Question 18M.2.HL.TZ2.2
| Date | May 2018 | Marks available | [Maximum mark: 8] | Reference code | 18M.2.HL.TZ2.2 |
| Level | HL | Paper | 2 | Time zone | TZ2 |
| Command term | Outline, State | Question number | 2 | Adapted from | N/A |
State one role of nucleosomes in eukaryotic cells.
[1]
a. help to supercoil/pack DNA in chromosomes
b. help to regulate transcription / gene expression
Outline how Hershey and Chase’s experiment provided evidence for DNA as the genetic material.
[3]
a. experiment is meant to determine whether DNA or protein is the genetic material
b. viruses/bacteriophages grown in radioactive S/S35 which enters the protein coat
c. viruses/bacteriophages grown in radioactive P/P32 which enters the DNA
d. «radioactive» viral DNA entered the bacterial cell during infection
OR
«radioactive» viral protein did not enter the bacterial cell during infection
State one function for a region of DNA that does not code for proteins.
[1]
regulator of gene expression/introns/telomeres/genes for tRNA / rRNA / promoter / enhancer / silencer / site for primer to bind / codes for mRNA primer
Outline the role of the A-site of ribosomes in translation.
[1]
binding/entry of tRNA carrying amino acids/aminoacyl tRNA / charged tRNA / site of transfer of growing polypeptide chains/peptide bond formation
Marks can be awarded to an annotated diagram.
Outline the role of tRNA activating enzymes in translation.
[2]
a. ATP «hydrolysis» provides energy for amino acid attachment ✔
b. they attach a specific amino acid to the (3') end / free CCA of a tRNA ✔
c. they do this repeatedly / they attach amino acid to all of the tRNA molecules that have anticodon corresponding to that amino acid