Home › IB Biology › Practice › Mut. & Gene Edit.IB Diploma · Biology D1.3
IB Biology D1.3: Mut. & Gene Edit. — Practice Questions & Answers
IB Biology D1.3 study notes: gene and chromosome mutations, mutagens, the sickle-cell example, somatic versus germline mutations, and CRISPR gene editing.
Here are 10 practice questions with full answers and explanations.
Start an interactive IB Biology quiz →
Practice questions with answers
1
Multiple choice
What is a mutation?
A change in protein structure
A change in the DNA sequence
A change in lipid composition
A change in the RNA sequence
Tap an answer to check it.
Why A mutation is a change in the nucleotide sequence of an organism's DNA.
2
Multiple choice
What is a point mutation?
A change in multiple base pairs
A change in an entire gene
A change in a single base pair
A change in a chromosome
Tap an answer to check it.
Why A point mutation is a change affecting a single base pair in the DNA.
3
Multiple choice
What is a frameshift mutation?
A substitution of base pairs
An insertion or deletion of base pairs
An inversion of chromosomes
A duplication of genes
Tap an answer to check it.
Why A frameshift mutation results from inserting or deleting bases in a number not divisible by three, shifting the reading frame.
4
Multiple choice
What is a silent mutation?
A mutation that introduces a stop codon
A mutation that does not change the amino acid sequence
A mutation that changes the protein structure
A mutation that changes the amino acid sequence
Tap an answer to check it.
Why A silent mutation alters a codon but, due to degeneracy of the genetic code, still specifies the same amino acid.
5
Multiple choice
What is a missense mutation?
A mutation that introduces a stop codon
A mutation that changes the amino acid sequence
A mutation that changes the protein structure
A mutation that does not change the amino acid sequence
Tap an answer to check it.
Why A missense mutation changes a codon so that a different amino acid is inserted, potentially altering protein function.
6
Multiple choice
What is a nonsense mutation?
A mutation that does not change the amino acid sequence
A mutation that introduces a stop codon
A mutation that changes the protein structure
A mutation that changes the amino acid sequence
Tap an answer to check it.
Why A nonsense mutation converts a codon into a premature stop codon, truncating the polypeptide during translation.
7
Multiple choice
What is a mutation?
A change in the DNA sequence
A change in lipid composition
A change in the RNA sequence
A change in protein structure
Tap an answer to check it.
Why A mutation is any change in the base sequence of an organism's DNA.
8
Multiple choice
What is a point mutation?
A change in multiple base pairs
A change in a single base pair
A change in an entire gene
A change in a chromosome
Tap an answer to check it.
Why A point mutation is a change affecting a single base pair, such as a substitution.
9
Multiple choice
What is a frameshift mutation?
A substitution of base pairs
A duplication of genes
An insertion or deletion of base pairs
An inversion of chromosomes
Tap an answer to check it.
Why A frameshift mutation is caused by insertions or deletions that shift the codon reading frame.
10
Multiple choice
What is a silent mutation?
A mutation that changes the protein structure
A mutation that changes the amino acid sequence
A mutation that introduces a stop codon
A mutation that does not change the amino acid sequence
Tap an answer to check it.
Why A silent mutation changes a codon but still codes for the same amino acid, leaving the protein unchanged.
Key terms in Mut. & Gene Edit.
Mutation: A random change in the base sequence of DNA; the ultimate source of new alleles and genetic variation.
Base substitution: A point mutation in which one base in a gene is replaced by a different base.
Mutagen: An environmental factor, such as ionising radiation or certain chemicals, that increases the rate of mutation.
Carcinogen: An agent that can cause cancer, often by causing mutations in body cells.
Silent mutation: A base substitution that, owing to the degenerate code, does not change the amino acid coded for and so has no effect on the protein.
Somatic mutation: A mutation in a body cell; not inherited by offspring but passed to that cell’s descendants.
Germline mutation: A mutation in a cell that forms gametes; it can be inherited by offspring.
Sickle-cell anaemia: A genetic disease caused by a single base substitution replacing glutamic acid with valine in beta-globin.
See the full study notes for this topic.
Practise other IB Biology topics