Mock Exam 2
VCE Biology Units 3 & 4 | Immunity, Disease and Pathogens
✎ 120 marks total • approximately 150 minutes. Complete ALL questions on paper before opening the Model Answers lesson. Reading time: 15 minutes (recommended). No notes.
SECTION A — MULTIPLE CHOICE (40 marks)
Question 1 (1 mark)
Which of the following is an example of innate (non-specific) immunity?
✎ Circle your answer
A) Production of antibodies
B) T cell activation
C) Inflammation response
D) Memory B cells
Question 2 (1 mark)
Antibodies are produced by:
✎ Circle your answer
A) T helper cells
B) Cytotoxic T cells
C) Plasma cells (differentiated B cells)
D) Macrophages
Question 3 (1 mark)
The primary immune response differs from the secondary immune response in that:
✎ Circle your answer
A) Only primary involves antibodies
B) Secondary is faster and produces higher antibody levels due to memory cells
C) Primary involves T cells; secondary involves B cells
D) Secondary only occurs for bacterial infections
Question 4 (1 mark)
Which type of immunity is conferred by vaccination?
✎ Circle your answer
A) Passive natural immunity
B) Passive artificial immunity
C) Active artificial immunity
D) Active natural immunity
Question 5 (1 mark)
MHC class I molecules present antigens to:
✎ Circle your answer
A) B cells
B) Cytotoxic T cells (CD8+)
C) Helper T cells (CD4+)
D) Natural killer cells
Question 6 (1 mark)
Which cells are responsible for cell-mediated immunity?
✎ Circle your answer
A) B cells and plasma cells
B) T lymphocytes
C) Mast cells
D) Erythrocytes
Question 7 (1 mark)
An antigen is defined as:
✎ Circle your answer
A) A molecule produced by the immune system
B) A molecule that triggers an immune response
C) A type of white blood cell
D) A protein that neutralises pathogens
Question 8 (1 mark)
Which of the following is NOT a physical barrier of innate immunity?
✎ Circle your answer
A) Skin
B) Mucus membranes
C) Cilia in respiratory tract
D) Lymph nodes
Question 9 (1 mark)
Autoimmune diseases occur when:
✎ Circle your answer
A) The immune system fails to respond to pathogens
B) The immune system attacks the body’s own tissues
C) Too many antibodies are produced
D) The body is infected by a new pathogen
Question 10 (1 mark)
Passive immunity differs from active immunity in that:
✎ Circle your answer
A) It involves memory cells
B) Protection is immediate but short-lived; no memory cells formed
C) Vaccines provide passive immunity
D) It takes weeks to develop
Question 11 (1 mark)
The variable region of an antibody determines:
✎ Circle your answer
A) Its class (IgG, IgM, etc.)
B) Its antigen-binding specificity
C) Whether it activates complement
D) Its ability to cross the placenta
Question 12 (1 mark)
Clonal selection theory explains how:
✎ Circle your answer
A) All B cells produce the same antibody
B) B cells with receptors matching an antigen are selected and proliferate
C) T cells destroy all antigens
D) Memory cells are deleted after infection
Question 13 (1 mark)
Which of the following describes a prion?
✎ Circle your answer
A) A virus with RNA genome
B) A misfolded protein that causes normal proteins to misfold
C) A bacterium without a cell wall
D) A parasite with complex life cycle
Question 14 (1 mark)
Herd immunity is achieved when:
✎ Circle your answer
A) Every individual is vaccinated
B) A sufficient proportion of a population is immune to prevent spread
C) All pathogens are eliminated
D) The immune response becomes stronger over time
Question 15 (1 mark)
HIV targets cells expressing CD4 receptor, primarily:
✎ Circle your answer
A) Cytotoxic T cells
B) B cells
C) T helper cells (CD4+)
D) Natural killer cells
Question 16 (1 mark)
The complement system is part of:
✎ Circle your answer
A) Adaptive immunity only
B) Both innate and adaptive immunity
C) Only cell-mediated immunity
D) Only passive immunity
Question 17 (1 mark)
Which class of antibody is found in breast milk and provides passive immunity to newborns?
✎ Circle your answer
A) IgM
B) IgG
C) IgA
D) IgE
Question 18 (1 mark)
In allergic reactions, IgE antibodies bind to:
✎ Circle your answer
A) B cells
B) Cytotoxic T cells
C) Mast cells → degranulation releases histamine
D) Complement proteins
Question 19 (1 mark)
Which best describes the role of dendritic cells?
