Practice D2.2 Gene expression (HL) with authentic IB Biology exam questions for both SL and HL students. This question bank mirrors Paper 1A, 1B, 2 structure, covering key topics like cell biology, genetics, and ecology. Get instant solutions, detailed explanations, and build exam confidence with questions in the style of IB examiners.
Paper
Level
Question 1
SLPaper 1A
What does transcription allow a cell to do?
Question 2
SLPaper 1A
Transcription is considered a key control point in gene expression. Which of the following statements explains why?
Question 3
HLPaper 1B
In the image below, the left panel shows changes in global DNA methylation levels (%) in somatic cells over three generations (F0 to F3) following an environmental stimulus in the F0 generation. The right panel displays the expression level of a phenotypic trait over six generations (F0 to F5), highlighting how the phenotype changes across generations despite no changes in the DNA sequence.
1.[1]
State the trend in DNA methylation observed from F0 to F3.
2.[2]
Based on the right graph, identify the generation in which the phenotypic trait expression peaks. Suggest a possible epigenetic explanation for this change.
3.[2]
Explain how DNA methylation can be involved in the heritable silencing of gene expression.
4.[3]
Describe how epigenetic changes, such as those shown here, can contribute to phenotypic plasticity without altering the DNA sequence.
Question 4
HLPaper 1A
The number of protein-coding genes in the human genome is estimated to be about 20000 , which is much less than the size of the proteome. What is one reason for this?
Question 5
HLPaper 2
1.[4]
Define epigenesis and epigenome, and briefly describe their significance in multicellular organisms.
2.[3]
Describe how methylation of the promoter region in DNA impacts gene expression.
3.[3]
Outline one example of environmental effects on gene expression, including the mechanism by which this occurs.
Question 6
HLPaper 2
1.[3]
Define genotype, phenotype, and gene expression.
2.[1]
List two stages in the process of gene expression.
Question 7
HLPaper 1B
1.[4]
Explain the regulation of transcription by transcription factors that bind to the promoter sequence of DNA.
Question 8
HLPaper 1A
The function of silencer DNA sequences is to:
Question 9
HLPaper 1A
Which process involves the removal of introns?
Question 10
HLPaper 2
1.[5]
Outline the consequences of epigenetic imprinting in lion-tiger hybrids, explaining the origin of size differences between ligers and tigons.
2.[5]
Describe how environmental pollutants, such as air pollution, can influence the epigenetic regulation of immune response genes.
3.[5]
Outline the mechanism by which oestrogen regulates gene expression related to endometrial development and maintenance in the uterine cycle.