Study Group Topic 1 - Basic Genetics

Question 1

Bases
Purines=? rings and bases
Pyrimidines=? rings and bases

Answer 1

Purines have 2 interlocked rings A and G

Pyrmidines have a single ring C and T

Question 2

Number of hydrogen bonds?
A-T
G-C

Answer 2

G-C 3 hydrogen bonds

A-T 2 hydrogen bonds

Question 3

Why is RNA more unstable?

Answer 3

Additional hydroxyl at 2’ position

Question 4

Nucleosome components

Answer 4

2 each of H2A, H2B, H3 and H4

Question 5

Linker DNA histone

Answer 5

H1

Question 6

Euchromatin is…

Answer 6

Extended conformation
Transcriptionally active
Weak binding of H1 histones
Acetylation of nucleosome histones

Question 7

Heterochromatin is…

Answer 7

Condensed
Not expressed
Tight H1 binding

Question 8

cis-acting splicing mutations

Answer 8

Within consensus donor/acceptor
Branch point mutations
Disruption of cis-elements e.g. ESEs, binding of SR’s/hnRNPs

Question 9

Major spliceosome molecules

Answer 9

U1, U2, U4, U5 and U6

Question 10

Minor spliceosome molecules

Answer 10

U11, U12, U4atac, U5 and U6atac

Question 11

Chromosome regions commonly showing variation in constitutive heterochromatin

Answer 11

1qh
9qh
16qh
Yqh

Question 12

9q heterochromatin Inversions

Answer 12

inv(9)(p11q12) third heterochromatin in p arm (10%)

inv(9)(p11q13) all heterochromatin in p arm (0.6%)