✎ Circle your answer
A) Produce antibodies
B) Kill virus-infected cells directly
C) Present antigens to T cells (antigen-presenting cells)
D) Secrete complement proteins
Question 20 (1 mark)
The purpose of the thymus is to:
✎ Circle your answer
A) Produce B cells
B) Mature and select T cells (positive and negative selection)
C) Filter blood for pathogens
D) Produce antibodies
Question 21 (1 mark)
Which feature is characteristic of bacterial pathogens but absent in viruses?
✎ Circle your answer
A) A nucleic acid genome
B) A cell wall containing peptidoglycan and independent metabolic machinery for replication
C) The ability to cause disease
D) A protein coat
Question 22 (1 mark)
Fungal pathogens such as Candida albicans differ from bacterial pathogens in that fungi:
✎ Circle your answer
A) Are prokaryotic
B) Are eukaryotic, with a cell wall made of chitin rather than peptidoglycan
C) Lack a cell wall entirely
D) Can only reproduce inside a host cell
Question 23 (1 mark)
Plasmodium, the protozoan parasite that causes malaria, is transmitted to humans via:
✎ Circle your answer
A) Direct person-to-person contact
B) Contaminated water
C) The bite of an infected Anopheles mosquito (a vector)
D) Airborne droplets
Question 24 (1 mark)
Which statement correctly describes viruses?
✎ Circle your answer
A) They can independently carry out protein synthesis using their own ribosomes
B) They are obligate intracellular parasites that must use a host cell’s machinery (e.g. ribosomes) to replicate
C) They reproduce by binary fission outside a host cell
D) They possess peptidoglycan cell walls
Question 25 (1 mark)
Which of the following best distinguishes neutrophils from macrophages in innate immunity?
✎ Circle your answer
A) Neutrophils are the most abundant phagocyte and are typically first to arrive at a site of infection but are short-lived, whereas macrophages arrive later and are longer-lived
B) Macrophages cannot phagocytose pathogens
C) Neutrophils present antigens to T cells while macrophages do not phagocytose
D) Only macrophages are part of the innate immune system
Question 26 (1 mark)
Natural killer (NK) cells recognise and destroy infected or abnormal cells primarily by detecting:
✎ Circle your answer
A) Antigens presented on MHC class II
B) A reduced or absent level of MHC class I on the target cell’s surface (‘missing self’)
C) The presence of antibodies bound to the cell
D) High levels of MHC class I expression
Question 27 (1 mark)
Interferons released by virus-infected cells act to:
✎ Circle your answer
A) Directly destroy the virus inside the infected cell
B) Signal neighbouring, uninfected cells to increase antiviral defences (e.g. degrade mRNA, inhibit protein synthesis), limiting the spread of the virus
C) Produce antibodies against the virus
D) Present antigen to helper T cells
Question 28 (1 mark)
The classical pathway of complement activation is triggered by:
✎ Circle your answer
A) Direct binding of complement proteins to microbial surfaces without antibody
B) Antibody bound to antigen on a pathogen’s surface
C) Mannose-binding lectin binding to pathogen sugars
D) T cell receptor binding to MHC
Question 29 (1 mark)
The membrane attack complex (MAC), formed by complement proteins, kills targeted pathogens by:
✎ Circle your answer
A) Coating the pathogen to enhance phagocytosis
B) Forming pores in the pathogen’s membrane, causing lysis
C) Neutralising toxins
D) Presenting antigen to T cells
Question 30 (1 mark)
‘Opsonisation’ refers to the process by which:
✎ Circle your answer
A) Antibodies or complement proteins coat a pathogen, enhancing its recognition and engulfment by phagocytes
B) Pathogens are destroyed directly by antibodies
C) Interferons are released from infected cells
D) T cells are selected in the thymus
Question 31 (1 mark)
Which class of antibody is produced first in a primary immune response and is typically found as a pentamer?
