Theme 3 - human genome

Question 1

what type of chromatin predominates in the nucleus

Answer 1

euchromatin

Question 2

where is ribosomal RNA translated

Answer 2

nucleolus

Question 3

how is information trafficked in and out of the nucleus

Answer 3

via pore on the envelope

Question 4

what are the three functions of DNA

Answer 4

encode all information required to make an organism, replicate accurately and must allow for beneficial mutations to be selected (for evolution)

Question 5

what is the definition of genetics

Answer 5

study of heredity - process by which characteristics are passed from parent to offspring

Question 6

what is a gene

Answer 6

unit of biological information that encodes a specific protein or regulatory molecule

Question 7

what is precision medicine

Answer 7

new approach to treatment that takes into account individual variability in genes, environment and lifestyle

Question 8

when was the first human genome published?

Answer 8

2001

Question 9

how long did first genome sequencing take and how much did it cost

Answer 9

13 years and cost 3 billion dollars

Question 10

how much does genome sequencing now cost and how long does it take

Answer 10

takes a few days and costs $5000

Question 11

how many bases make up DNA and what % of these are repeated sequences?

Answer 11

3.2 billion bases and 50% of this is repeated

Question 12

what % of DNA is protein coding?

Answer 12

1.5%

Question 13

how many genes does the genome contain and how many of these are essential for life?

Answer 13

contains 20,000 genes and 300-400 of these are essential for life

Question 14

what gives genes complexity?

Answer 14

spatial and temporal regulation

Question 15

what % are genes identical?

Answer 15

99.9%

Question 16

how many SNPs do we have in the genome?

Answer 16

3 million

Question 17

around how many disease associated SNPs does each individual have?

Answer 17

50-100

Question 18

give two reasons why a SNP may not cause disease?

Answer 18

we are diploid and therefore have two copies of each gene or the SNP doesn’t cause change to the protein

Question 19

what is polygenic disease and give an example

Answer 19

multifactorial disease eg environment and genes together for example CVD

Question 20

what drug does highly active cyp2C9 affect?

Answer 20

warfarin - high levels of cyp2c9 will metabolise warfarin faster

Question 21

what % of prescribed drugs have no effect?

Answer 21

40%

Question 22

what three things make up a nucleotide?

Answer 22

sugar, phosphate and a base

Question 23

what bonds are made between complementary base pairs?

Answer 23

weak hydrogen bonds

Question 24

what is the bonding in the backbone of DNA?

Answer 24

strong covalent

Question 25

which type of bond links nucleotides together to make a polar molecule

Answer 25

phosphodiester bonds

Question 26

what are the five steps of supercoiling DNA into a mitotic chromosome?

Answer 26

2nm short region of DNA, beads on a string chromatin 11nm, chromatin packed into a nucleosome 30nm, chromatin fibres folded into loops 700nm, entire mitotic chromosome 1400nm

Question 27

what state nm state is chromatin in most of the time?

Answer 27

30nm

Question 28

what is the first level of DNA folding?

Answer 28

DNA folded round core histones to form a nucleosome

Question 29

how many nucleotide pairs of DNA are found in one histone?

Answer 29

200

Question 30

what charge to histones have?

Answer 30

positive

Question 31

what does the second level of DNA folding require?

Answer 31

an extra histone - H1

Question 32

what are the regular histone proteins required for folding

Answer 32

H2A, H2B, H3 and H4

Question 33

what histone is required to make the 30nm fibre?

Answer 33

H1

Question 34

what two methods regulate condensed chromatin to de condensed chromatin?

Answer 34

chromatin remodelling complexes and histone modifying enzymes

Question 35

what are chromatin remodelling complexes dependent on?

Answer 35

ATP

Question 36

how do histone modifying enzymes work?

Answer 36

they change the structure of the histones by addition or removal of acetyl/phosphate or methyl groups

Question 37

what does supercoiling of the beta globing gene lead to?

Answer 37

severe anemia

Question 38

what are heritable changes in gene function that cannot be explained by changes in a DNA sequence?

Answer 38

epigenetic

Question 39

how can rubenstein taybi syndrome be characterised?

Answer 39

mutation in histone acetyl transferases which leads to non specific symptoms - mental retardation, facial abnormalities, broad thumbs and big toes

Question 40

what is the incidence of rubenstein taybi syndrome?

Answer 40

1 in 100,000