Biology

Female Jack Jumper ants (Myrmecia pilosula) have a single pair of chromosomes. During meiosis, crossing over occurs. The diagram shows the crossing over and the position of three genes on the chromosomes.

Draw the chromosomes of the four possible gametes after crossing over for the Jack Jumper ants occurs. Include the alleles for each gene.

Female Jack Jumper ants (Myrmecia pilosula) have a single pair of chromosomes. During meiosis, crossing over occurs. The diagram shows the crossing over and the position of three genes on the chromosomes.

Outline the significance of crossing over for the Jack Jumper ants.

In the human ABO blood group system, the alleles for antigens A and B are both expressed in an individual carrying both alleles. This is an example of:
(A) incomplete dominance
(B) co-dominance
(C) hybrid vigour
(D) polygenic expression

The diagram below shows a pedigree of a family carrying the sex-linked allele for red-green colour blindness.

From which member of his family did E inherit the allele for colour-blindness?
(A) A
(B) B
(C) C
(D) D

An inherited characteristic in a family is mapped in the pedigree shown.
Inheritance of this characteristic is
A. autosomal recessive.
B. sex-linked recessive.
C. autosomal dominant.
D. sex-linked dominant.

In a plant species, red flower colour (R) is dominant over white flower colour (r). Two plants of known genotype for flower colour were crossed. A punnet square was used to determine the proportion of genotypes expected in the offspring. Part of the punnet square is shown.
Which statement is true for the parents in this cross?
A. Both parents were homozygous.
B. Both parents were heterozygous.
C. Both parents had flowers of the same colour.
D. Parent 2 must have red flowers and Parent 1 must have white flowers.

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

Eggplant fruit comes in three colours: dark purple, white and violet. A genetic cross between the dark purple and white eggplants will always result in the violet phenotype. What phenotypic ratio would you expect to see when two violet offspring are crossed? Show your working.

Offspring are rarely identical to their parents.
Compare the ways in which genetic variation can arise from asexual and sexual reproduction.

Cystic fibrosis is an autosomal recessive disorder caused by mutations in the CFTR gene. Many different recessive alleles cause cystic fibrosis. The four most common alleles of the CFTR gene and their frequencies in the Australian population are shown in the table. What will be the most common genotype of cystic fibrosis patients in Australia?
A. a1/a1
B. a1/a2
C. A/a1
D. A/A

Which of the following is correct about the genotype of the identified individual?
A. I–1 is type 1.
B. II–2 is type 2.
C. III–2 is type 3.
D. III–12 is type 4.

In a population of rabbits, black fur colour is dominant over white fur. A black rabbit, whose mother has white fur, mates with a white rabbit. Predict the phenotypic ratio for the offspring of this cross. Show your working.

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.

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.

In rabbits, an unlinked second gene controls the length of fur, if any. Long hair (L) is dominant over short hair (l). A long-haired rabbit was crossed with a furless rabbit to produce many offspring, all of which have fur. One-quarter of the offspring are short-haired rabbits. Deduce the genotypes of the two parent rabbits. Show working.

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.

Graph the frequencies of B and b as a function of generation.

A normal allele results in liver cells with sufficient cholesterol receptors. A different allele results in liver cells without cholesterol receptors. Individuals who are heterozygous have liver cells with insufficient cholesterol receptors. What type of inheritance is the most likely explanation for this?
A. Sex-linked
B. Autosomal dominant
C. Autosomal recessive
D. Incomplete dominance

There are about 10 million single nucleotide polymorphisms (SNPs) found in the human genome. Four SNPs are modelled in the diagram.
The SNPs modelled do not affect the phenotype of the individuals shown. Which is the best explanation for this?
A. Only one nucleotide is different at each SNP.
B. The SNPs are part of DNA that is not expressed.
C. AGA, CAA, TAT and CTC all code for the same amino acid.
D. The SNPs are present on one strand of the DNA molecule only.

One of the genes involved in determining the colour of a species of fish has two alleles: yellow and orange. The diagram shows a pedigree chart for the inheritance of colour in the fish.
Use the pedigree chart to explain why the yellow allele is recessive.

Explain how a cross between individuals I and II could be used to determine whether the inheritance of colour in the fish is sex-linked or autosomal.

Explain the effect of meiosis on genetic variation.

A group of four students set out to determine the animal species diversity over an area of one hectare in each of five different habitats. Each student graphed their data as shown.
Which of the graphs produced is the most suitable to represent animal species diversity in the different habitats?

Which of the following is always true of a mutation that produces a dominant allele?
A. It will be lethal in a population.
B. It will be expressed in heterozygous individuals.
C. It will only be expressed in homozygous individuals.
D. It will spread more quickly through the population than a recessive allele.

The pedigree shows the inheritance of a genetic disorder.
Which row of the table correctly identifies the two possible types of inheritance for this disorder?

A human karyotype that shows evidence of chromosomal mutation is shown.

Explain how cell division and fertilisation could lead to the production of this karyotype.