✎ Circle your answer
A) IgG
B) IgA
C) IgM
D) IgE
Question 32 (1 mark)
Class switching, in which a B cell changes the antibody class it produces (e.g. from IgM to IgG) while keeping the same antigen specificity, is stimulated by:
✎ Circle your answer
A) Cytokines released from activated helper T cells
B) Direct contact with the pathogen only
C) Complement proteins alone
D) Interferons only
Question 33 (1 mark)
V(D)J recombination is a process that occurs during lymphocyte development and is responsible for:
✎ Circle your answer
A) Randomly rearranging gene segments to generate the enormous diversity of B cell and T cell receptor specificities
B) Removing self-reactive lymphocytes
C) Producing memory cells
D) Activating the complement cascade
Question 34 (1 mark)
Negative selection of T cells in the thymus functions to:
✎ Circle your answer
A) Select T cells that respond most strongly to self-antigens for survival
B) Eliminate (via apoptosis) T cells whose receptors bind too strongly to self-antigens, helping prevent autoimmunity
C) Convert helper T cells into cytotoxic T cells
D) Produce antibodies against self-antigens
Question 35 (1 mark)
In Type 1 diabetes, the primary target of the autoimmune attack is:
✎ Circle your answer
A) The myelin sheath of neurons
B) The synovium of joints
C) Insulin-producing beta cells of the pancreas
D) Red blood cells
Question 36 (1 mark)
Multiple sclerosis is an autoimmune disease in which the immune system attacks:
✎ Circle your answer
A) The myelin sheath surrounding nerve fibres in the central nervous system
B) Pancreatic beta cells
C) The thyroid gland
D) Skin cells
Question 37 (1 mark)
Rheumatoid arthritis is an autoimmune condition primarily characterised by immune attack on:
✎ Circle your answer
A) The synovial membrane lining the joints, causing chronic inflammation and joint damage
B) Pancreatic islet cells
C) The myelin sheath
D) The thymus
Question 38 (1 mark)
Type I (immediate) hypersensitivity reactions, such as anaphylaxis, are mediated mainly by:
✎ Circle your answer
A) IgG antibodies and complement
B) IgE antibodies bound to mast cells, which degranulate on antigen exposure, releasing histamine
C) Cytotoxic T cells only
D) Autoantibodies against self-tissue
Question 39 (1 mark)
Live attenuated vaccines are generally contraindicated (not recommended) for which group of patients?
✎ Circle your answer
A) Healthy adults
B) Immunocompromised individuals, due to the risk of the weakened pathogen causing disease
C) Children over 10 years old
D) Pregnant animals only
Question 40 (1 mark)
Monoclonal antibodies, which are identical antibodies all specific for one epitope, are traditionally produced using:
✎ Circle your answer
A) Direct extraction from a vaccinated patient’s serum
B) Hybridoma technology, fusing an antibody-producing B cell with an immortal myeloma cell
C) PCR amplification of DNA
D) Recombination of T cell receptor genes
SECTION B — EXTENDED RESPONSE (80 marks)
Question 41 (4 marks)
Describe the sequence of events in the inflammatory response following a bacterial infection.
✎ Write your answer on paper
Question 42 (4 marks)
Compare the roles of B lymphocytes and T lymphocytes in the immune response.
✎ Write your answer on paper
Question 43 (4 marks)
Explain the clonal selection and clonal expansion of B cells following antigen exposure.
✎ Write your answer on paper
Question 44 (4 marks)
Explain how vaccines provide protection against infectious disease.
✎ Write your answer on paper
Question 45 (4 marks)
Describe how cytotoxic T cells destroy virus-infected cells.
✎ Write your answer on paper
Question 46 (4 marks)
Distinguish between active and passive immunity, giving one natural and one artificial example of each.
✎ Write your answer on paper
Question 47 (4 marks)
Explain what is meant by antigenic variation and why it makes it difficult to develop vaccines for some pathogens.
✎ Write your answer on paper
Question 48 (4 marks)
Describe the structure of an antibody (immunoglobulin). Include the variable and constant regions and explain how the structure relates to function.
✎ Write your answer on paper
Question 49 (6 marks)
<strong>Extended Response 1: Immune Response to Viral Infection (a)</strong><br>Describe the complete immune response to a new viral infection, from first exposure to resolution.
✎ Write your answer on paper
Question 50 (3 marks)
<strong>Extended Response 1: Immune Response to Viral Infection (b)</strong><br>Explain why the secondary immune response is more effective than the primary.
✎ Write your answer on paper
Question 51 (4 marks)
<strong>Extended Response 2: Vaccines and Herd Immunity (a)</strong><br>Compare traditional attenuated vaccines with mRNA vaccines. Include how each type stimulates immunity and one advantage and one disadvantage of each.
