Biochemistry of Nucleic Acids

Question 1

Nucleoside

Answer 1

base and 5 carbon sugar

Question 2

nucleotide

Answer 2

nucleoside and phosphate group

Question 3

purines

Answer 3

adenine and guanine

Question 4

pyrimidines

Answer 4

cytosine, thymine, uracil

Question 5

phosphodiester bonds

Answer 5

form between 3’ OH group and the 5’ triphosphate, links nucleotide together

Question 6

structure of DNA

Answer 6

anti-parallel double helix, one strand is 5’ to 3’, and the other in reverse
sugar-phosphate backbone
base pairs on the inside, held by H bonds

Question 7

5 steps of DNA replication

Answer 7

DNA primer required
Helix unwound by helicase
replication fork with leading and lagging strand
leading synthesised in 5’ to 3’ direction, catalysed by DNA polymerase
Lagging strand is synthesised in okazaki fragments which are then joined by DNA ligase

Question 8

where/how does replication happen?

Answer 8

in eukaryotes, at simultaneous points in the genomes, which speeds up replication
its bidirectional

Question 9

three types of RNA

Answer 9

rRNA
tRNA
mRNA

Question 10

rRNA

Answer 10

combines with proteins to form ribosomes

Question 11

tRNA

Answer 11

carries amino acids to be incorporated into proteins

Question 12

mRNA

Answer 12

carries genetic information for protein synthesis

Question 13

RNA polymerases

Answer 13

multi-subunit complexes which make RNA
Eukaryotes have Pol I, II, III
Pol II synthesises all mRNA

Question 14

8 steps of Transcription