nucleic acids - exam questions

Question 1

ADP binds with an inorganic phosphate to make ATP. Name this type of reaction.

Answer 1

condensation reaction

Question 2

suggest why the cells do not need to be crushed before adding detergent

Answer 2

WBCs do not have cell walls to break open

Question 3

DNA Helicase:

Answer 3

unzips dna molecule breaking h2 bonds between the complementary bases separating the two strands

Question 4

the results from the investigation show that DNA must be hereditary. explain how they show this:

Answer 4

• DNA transforms into the type R cells
• no other molecules have any effect
• so DNA must be the molecule that carries info from one generation to the next

Question 5

evaluate the ethics in the investigation:

Answer 5

• animals harmed but change to virulence of the bacterium is easily measurable so valuable research is not possible without this

Question 6

explain the meaning of the following terms:
triplet code

Answer 6

each amino acid is coded for by three bases

Question 7

explain the meaning of the following terms:
non-overlapping

Answer 7

• each base is only used once in a triplet
• AAT + AAC + CAG + TTT give 4 distinct triplets/codes

Question 8

Which of the following statements, A to D about DNA replication is correct?

Answer 8

• the proportion of adenine in a nucleic acid will always equal the proportion of guanine

Question 9

twenty different amino acids are commonly used for protein synthesis. this would need only 20 different base combinations. explain the uses of the remaining 44 combinations.

Answer 9

• several triplet codons code for one amino acid, some are used as start/stop codons

Question 10

explain the meaning of the following terms:
degenerate

Answer 10

more than one code can be used for a particular amino acid eg AAT and AAC code for levine