IB Biology HL D1.2 Protein synthesis questions

Exam-style multiple choice and written questions with full markschemes. Check multiple choice answers straight away, or type, photograph or draw a written answer and get it marked.

Type
Multiple choiceWritten
Difficulty
EasyMediumHard

Question 1

Multiple choiceEasy1 mark

A cell contains gene X, which codes for an enzyme. Transcription of gene X is switched off. What is directly prevented?

Show answer and explanation

Answer: A. Transcription uses a gene’s DNA sequence to synthesize mRNA. If transcription of gene X is switched off, new mRNA from that gene is not produced; translation uses mRNA to synthesize a polypeptide.
B: confuses transcription with translation by using DNA directly as the template for polypeptide synthesis.
C: confuses gene expression with DNA replication; switching off transcription does not itself prevent DNA copying.
D: confuses transcriptional control with translational control; existing mRNA can still be translated.
Remember: transcription makes mRNA; translation makes a polypeptide from mRNA.

Question 2

Paper 2Easy5 marks

Researchers examine mature mRNA produced from the same gene in two cell types. The exons present in each mRNA are shown.

Cell typeExons in mature mRNA
X1, 2, 4
Y1, 3, 4
(a)

Identify the exon present in the mRNA from cell type X but absent from the mRNA from cell type Y.

[1]
(b)

State the two exons present in both mRNAs.

[2]
(c)

Using the table, explain how this gene can code for different polypeptides.

[2]

The best questions are still waiting

Unlock every question in this topic, then type, photograph or draw your answer and have it marked against the markscheme. Find out where you are dropping marks.

Unlock all questionsCompare Student and Student Plus