storing and using genetic information week 8

Question 1

what is primary structure

Answer 1

sequence of amino acids

Question 2

what is secondary structure

Answer 2

• alpha helix
• beta sheets
• hydrogen bonding

Question 3

what is tertiary structure

Answer 3

final structure of the protein that gives it its functionality

Question 4

what does a nucleotide contain

Answer 4

sugar
base
phosphate group

Question 5

what is a structural feature of the double helix

Answer 5

it has a major groove and a minor groove
usually the major groove that is the site DNA interacts with things e.g. transcription factors
- on major groove roughly 6 base pairs visible

Question 6

what bases are purine

Answer 6

adenine and guanine

- purine has two cyclic rings

Question 7

what bases are pyrimidine

Answer 7

thymine and guanine

Question 8

what type of bonding is between bases

Answer 8

hydrogen

Question 9

what takes place in the nucleus

Answer 9

• replication of DNA

- transcription and so formation of RNA

Question 10

how many chromosomes do humans normally have

Answer 10

46

Question 11

how are chromatins made more accessible for transcription and replication

Answer 11

1. histones can be enzymatically modified (groups added to modify their charge so looser grip on DNA)
2. histones can be displaced by chromatin remodelling complexes
   (reversible processes)

Question 12

what do they mean when they say DNA replication is semi-conservative

Answer 12

one half of each DNA molecule is old the other half is new

Question 13

what unzips the helix

Answer 13

helicase (breaks hydrogen bonds)

Question 14

what direction does replication occur

Answer 14

5’ to 3’

Question 15

what stage of mitosis is most ordered

Answer 15

metaphase

Question 16

what are exons

Answer 16

coding regions

Question 17

what are introns

Answer 17

non-coding regions

Question 18

what is alternative splicing

Answer 18

a set of processes that will alternate the introns or exons that are removed and then how the exons are stitched back together again

Question 19

what is a codon

Answer 19

set of three bases which codes for a particular amino acid

Question 20

how many amino acids are found in proteins

Answer 20

20

Question 21

how many codons can be made from the bases

Answer 21

64 (4^4)

Question 22

what is redundancy of the genetic code

Answer 22

• with the exception of two amino acids all others have more than one codon which encodes them
• so this means you can have slight changes in the DNA sequence and you will still get the same amino acid (redundancy)

Question 23

what are point mutations

Answer 23

change of a nucleotide to another

Question 24

what is mRNA

Answer 24

• messenger RNA

- the actual sequence that codes for protein

Question 25

steps of protein synthesis

Answer 25

in nucleus:
DNA is transcribed to mRNA then alternative splicing occurs
processed RNA leaves nucleus and goes to ribosome in RER or just free floating in cytoplasm and with the help of tRNA and rRNA protein is formed
post translational modifications can them occur

Question 26

what does tRNA do

Answer 26

• major role is to translate mRNA sequence into amino acid sequence
• acts as an adaptor molecule between coded amino acid and mRNA
• so anticodon on tRNA recognises codon

Question 27

what is rRNA

Answer 27

• component of ribosomes
• produced in the nucleus
• transported to cytoplasm where they combine with proteins to form a ribosome