Nucleotides and Nucleic Acids

Question 1

What are the three components of a nucleotide?

Answer 1

Phosphate group. Pentose sugar. Nitrogenous base.

Question 2

What is the difference between RNA and DNA nucleotides?

Answer 2

DNA: deoxyribose, bases A T G C. RNA: ribose, bases A U G C.

Question 3

What bases are purines?

Answer 3

Adenine and guanine.

Question 4

What bases are pyrimidines?

Answer 4

Cytosine, thymine, uracil

Question 5

What type of sugar is found in DNA?

Answer 5

Deoxyribose

Question 6

What type of sugar is found in RNA?

Answer 6

Ribose

Question 7

What bond links nucleotides in a polynucleotide chain?

Answer 7

Phosphodiester bond.

Question 8

What bond is formed and broken in the synthesis and breakdown of
polynucleotides?

Answer 8

Formed by condensation. Broken by hydrolysis.

Question 9

What are the components of ATP and ADP?

Answer 9

Adenine, ribose, 2 or 3 phosphate groups.

Question 10

What are the components of ATP and ADP?

Answer 10

Adenine

Question 11

What is the function of ATP?

Answer 11

Energy carrier molecule.

Question 12

What is complementary base pairing?

Answer 12

A pairs with T (2 bonds). G pairs with C (3 bonds).

Question 13

How many hydrogen bonds form between A and T? Between G and C?

Answer 13

A-T: 2 hydrogen bonds. G-C: 3 hydrogen bonds.

Question 14

What is the structure of DNA?

Answer 14

Double helix of two antiparallel polynucleotide strands held by hydrogen bonds.

Question 15

What does antiparallel mean in DNA?

Answer 15

One strand runs 5’ to 3’, the other 3’ to 5’.

Question 16

What is meant by semi-conservative replication?

Answer 16

Each new DNA molecule has one original and one new strand.

Question 17

What does DNA helicase do?

Answer 17

Unzips DNA by breaking hydrogen bonds.

Question 18

What does DNA polymerase do?

Answer 18

Adds complementary DNA nucleotides to new strand.

Question 19

What causes mutations during DNA replication?

Answer 19

Random spontaneous base changes during replication.

Question 20

What is meant by the triplet nature of the genetic code

Answer 20

Each amino acid is coded by a sequence of 3 bases.

Question 21

What is meant by the triplet nature of the genetic code?

Answer 21

Multiple codons can code for the same amino acid.

Question 22

What does it mean that the genetic code is non-overlapping?

Answer 22

Each base is only read once in a codon.

Question 23

What does it mean that the genetic code is universal?

Answer 23

Same codon codes for same amino acid in all organisms.

Question 24

What is the role of mRNA?

Answer 24

Carries genetic code from DNA to ribosome.

Question 25

What is the role of tRNA?

Answer 25

Transfers specific amino acids to ribosome during translation.

Question 26

What is transcription?

Answer 26

Structural component of ribosomes, catalyses peptide bond formation.

Question 27

What is the role of rRNA?

Answer 27

DNA is used to make mRNA.

Question 28

What is translation?

Answer 28

mRNA is used to assemble amino acids into polypeptide.