Form Four Biology Exam - HIV/AIDS (With Marking Scheme)

FORM FOUR BIOLOGY EXAMINATION – TOPIC: HIV/AIDS

Time: 3 Hours

Instructions:

• Answer all questions in Sections A and B.
• Answer two (2) questions only from Section C.
• Write neatly and use diagrams where necessary.

SECTION A (16 Marks)

1. Multiple Choice Questions (10 Marks)

Choose the correct answer:

1. The virus that causes AIDS mainly affects:
   • a) Red blood cells
   • b) T-helper cells
   • c) Platelets
   • d) Phagocytes
2. PLWHA stands for:
   • a) People Living With Health Awareness
   • b) Patients Living With Human Allergy
   • c) People Living With HIV and AIDS
   • d) Protection of Life With Health Assistance
3. A function of T-helper cells is:
   • a) Destroying red blood cells
   • b) Producing insulin
   • c) Stimulating immune responses
   • d) Transporting oxygen
4. HIV is classified as a:
   • a) Bacterium
   • b) Protozoan
   • c) Retrovirus
   • d) Fungal pathogen
5. Which of the following is a non-transmission mode of HIV?
   • a) Unprotected sex
   • b) Sharing clothes
   • c) Sharing needles
   • d) Mother-to-child
6. HIV can be diagnosed by:
   • a) Skin check
   • b) Urine test
   • c) Blood test
   • d) X-ray
7. Opportunistic infections are common in:
   • a) Athletes
   • b) People with strong immunity
   • c) PLWHA
   • d) Pregnant women
8. Responsible behavior towards PLWHA includes:
   • a) Isolation
   • b) Sharing their medication
   • c) Encouraging stigma
   • d) Providing care and empathy
9. The role of VCT includes:
   • a) Increasing HIV spread
   • b) Counseling and testing
   • c) Providing vaccines
   • d) Avoiding blood donations
10. T-helper cells are destroyed during HIV infection leading to:
    • a) Muscle weakness
    • b) Immune system failure
    • c) Dehydration
    • d) Bone damage

2. Matching Items (6 Marks)

Match the items in List A with the correct responses in List B:

List A	List B
(i) T-helper cells	a) A person who has tested positive for HIV
(ii) Immune suppression	b) Medication that slows HIV multiplication
(iii) PLWHA	c) A condition due to low immunity
(iv) Opportunistic infection	d) Virus attacking immune cells
(v) Antiretroviral therapy	e) White cells coordinating immune defense
(vi) HIV virus	f) Disease exploiting weakened immunity

SECTION B (54 Marks)

3. T-helper Cells and HIV (9 Marks)

1. What are the roles of T-helper cells in immunity? (4 marks)
2. Explain how HIV affects these cells and its consequences. (5 marks)

4. Misconceptions and Support for PLWHA (9 Marks)

1. Identify and explain two misconceptions Ali has about PLWHA. (4 marks)
2. Suggest three responsible ways to support PLWHA in society. (5 marks)

5. HIV Transmission and VCT (9 Marks)

1. Mention three body fluids that can transmit HIV. (3 marks)
2. Describe two major functions of VCT in HIV prevention. (6 marks)

6. Opportunistic Infections (9 Marks)

1. Why are opportunistic infections common in HIV-positive people? (4 marks)
2. Give three examples of such infections and explain how they affect PLWHA. (5 marks)

7. Importance of ARVs (9 Marks)

1. What are ARVs and how do they help PLWHA? (5 marks)
2. Why is strict adherence to ARV treatment important? (4 marks)

8. Emotional and Social Support for PLWHA (9 Marks)

1. Explain the importance of emotional and social support for PLWHA. (4 marks)
2. Describe three ways to reduce stigma against PLWHA in schools. (5 marks)

SECTION C (30 Marks)

Answer any two (2) questions.

9. HIV Infection Mechanism (15 Marks)

Describe the infection mechanism of HIV from entry into the body to the destruction of the immune system. Include the role of T-helper cells.

10. Impact of Stigma on PLWHA (15 Marks)

Discuss the impact of stigma on PLWHA and propose five ways to promote a positive and inclusive environment.

