Nucleic Acids

Question 1

What’s the role of nucleic acids

Answer 1

To store, transmit and express genetic information

Question 2

4 differences of DNA and RNA

Answer 2

DNA- deoxyribose whilst RNA is just ribose
In DNA A pairs with T but in RNA A pairs with U
DNA-double stranded whilst RNA single stranded
RNA is used for protein synthesis and regulation

Question 3

What are the 3 components of a nucleotide

Answer 3

Phosphate sugar
pentose sugar
Nitrogenous base

Question 4

What does A pair with in RNA

Answer 4

U

Question 5

What does A pair with in DNA

Answer 5

T

Question 6

What does C pair with

Answer 6

G

Question 7

What bond is between the pairs

Answer 7

Hydrogen bonds

Question 8

Give 3 characteristics of DNA’s structure

Answer 8

Double helix
antiparallel strands 5’ to 3’ and 3’ to 5’
Complementary base pairing maintaining helical structure

Question 9

What are the 3 types of RNA

Answer 9

mRNA
tRNA
rRNA

Question 10

What is the role of messenger RNA (mRNA)

Answer 10

Carries genetic information from DNA to ribosomes

Question 11

What is the role of transfer RNA (tRNA)

Answer 11

Brings amino acids to ribosome during translation

Question 12

What is the role of ribosomal RNA (rRNA)

Answer 12

Component of ribosome : catalyses peptide bond formation

Question 13

True or false : DNA replication is semi-conservative

Answer 13

True

Question 14

What are the 3 key enzymes involved in DNA replication

Answer 14

Helicase
DNA polymerase
Ligase

Question 15

What’s the role of helicase

Answer 15

Unwinds DNA helix

Question 16

What’s the role of DNA polymerase

Answer 16

adds nucleotides to the new strand

Question 17

What’s the role of ligase

Answer 17

Joins Okazaki fragments on lagging strand

Question 18

What are okazaki fragments

Answer 18

Short DNA sequences that are synthesised discontinuously on the lagging strand in DNA replication

Question 19

True or false : transcription is DNA–> RNA (in nucleus)

Answer 19

True

Question 20

True or false Translation is RNA–> Protein (in cytoplasm)

Answer 20

True

Question 21

What happens in transcription

Answer 21

RNA polymerase synthesises mRNA from DNA template

Question 22

What happens during translation

Answer 22

Ribosomes reads mRNA
tRNA delivers amino acids to build protein

Question 23

What are codons

Answer 23

Sequences of 3 nucleotides (triplets) on mRNA that correspond to specific amino acids

Question 24

2 characteristics of the genetic code

Answer 24

Universal and degenerate

Question 25

Define nucleoside

Answer 25

A molecule consisting of 5-carbon sugar and a nitrogenous base no phosphate group

Question 26

Why is DNA more stable than RNA (2 reasons)

Answer 26

DNA contains deoxyribose which lacks 2 OH- group round in DNA - less reactive Double stranded so more protected

Question 27

What does heating do to DNA

Answer 27

Breaks H-bonds - strands separate

Question 28

Which are purine bases found in DNA

Answer 28

Adenine and guanine

Question 29

Out of AT and CG which have more hydrogen bonds

Answer 29

G-C (3pairs)