DNA and RNA structure and function

Question 1

DNA

Answer 1

Deoxyribonucleic acid

Stores genetic information

Question 2

RNA

Answer 2

Ribonucleic acid

Carries genetic information from the DNA to ribosomes

Question 3

Ribosome

Answer 3

Formed from rRNA and proteins

Question 4

DNA & RNA

Answer 4

Polymers

Chains of nucleotides called polynucleotides

Question 5

Nucleotide parts

Answer 5

Phosphate, nitrogenous base, pentose sugar

Ester bond between phosphate and pentose

Glycosidic bond between base and pentose

Question 6

Components of DNA nucleotide

Answer 6

Pentose sugar
Phosphate
Organic group - ATCG

Question 7

Components of RNA nucleotide

Answer 7

Ribose
Phosphate
Organic group - AUCG

Question 8

Difference between DNA and RNA nucleotide

Answer 8

DNA has deoxyribose, RNA has ribose

DNA has thymine, RNA has uracil

Question 9

2 nucleotides

Answer 9

Link together by a condensation reactions with a phosphodiester bond linking them

Question 10

Many nucleotides

Answer 10

Link together by many condensation reactions with many phosphodiester bonds liking them in a sugar-phosphate backbone.

Question 11

DNA molecule

Answer 11

Double helix with 2 polynucleotide chains held together by hydrogen bonds between specific complementary base pairs

Anti-parallel

Question 12

Triplet

Answer 12

Sequence of 3 bases in the DNA

Each triplet codes for a particular amino acid

Any changes to the triplet (gene mutations) can lead to different amino acids appearing in the polypeptide chain and can result in non-functional proteins/enzymes

Question 13

Structure of RNA

Answer 13

Short polypeptide chain

Single-stranded

Question 14

rRNA

Answer 14

Found in a ribosome along with protein

Question 15

mRNA produced

Answer 15

Produced by transcription in the nucleus and then moves to the cytoplasm where it takes part in translation

Question 16

tRNA

Answer 16

Involved in the process of translation

Question 17

Structure of mRNA

Answer 17

Copy of a single gene in the DNA - has complementary bases and is single-stranded, straight chain

Relatively unstable molecule as it has no hydrogen bonds in its structure

Question 18

Why is the actual number of amino acids likely to be less

Answer 18

Introns (non-coding) & stop codons

Question 19

Codon

Answer 19

Sequence of 3 bases in the mRNA

Question 20

Role of mRNA in protein synthesis

Answer 20

Copy of genetic info in DNA of 1 gene so is small enough to pass through nuclear pores into the cytoplasm

Question 21

Structure of tRNA

Answer 21

Single stranded but they coil up to a clover-leaf shape that is held together by hydrogen bonds, making it more stable

2 important regions - amino acid binding site that picks up specific amino acids and an anticodon at other end that is complementary to codon

Question 22

Relationship between codons and anticodons

Answer 22

Complementary

Question 23

Relationship between anticodons and triplets

Answer 23

Same except DNA has thymine, RNA has uracil

Question 24

Bond between amino acids

Answer 24

Peptide

Question 25

TRNA involved

Answer 25

In process of translation

Carry particular amino acid to the ribosome to be added to the growing peptide chain

Question 26

Explain how tRNAs are specific to particular amino acid

Answer 26

Matches with anticodons

Question 27

DNA summary

Answer 27

Deoxyribose sugar, ATCG, 2 strands

V long, hydrogen bonds, double-helix

Triplets, v stable lifespan, site of action is nucleus

Question 28

mRNA summary

Answer 28

Ribose sugar, AUCG, 1 strand

V short, no hydrogen bonds, single-stranded

Codon, v unstable lifespan, site of action is nucleus & cytoplasm

Question 29

tRNA summary

Answer 29

Ribosome sugar, AUCG, 1 strand, v short

Hydrogen bonds, clover-leaf shape, anticodon

Some stability in lifespan, site of action is cytoplasm