Biology

Outline how ONE type of electromagnetic radiation can cause a germline mutation.
Name of electromagnetic radiation: .................................

Cystic fibrosis is an inherited disorder that causes damage to the lungs, digestive system and other organs in the body. A person with cystic fibrosis will have two faulty recessive alleles for the cystic fibrosis gene (CFTR) on chromosome 7.
Explain how the deletion of nucleotides in the CFTR gene removes only one amino acid. Include reference to the nucleotides that code for isoleucine and phenylalanine amino acids.

The diagram below shows a point mutation occurring on a strand of DNA.
What is the most likely possible outcome of this point mutation on the phenotype of the individual?
(A) Change to phenotype as the mutation occurs on non-coding DNA.
(B) No change to phenotype as the mutation occurs on non-coding DNA.
(C) Change to phenotype as all mutations affect the phenotype, regardless of where they occur.
(D) No change to phenotype as point mutations do not affect the phenotype of the individual.

The section of DNA shown in Question 12 came into contact with a mutagen, resulting in a change in the cytosine. The effect on the DNA after several replication cycles is shown.
The mutagen has resulted in
A. a frame-shift mutation.
B. an increase in cytosine.
C. a change in one base pair.
D. a change in one nucleotide.

What is the significance of mutations in non-coding DNA?
A. They do not alter nucleotides.
B. They do not affect phenotype.
C. They may affect gene expression.
D. They may alter amino acid codons.

The occurrence of a genetic disease in a family resulting from the presence of a dominant allele is shown. 1 2 KEY Affected male Unaffected male 3 4 5 Affected female Unaffected female If the disease has arisen as a result of a mutation, which of the following is the most likely cause of the disease in this family?
A. A germ-line mutation in individual 2
B. A germ-line mutation in individual 4
C. A somatic mutation in individuals 1 and 2
D. A somatic mutation in individuals 4 and 5

Birth defects in humans can be caused by chromosomal abnormalities.

Explain the cause of a type of chromosomal mutation.

Mutations occurring in cells which do not go on to form gametes can be classified as:
A. somatic mutations
B. germ line mutations
C. morphological mutations
D. oncogenes

A mutation involving a DNA deletion is illustrated. Which statement about the mutation is correct? A. It will have an effect on many genes. B. It will have an effect on only one codon. C. It may be the result of an error during translation. D. It may be the result of an error during transcription.

Over millions of years of evolution, mutations occur at a broadly constant rate within a gene. This allows genes to be used as molecular clocks. The diagram below shows how the base sequence in part of a gene changed as two evolutionary lineages diverged from an original base sequence. Assuming this rate of mutation continued, by how many bases would this part of the gene differ in Species X compared with Species Y 20 million years after diverging from the original base sequence?
A. 4
B. 8
C. 16
D. 20

Many transgenic crops have been genetically engineered to have traits such as herbicide resistance. In at least four different crops the transgene has been found in nearby wild plant relatives of the cultivated crops. What is the most likely reason for this observation?
A. Crossing over in the wild plants
B. Gene flow from the crops to the wild plants
C. Genetic drift from the crops to the wild plants
D. Mutations in the wild plants that match the transgenes

An example of the mutagenic effect of ultraviolet radiation (UV) on DNA is shown in the diagram. What is the mutagenic effect that is modelled?
A. Thymine is duplicated.
B. Bonds are formed between adjacent bases.
C. Nucleotides form bonds in the backbone of DNA.
D. Thymines on the two strands of DNA form bonds.

The following events occur after DNA is subjected to radiation. The events are listed in no specific order. W: Mutation X: Change in cell activity Y: Change in protein structure Z: Change in polypeptide sequence What is the correct sequence of steps?
A. W, X, Y, Z
B. Z, X, W, Y
C. Z, Y, X, W
D. W, Z, Y, X

In a separate experiment, cells are treated with a chemical mutagen that causes only nucleotide substitutions in DNA. Which of the following is the most correct prediction for the result of a comet assay for this treatment?
A. The tail will be longer than a cell with double-stranded breaks in DNA.
B. The head will remain in place and the tail will move towards the negative terminal.
C. The only visible part will be the head with no tail.
D. There will be no visible head or tail.

An incidence of an autosomal dominant trait is shown in the pedigree.
Is this trait likely to be the result of a somatic or a germ-line mutation? Justify your answer.

An incidence of an autosomal dominant trait is shown in the pedigree. KEY Unaffected female Unaffected male Male with trait The diagram shows the early stages of embryonic development from a fertilised egg. The developing ball of cells has split and monozygotic (identical) twins have formed. Mutations can occur at different times during embryonic development, for example Mutation A would result in both twins having the mutation in all their cells.
Explain the effects of Mutation B and Mutation C on each twin and on any offspring that they may have.

The data below examines the changes in allele frequencies at a single locus with two alleles B and b in two very large populations of rabbits due to natural selection. It is known that a variety of genetic traits affect the survivability of rabbits in the wild, as well as in breeding populations. One such trait is furless rabbits (naked bunnies). This trait was first discovered in England by W.E. Castle in 1933. The furless rabbit is rarely found in the wild because the cold English winters are a selective pressure against it. The dominant allele for normal fur is represented by B and the recessive allele for no fur is represented by b.

Account for the shape of the graph. Support your answer with reference to the information provided.

Agrobacterium tumefaciens is a rod-shaped bacterium found in soil. Its flagella allow it to move through the soil in response to chemicals released by wounded plant cells. Once it enters its plant host, it injects a section of its DNA called the T-DNA which is derived from its Ti (tumour inducing) plasmid into its host causing the host to form undifferentiated (tumour) tissue termed a crown gall.

Explain how agrobacterium can operate as a mutagen.

A farmer intends to artificially inseminate cows with semen from a bull which has been chosen based on characteristics of colour and muscle mass. The farmer does not know that the bull is heterozygous for a rare recessive allele not previously present in the farmer’s cow population. The introduction of this recessive allele to the population of cows is an example of
A. gene flow.
B. genetic drift.
C. natural selection.
D. selective breeding.

The following diagram shows a mutation.
Outline another type of mutation.

The following diagram shows a mutation. Original
What type of mutation is shown in the diagram?

Explain how TWO processes that affect the gene pool of populations can lead to evolution.

The diagram shows the impact of birds feeding on a population of beetles over time.

Which of the following accounts for the change in the beetle population?
A. Mutation
B. Gene flow
C. Genetic drift
D. Environmental pressure