Lecture 5

Question 1

How is DNA packed?

Answer 1

Packed into compact units called chromosomes

Question 2

What is a chromosome?

Answer 2

A long stand of DNA wound round structural proteins called histones

Question 3

What is the long arm of chromatin called?

Answer 3

Q arm

Question 4

What is the short arm of chromatin called?

Answer 4

P arm

Question 5

Which are the dark and light sections?

Answer 5

Dark = Heterochromatin - genetically inactive 
Light = Euchromatin - Active

Question 6

What are the ends of the chromosome called?

Answer 6

Telomeres

Question 7

Describe Mitosis (Somatic cells)

Answer 7

Interphase - G1, S and G2
M Phase - 1. Prophase - chromatin condenses to chromosomes
2. Prometaphase
3. Metaphase - Nuclear membrane disappears, chromosomes align at middle
4. Anaphase - Sister chromatids separate
5. Telophase
6. Cytokinesis

Question 8

Describe meiosis (Germline cells)

Answer 8

Meiosis 1 - Half number of chromosomes
Meiosis 2 - Splits sister chromatids
Recombination can occur during meiosis 1

Question 9

What is downs syndrome

Answer 9

Trisomy 21

Question 10

What can non-homologous chromosomes do?

Answer 10

Swap genetic material which may lead to disease e.g. 3 and 15