Biochemistry of nucleic acids, gene regulation and proteins

Question 1

what is the structure of a nucleoside?

Answer 1

base and 5 carbon sugar

Question 2

what is the structure of a nucleotide?

Answer 2

nucleoside + phosphate group

Question 3

what is the structure of purines?

Answer 3

adenine and guanine (double ring)

Question 4

what is the structure of pyrimidines?

Answer 4

cytosine, thymine, uracil (longest name = shortest structure)

Question 5

what are phosphodiesterase bonds?

Answer 5

form between 3’ OH group and 5’ triphosphatase - link nucleotides

Question 6

what are the 4 bases in DNA molecules?

Answer 6

ACGT

Question 7

what are the 4 bases in RNA molecules?

Answer 7

ACGU

Question 8

what is the nomenclature for adenine?

Answer 8

adenosine

Question 9

what is the nomenclature for cytosine?

Answer 9

cytidine

Question 10

what is nomenclature for guanine?

Answer 10

guanosine

Question 11

what is the nomenclature for thymine?

Answer 11

thymidine

Question 12

where are nucleotides added to?

Answer 12

the free 3’ end

Question 13

what must strands be in order for nuclotides to be added?

Answer 13

anti-parallel

Question 14

what is formed between a 3’ OH and a 5’ triphosphate?

Answer 14

a phosphidiesterase bond

Question 15

what are the base pairs inside DNA structure held together by?

Answer 15

hydrogen bonds

Question 16

what is DNA replication catalysed by?

Answer 16

DNA polymerase

Question 17

what does DNA replication require to start replication?

Answer 17

RNA primer

Question 18

what are the 3 types of RNA?

Answer 18

rRNA, tRNA and mRNA

Question 19

what is the role of tRNA?

Answer 19

combines with proteins to form ribosomes

Question 20

what is the role of tRNA?

Answer 20

carries amino acids to be incorporated into protein

Question 21

what is the role of mRNA?

Answer 21

carries genetic information for protein synthesis

Question 22

what can be created is wrong nucleotides are incorporated?

Answer 22

mutations

Question 23

DNA polymerase has 3’ -> 5’ what activity?

Answer 23

exonuclease

Question 24

what does exonuclease activity do?

Answer 24

removes incorrect nucleotide

Question 25

what are RNA polymerases?

Answer 25

multi-subunit complexes which make RNA

Question 26

what are the 3 types of RNA polymerases that eukaryotes have?

Answer 26

Pol I, Pol II and Pol III

Question 27

what Pol synthesizes mRNA?

Answer 27

Pol II

Question 28

what do RNA polymerases do?

Answer 28

bind promoters for transcription to begin

Question 29

what is initiation in transcription?

Answer 29

selection of first nucleotide of growing RNA

Question 30

what is elongation in transcription?

Answer 30

addition of further nucleotides to RNA chain in the 5’ -> 3’ direction

Question 31

what is termination in transcription?

Answer 31

release of finished mRNA

Question 32

what are 3 steps to going from premature -> mature RNA?

Answer 32

splice out introns (non-coding regions)
add poly-adenosine tail
add 5’ cap

Question 33

what are 4 steps of translation?

Answer 33

initiation
elongation
peptide bond formation and translocation
termination

Question 34

what are 4 examples of post-translational modifications?

Answer 34

glycosylation
disulphide bonds
folding/assembly of multi-subunit proteins
specific proteolytic cleavage

Question 35

what are the 3 tRNA binding sites?

Answer 35

peptidyl site
acceptor site
exit site

Question 36

what are point mutations?

Answer 36

change in single base in DNA

Question 37

what are missense mutations?

Answer 37

results in change of amino acid sequence

Question 38

what are nonsense mutations?

Answer 38

creates new termination codon

Question 39

what are silent mutations?

Answer 39

no change of amino acid sequence

Question 40

what are frameshift mutations?

Answer 40

addition or deletion of 1 or 2 bases which changes the reading frame of translation