Question 19N.2.SL.TZ0.c
| Date | November 2019 | Marks available | [Maximum mark: 7] | Reference code | 19N.2.SL.TZ0.c |
| Level | SL | Paper | 2 | Time zone | TZ0 |
| Command term | Explain | Question number | c | Adapted from | N/A |
Explain how a polypeptide chain is synthesized in a eukaryotic cell.
[7]
a. translation occurs on ribosomes ✔
b. tRNA-activating enzymes attach amino acids to tRNAs ✔
c. small and large ribosome units assemble on mRNA
OR
translation/polypeptide synthesis starts at a start codon ✔
d. each tRNA arriving at the ribosome binds to the A site ✔
e. anticodon «on tRNA» binds to codon «on mRNA» ✔
f. according to complementary base pairing/A with U and G with C ✔
g. ribosome moves along the mRNA / mRNA moves over ribosome ✔
h. t-RNA shifts from the A site to P site/from the P to the E site ✔
i. peptide bond between amino acids «on tRNAs at A and P sites» ✔
j. tRNA released from ribosome at E site ✔
k. cycle repeats with other tRNAs / polypeptide grows as tRNAs bring more amino acids ✔
l. until stop codon on mRNA is reached ✔
m. components are disassembled / polypeptide leaves the ribosome ✔
Accept these points in an annotated diagram.
Do not award any marks for events in transcription.
