Biology

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.

Safflower, Carthamus tinctorius, is a minor crop grown in Australia for the edible and industrial oil markets. Commercial safflower production occurs mainly in New South Wales, Victoria and South Australia. After oil is extracted from the seed, the remaining meal can be used as stockfeed. The first commercial GM (genetically modified) safflower was released in Australia in 2018. There are both supporters and critics for the use of this biotechnology.
Discuss ONE social or cultural issue which has influenced the use of a named GM crop.

Safflower, Carthamus tinctorius, is a minor crop grown in Australia for the edible and industrial oil markets. Commercial safflower production occurs mainly in New South Wales, Victoria and South Australia. After oil is extracted from the seed, the remaining meal can be used as stockfeed. The first commercial GM (genetically modified) safflower was released in Australia in 2018. There are both supporters and critics for the use of this biotechnology.
Describe the benefits of ONE other named transgenic crop to agriculture.

The Amur leopard, Pantherea pardus orientalis are a subspecies of leopard only found in Russia and China. The Amur leopard has been listed as Critically Endangered with an estimated population of 100 individuals recorded in 2017. Breeding programs are used in zoological parks to help avoid extinction.
The gel electrophoresis shown below considers several DNA markers for a female Amur leopard and three potential mates from other zoos.
Justify the use of gel electrophoresis in selecting the pair of Amur leopards, from this captive population, that you would recommend for breeding. Support your answer with reference to the data.

Ovulation in women is associated with a rapid increase in luteinising hormone (LH). Test strips can be used to detect high levels of LH in urine. Once a test strip is used, a control line should appear and the presence of a test line indicates high levels of LH in urine. The image below represents four different results that were obtained.
Which of the results indicates a valid test which shows that ovulation is NOT occurring?
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.

Giardiasis is the most common form of non-bacterial diarrhoea of people in Australia. The adult parasite, Giardia lamblia, responsible for the disease, is shown in the figure below. The adult is a single cell. Its ventral side is flattened and has a shallow depression used as a type of sucker. Giardia lives in the upper part of the intestine (duodenum) of an infected person where it rapidly multiplies. To pass from one human to another it encloses itself in a cyst that passes out in the faeces.
Describe ONE procedure that would be suitable for preventing the spread of Giardia and justify its use.

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.

Some types of leukocytes can change this shape to engulf foreign particles, for example bacteria. This process also includes the foreign particle being destroyed inside the cell.
Name the process described above.

A patient visited an audiologist for a hearing test. The audiologist tested both ears at specific frequencies. The volumes at which each frequency could be heard are shown. It is discovered that there is a complete and permanent blockage of the outer ear, but the cochlea is still fully functional. Justify the use of a suitable technology to assist the patient’s hearing.

Some types of leukocytes can change this shape to engulf foreign particles, for example bacteria. This process also includes the foreign particle being destroyed inside the cell.
The process above is a non-specific response to an antigen. Outline ONE physical change that occurs in a host’s cell or tissue in response to a pathogen by the human immune system.

The graph below shows the change in antibody concentration over time after vaccination involving an initial and then second, or booster, dose.
Identify the time at which the primary and secondary vaccinations were given and account for the features of the graph using your knowledge of primary and secondary immune response. Annotate the graph to support your answer.

Sexual reproduction is a mechanism that has evolved to ensure the continuity of species. In animals several reproductive strategies ensure that reproduction occurs effectively in the environment they live in. Both internal and external fertilisation strategies are known to produce reproductive success.
“Internal fertilisation is more advantageous than external fertilisation in ensuring the continuity of a species”.
Assess the above statement.

Lead poisoning is a serious health problem. Too much lead can affect all organs, including the kidneys, causing “lead related nephrotoxicity”. In extreme cases nephrotoxicity causes polycystic kidney disease in which fluid-filled cysts grow in the kidney, interfering with the normal kidney tissue and limiting the kidney’s ability to filter the blood. The number of cysts builds up over time, enlarging the kidney and ultimately causing renal failure.
Evaluate the effectiveness of an identified technology that can assist with this type of disorder. In your answer include any specific limitations of the treatment or consequences for the patient’s diet and/or lifestyle associated with the use of this technology.