✎ Write your answer on paper
Question 52 (3 marks)
<strong>Extended Response 2: Vaccines and Herd Immunity (b)</strong><br>Explain the concept of herd immunity threshold and its significance for public health.
✎ Write your answer on paper
Extended Response 3: Type 1 Diabetes — An Autoimmune Case Study
Question 53 (3 marks)
Extended Response 3: Type 1 Diabetes — An Autoimmune Case Study (a)The table below shows typical findings from longitudinal studies of relatives of people with Type 1 diabetes, monitoring the number of different islet autoantibodies detected in blood and the percentage of individuals who progress to clinical (insulin-dependent) diabetes within 5 years.
Number of positive islet autoantibodies | 5-year progression to clinical diabetes (%)
0 | <1
1 | 15
2 | 44
3 or more | 70
Describe the trend shown in the data between the number of positive autoantibodies detected and the likelihood of progressing to clinical diabetes.
✎ Write your answer on paper
Extended Response 3: Type 1 Diabetes — An Autoimmune Case Study
Question 54 (5 marks)
Extended Response 3: Type 1 Diabetes — An Autoimmune Case Study (b)
Explain the immunological mechanism by which autoantibodies and cytotoxic T cells contribute to the destruction of insulin-producing pancreatic beta cells in Type 1 diabetes.
✎ Write your answer on paper
Extended Response 3: Type 1 Diabetes — An Autoimmune Case Study
Question 55 (4 marks)
Extended Response 3: Type 1 Diabetes — An Autoimmune Case Study (c)
Distinguish Type 1 diabetes (an autoimmune condition) from a Type I (immediate) hypersensitivity allergic reaction, with reference to the antigen involved and the immune cells/molecules primarily responsible for tissue damage.
✎ Write your answer on paper
Extended Response 3: Type 1 Diabetes — An Autoimmune Case Study
Question 56 (4 marks)
Extended Response 3: Type 1 Diabetes — An Autoimmune Case Study (d)
Explain why immunosuppressant drugs, sometimes used to slow the autoimmune attack in newly diagnosed Type 1 diabetes patients, increase the patient’s risk of opportunistic infection.
✎ Write your answer on paper
Extended Response 4: Epidemiology and Vaccination Strategy for an Emerging Respiratory Virus
Question 57 (3 marks)
Extended Response 4: Epidemiology and Vaccination Strategy for an Emerging Respiratory Virus (a)The table shows data collected during an outbreak of a novel respiratory virus as a vaccination campaign was rolled out.
Week | Vaccination coverage (%) | New cases per week (per 100,000 people)
0 | 10 | 480
10 | 40 | 310
20 | 65 | 90
30 | 82 | 15
Describe the relationship shown between rising vaccination coverage and weekly case numbers over the 30-week period.
✎ Write your answer on paper
Extended Response 4: Epidemiology and Vaccination Strategy for an Emerging Respiratory Virus
Question 58 (5 marks)
Extended Response 4: Epidemiology and Vaccination Strategy for an Emerging Respiratory Virus (b)
A subunit vaccine (containing purified viral spike protein) and an mRNA vaccine (encoding the viral spike protein) are both being trialled against this virus. Compare the way each vaccine type stimulates an adaptive immune response against the spike protein antigen.
✎ Write your answer on paper
Extended Response 4: Epidemiology and Vaccination Strategy for an Emerging Respiratory Virus
Question 59 (4 marks)
Extended Response 4: Epidemiology and Vaccination Strategy for an Emerging Respiratory Virus (c)
Explain, using the concept of antigenic drift, why a new vaccine formulation for this virus may be required in future years even if the current vaccine is highly effective now.
✎ Write your answer on paper
Extended Response 4: Epidemiology and Vaccination Strategy for an Emerging Respiratory Virus
Question 60 (4 marks)
Extended Response 4: Epidemiology and Vaccination Strategy for an Emerging Respiratory Virus (d)
The data also show that in one region, vaccination coverage fell from 82% to 55% due to vaccine hesitancy, and case numbers subsequently rose again. Given that this virus has a basic reproduction number (R0) of 4, calculate the herd immunity threshold for this virus and explain the significance of case numbers rising once coverage fell to 55%.
✎ Write your answer on paper
✓ Finished? Open the next lesson — Model Answers — to mark your work.
