Biology

Human papillomavirus (HPV) is a group of viruses that infect the skin and mucous membranes of humans. HPV viruses are classified into different serotypes based on the DNA sequences of their viral genomes. Each HPV type is identified by a specific number (e.g., HPV-16, HPV-18, etc.). HPV types can cause changes in the cells of the cervix, leading to the development of precancerous lesions. If these lesions are left untreated, they may progress to invasive cervical cancer. HPV binds to the surface of epithelial cells and gain entry via endocytosis. Once inside the cell it introduces its viral DNA into the cells nucleus. It uses the hosts cell’s machinery to produce a viral E6 protein. Schematic of HPV infection of a epithelial cell Adapted from Human Papillomavirus and Oropharynx Cancer: Biology, Detection and Clinical Implications

The graph below shows the ten year cumulative incidence rate of cervical precancer by different HPV serotypes. Patiens were tested for HPV at the beginning of the 10 year period.

Analyse the trends shown in the data.

Human papillomavirus (HPV) is a group of viruses that infect the skin and mucous membranes of humans. HPV viruses are classified into different serotypes based on the DNA sequences of their viral genomes. Each HPV type is identified by a specific number (e.g., HPV-16, HPV-18, etc.). HPV types can cause changes in the cells of the cervix, leading to the development of precancerous lesions. If these lesions are left untreated, they may progress to invasive cervical cancer. HPV binds to the surface of epithelial cells and gain entry via endocytosis. Once inside the cell it introduces its viral DNA into the cells nucleus. It uses the hosts cell’s machinery to produce a viral E6 protein. Schematic of HPV infection of a epithelial cell Adapted from Human Papillomavirus and Oropharynx Cancer: Biology, Detection and Clinical Implications Question 33 (continued) Marks 4

A vaccine has been developed to protect against infection with HPV. Describe how giving this vaccine leads to the production of antibodies against HPV.

The graph below shows the cumulative Incidence of Invasive Cervical Cancer According to HPV Vaccination Status

A healthy person in a hot environment measures their body temperature to be 38.0°C. Which of the following might occur in this person?
A. Shivering
B. Vasodilation
C. Goosebumps
D. Pale appearance

Some desert mammals can obtain their water from breaking down stored body fat. What type of adaptation is this?
A. Behavioural
B. Environmental
C. Physiological
D. Structural

What type of protein is formed in response to a pathogen?
A. Antibody
B. Antigen
C. Antihistamine
D. Antiseptic

A diagram of the human female reproductive system is shown.
Where does implantation normally occur?
A. W
B. X
C. Y
D. Z

Animal cloning involves inserting the nucleus from a somatic cell of one animal into the
A. plasmid of a bacterium.
B. uterus of a surrogate animal.
C. fertilised egg from another animal.
D. enucleated egg from another animal.

In mice, muscle cells contain 40 chromosomes. Which of the following is a correct statement about mouse cells?
A. The gametes contain 20 pairs of chromosomes.
B. The somatic cells contain 20 pairs of chromosomes.
C. The cells produced by meiosis contain 40 chromosomes.
D. The cells produced by mitosis contain 40 pairs of chromosomes.

A new vaccine against an infectious disease was developed. The effectiveness of the vaccine in preventing infection in humans was plotted over time in three different age groups.

Which of the following is a valid conclusion that can be drawn from the data in the graph?
A. The vaccine is ineffective after six months.
B. The younger the person the more effective the vaccine.
C. The younger the person, the faster the immunity to infection declines.
D. The vaccine offers more protection to younger people than those over 65.

The following diagram represents a short section of DNA.
What are the components labelled X, Y and Z ?

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.

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.

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.

A student constructed a model of the phases of meiosis in an organism with six chromosomes in its somatic cells. One of the early phases is shown.
Which of the following identifies an error in the model?
A. Chromosomes are not lined up single file on the metaphase plate.
B. Chromosomes of matching size and structure are not paired.
C. There are no homologous chromosomes.
D. There are too many chromosomes.

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

A person with short-sighted vision (myopia) was incorrectly given a pair of spectacles with convex lenses.
Which row of the table demonstrates what happens?

Renal dialysis involves passing blood from a patient past a dialysate solution in order to remove waste such as urea from the blood.
Which diagram correctly shows possible concentrations of urea and the direction of flow of both solutions in a dialysis machine?

Outline ONE way that a pathogen can pass from person to person.

The following key can be used to classify some pathogens.
Complete each empty box with an appropriate pathogen.

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.