cc5 - nucleic acids

Question 1

monomers of nucleic acids

Answer 1

nucleotides

Question 2

3 components of nucleotides

Answer 2

pentose sugar
organic base
phosphate group

Question 3

2 types of organic base

Answer 3

purine
pyrimidine

Question 4

purine

Answer 4

class of organic bases
double ring structure
includes adenine (A) + guanine (G)

Question 5

pyrimidine

Answer 5

class of organic bases
single ring structure
includes cytosine (C), thymine (T) + uracil (U)

Question 6

structure of DNA nucleotide

Answer 6

deoxyribose
organic base (A, T, C, or G)
phosphate group

Question 7

structure of RNA nucleotide

Answer 7

ribose
organic base (A, U, C, or G)
phosphate group

Question 8

structure of ATP nucleotide

Answer 8

ribose
adenine
3 phosphate groups

Question 9

endergonic reaction

Answer 9

non spontaneous reaction that requires input of energy
e.g: ATP formation

Question 10

exergonic reaction

Answer 10

spontaneous reaction that overall releases energy
e.g: ATP hydrolysis

Question 11

role of ATP

Answer 11

universal energy currency
hydrolysed to release energy
ATP + water = ADP + Pi + energy

Question 12

complementary base pairing

Answer 12

how H bonds form between complementary purine + pyrimidine bases
two bonds between A and T (or U)
three bonds between G and C

Question 13

structure of DNA

Answer 13

double stranded polymer of nucleotides twisted to form double helix
nucleotides joined by phosphodiester bonds
H bonds form between complemtary base pairs, A and T, C and G
anti parallel strands

Question 14

why strands of DNA double helix described as antiparallel

Answer 14

complementary strands run parallel but in opposite direction
5’ to 3’ and 3’ and 5’

Question 15

structure of RNA

Answer 15

single stranded polymer of nucleotides
nucleotides joined by phosphodiester bonds
H bonds form between complementary base pairs
A and U, C and G

Question 16

compare DNA + RNA

Answer 16

DNA:
double stranded
long chain of nucleotides
contains deoxyribose sugar
contains bases A T C G
storage of genetic information
phosphodiester bonds join nucleotides
RNA:
single stranded
shorter chain of nucleotides
contains ribose sugar
contains bases A U C G
role in protein synthesis
phosphodiester bonds join nucleotides

Question 17

3 types of RNA found in cells

Answer 17

transfer RNA (tRNA)
messenger RNA (mRNA)
ribosomal RNA (rRNA)

Question 18

function of tRNA

Answer 18

carries specific amino acids to ribosomes

Question 19

structure of tRNA

Answer 19

80 nucleotides
single helix
clover leaf shape
anticodon on one end, amino acid binding site on other

Question 20

function of mRNA

Answer 20

carries genetic information form nucleus to ribosomes for protein synthesis

Question 21

structure of mRNA

Answer 21

2000 nucleotides
single helix
unstable

Question 22

function of rRNA

Answer 22

associated with proteins in cytoplasm to form ribosomes

Question 23

structure of rRNA

Answer 23

1800 to 500p nucleotides
two subunits: one large, one small

Question 24

semi-conservative replication

Answer 24

replication of DNA to produce 2 new DNA molecules which both contain one new strand + one old strand from of DNA molecule

Question 25

role of DNA helicase in semi-conservative replication

Answer 25

catalyses unzipping of double stranded DNA into 2 single strands, each of which acts as a template