The coiled-coil was one of the earliest tertiary protein structures described and first discovered in the two-stranded coiled-coil protein (CC) alpha-keratin. Coiled-coils consist of two or more alpha-helices winding around each other.
Figure 1: Coiled-coil
Such proteins are involved in a wide variety of structural and mechanical processes in cells. Long-CC (LCC) includes long coiled-coils with a minimum stretch of 70 amino acids in one coiled coil and a minimum stretch of 50 amino acids in the other.
A study was carried out to compare the presence of CC and LCC proteins in species from different kingdoms. The graph below represents the estimated percentages of CC proteins, LCC proteins and superlong CC per genome for 22 different species.
Figure 2: % coiled-coil proteins per genome for 22 species. A: Archaea; B: Gram positive bacteria; C: Gram negative bacteria; D: Fungi; E: Animals; F: Plants

“Animals are more closely related to plants than other kingdoms”. Analyse the data provided and assess whether this statement is supported.

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.

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.

Foetal alcohol spectrum disorders (FASDs) are one of the growing class of lifestyle caused disorders. FASDs are a group of conditions that can occur in a person whose mother drank alcohol during pregnancy. People with FAS have central nervous system (CNS) problems, minor facial feature abnormalities, and growth problems. People with FAS can have problems with learning, memory, attention span, communication, vision, or hearing. They might have a mix of these problems. People with FAS often have a hard time in school and trouble getting along with others.
The poster shown is an example of a poster from an educational program that targets FASD.

Explain the use of this educational program to society.

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. Figure 1: Crown gall The interaction between a plant and Agrobacterium is detailed below: (A) Agrobacteria cells produce the hormones cytokinin and auxin, which increase host susceptibility and inhibit H2O2 production and hypersensitive response (HR) upon infection. (B) After integration of the bacterial T-DNA into the plant genome, cytokinin and auxin are synthesized by T-DNA encoded enzymes and accumulate inside the tumour. (C) This causes massive changes in the gene expression pattern resulting in metabolomic and morphological adaptations that are necessary for tumour growth and differentiation. (D) Loss of water is minimized by an increase in the levels of the stress hormone ABA. Evaporation of water from the disrupted crown gall surface drives the flow of water and minerals into crown galls. (E) Because photosynthesis is downregulated, the O2 levels are low, the tumour produces C and N compounds heterotrophically and gains energy mainly anaerobically by alcoholic fermentation. (F) The developing tumour becomes a metabolic sink for the host plant, which accumulates metabolites produced by source leaves and minerals taken up by the roots. (G) Auxin and cytokinin also cause an increase in ethylene (ET) which together with salicylic acid (SA) inhibits agrobacterial virulence. (H) ABA induces DNA methylation of the plant genome, regulating gene expression of drought- stress responsive genes. The oncogenes of the T-DNA remain unaffected by methylation of the plant genome.

Identify a mechanism by which the plant maintains homeostasis when infected by agrobacterium.

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. Figure 1: Crown gall The interaction between a plant and Agrobacterium is detailed below: (A) Agrobacteria cells produce the hormones cytokinin and auxin, which increase host susceptibility and inhibit H2O2 production and hypersensitive response (HR) upon infection. (B) After integration of the bacterial T-DNA into the plant genome, cytokinin and auxin are synthesized by T-DNA encoded enzymes and accumulate inside the tumour. (C) This causes massive changes in the gene expression pattern resulting in metabolomic and morphological adaptations that are necessary for tumour growth and differentiation. (D) Loss of water is minimized by an increase in the levels of the stress hormone ABA. Evaporation of water from the disrupted crown gall surface drives the flow of water and minerals into crown galls. (E) Because photosynthesis is downregulated, the O2 levels are low, the tumour produces C and N compounds heterotrophically and gains energy mainly anaerobically by alcoholic fermentation. (F) The developing tumour becomes a metabolic sink for the host plant, which accumulates metabolites produced by source leaves and minerals taken up by the roots. (G) Auxin and cytokinin also cause an increase in ethylene (ET) which together with salicylic acid (SA) inhibits agrobacterial virulence. (H) ABA induces DNA methylation of the plant genome, regulating gene expression of drought- stress responsive genes. The oncogenes of the T-DNA remain unaffected by methylation of the plant genome.

“Regulation of genes affects the phenotype of the organism.” Discuss this statement using 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.