Lecture 3: The Human Genome Flashcards
1
Q
what is the evolutionary advantage of having deoxyribose
A
loss of the oxygen makes DNA more stable, so it’s not degraded as easily
2
Q
which are the pyrimidine nucleotides
A
cytosine and thymine
3
Q
which are the purine nucleotides
A
adenine and guanine
4
Q
in which direction is DNA “read”
A
5’ to 3’
5
Q
when is DNA completely unravelled
A
during transcription and translation
6
Q
when is DNA folded into chromosomes
A
when cells are trying to divide
7
Q
what is a nucleosome
A
- almost 2 turns of DNA coiled around an octamer of 8 histones
- 2x H2A, H2B, H3 and H4
- nucleosomes join together to make a beads on a chain formation
- H1 histone then allows beads on a chain structure to fold in on itself
8
Q
what are methods of uncoiling DNA
A
- chromatin remodelling complexes, which grab onto the histone and pull DNA apart
- histone modifying enzymes which are acyl, phosphate or methyl groups on histones themselves. Can add or remove these
9
Q
what is epigentics
A
heritable changes in gene function that can be explained by changes to DNA sequence
10
Q
what is Rubinstein-Taybi syndrome
A
- caused by a mutation in histone acetyl-transferases
- has non-specific symptoms
- intellectual disability
- facial abnormalities
- broad thumbs and great toes
