Basics

Question 1

How is DNA hereditary?

Answer 1

Double helix allows for copying mechanism/ permutations leads to precise sequences of genetic code

Question 2

How can the human karyotype be observed?

Answer 2

Complete set of chromosomes in a species or in an individual organism, stained with Giemsa

Question 3

What is the structure of the human karyotype?

Answer 3

23 chromosomes, 46 chromosomes in diploid cells, 22 autosomes, 1 sex

Question 4

How is DNA packed?

Answer 4

Nucleosome- bead and string around histone proteins/ chromatin formed

Question 5

What are histones?

Answer 5

Small, positively-charged DNA-binding proteins/ octamer with tails/ highly conserved in evolution

Question 6

How is chromosome structure dynamic?

Answer 6

Interphase- G1, S, G2/ Mitosis- PMAT= temporal
Uncoiling to enable high-level gene expression= spatially
Gene expression/ DNA replication and repair

Question 7

What are chromatin-remodelling complexes?

Answer 7

Locally reposition the DNA wrapped around nucleosome (ATP dependent)

Question 8

How are histones modified?

Answer 8

Tails reversibly chemically modified to make chromatin less or more accessible- methylation/ acetylation/ phosphorylation

Question 9

What is the structure of a centromere?

Answer 9

Highly repetitive sequence, can stretch over megabases, bound by a pair of large protein complexes (kinetochore) microtubules attach in metaphase

Question 10

What are telomeres?

Answer 10

Specialised end-structures, long repetitive repeats form T-loop that folds back on itself, protects from natural cellular exonucleases to maintain chromosomal integrity

Question 11

What are cohesions?

Answer 11

Cohesion rings tie together sister chromatids in each duplicated chromosome, broken in anaphase