosis

Answer 19

chromosomes are passed or are rearranged

Question 20

what is the process of eggs and sperm formation called

Answer 20

Oogenesis

Spermatogenesis

Question 21

What is continuous Oogenesis or Spermatogenesis

Answer 21

Spermatogenesis

Question 22

Define fertilisation

Answer 22

two haploid cells from diploid cell

Question 23

Where does mitochondria come from

Answer 23

Maternal inheritance

Question 24

What happens in females in early embryo

Answer 24

One of the X chromosomes are inactivated

Question 25

What is FIsH useful for

Answer 25

chromosome translocation and rearrangement

Question 26

What is the end sequence at the telomere

Answer 26

5-TTAGGG-3

Question 27

What is a karyotype

Answer 27

test to determine shape and size of a chromosome

Question 28

Name the major eukaryotic histone

Answer 28

H1 H2A H2B H3 H4