11. Importance of VCT (15 Marks)

Explain the importance of regular HIV testing and counseling services (VCT), and how they contribute to HIV prevention and care.

FORM FOUR BIOLOGY EXAMINATION – ANSWERS: HIV/AIDS

Time: 3 Hours

SECTION A (16 Marks)

1. Multiple Choice Questions (10 Marks)

1. The virus that causes AIDS mainly affects:
   • b) T-helper cells
2. PLWHA stands for:
   • c) People Living With HIV and AIDS
3. A function of T-helper cells is:
   • c) Stimulating immune responses
4. HIV is classified as a:
   • c) Retrovirus
5. Which of the following is a non-transmission mode of HIV?
   • b) Sharing clothes
6. HIV can be diagnosed by:
   • c) Blood test
7. Opportunistic infections are common in:
   • c) PLWHA
8. Responsible behavior towards PLWHA includes:
   • d) Providing care and empathy
9. The role of VCT includes:
   • b) Counseling and testing
10. T-helper cells are destroyed during HIV infection leading to:
    • b) Immune system failure

2. Matching Items (6 Marks)

List A	List B
(i) T-helper cells	e) White cells coordinating immune defense
(ii) Immune suppression	c) A condition due to low immunity
(iii) PLWHA	a) A person who has tested positive for HIV
(iv) Opportunistic infection	f) Disease exploiting weakened immunity
(v) Antiretroviral therapy	b) Medication that slows HIV multiplication
(vi) HIV virus	d) Virus attacking immune cells

SECTION B (54 Marks)

3. T-helper Cells and HIV (9 Marks)

1. Roles of T-helper cells:
   • Activate B-cells to produce antibodies.
   • Stimulate cytotoxic T-cells to attack infected cells.
   • Coordinate immune responses via cytokine release.
   • Enhance macrophage activity to engulf pathogens.
2. HIV effects and consequences:
   • HIV infects T-helper cells using CD4 receptors.
   • Virus replicates, destroying T-helper cells.
   • Reduced T-helper cells weaken immune coordination.
   • Leads to immune suppression, increasing opportunistic infections.
   • Progression to AIDS if untreated, causing severe illness.

4. Misconceptions and Support for PLWHA (9 Marks)

1. Misconceptions:
   • HIV spreads through casual contact (e.g., touching): It requires specific body fluids like blood or semen.
   • PLWHA are always infectious: Proper treatment reduces transmission risk.
2. Ways to support PLWHA:
   • Provide emotional support through empathy and understanding.
   • Educate communities to reduce stigma and discrimination.
   • Ensure access to healthcare and social services.

5. HIV Transmission and VCT (9 Marks)

1. Body fluids for HIV transmission:
   • Blood
   • Semen
   • Breast milk
2. Functions of VCT:
   • Testing: Identifies HIV status for early intervention and treatment.
   • Counseling: Educates on prevention, treatment, and coping, reducing risky behaviors.

6. Opportunistic Infections (9 Marks)

1. Why common in HIV-positive people:
   • HIV destroys T-helper cells, weakening immunity.
   • Low immunity allows pathogens to proliferate.
   • Reduced immune coordination fails to control infections.
   • Opportunistic pathogens exploit compromised defenses.
2. Examples and effects:
   • Tuberculosis: Causes lung damage, severe coughing, and weight loss.
   • Pneumocystis pneumonia: Leads to breathing difficulties and fever.
   • Candidiasis: Causes oral or esophageal infections, hindering swallowing.

7. Importance of ARVs (9 Marks)

1. ARVs and benefits:
   • Antiretrovirals inhibit HIV replication.
   • Slow disease progression to AIDS.
   • Restore T-helper cell counts, improving immunity.
   • Reduce viral load, lowering transmission risk.
   • Improve quality of life for PLWHA.
2. Importance of adherence:
   • Prevents viral resistance to ARVs.
   • Maintains low viral load for health.
   • Ensures consistent immune system support.
   • Reduces risk of treatment failure.

8. Emotional and Social Support for PLWHA (9 Marks)

1. Importance of support:
   • Emotional support reduces stress and depression.
   • Social support fosters inclusion and acceptance.
   • Encourages adherence to treatment.
   • Improves mental and physical well-being.
2. Ways to reduce stigma in schools:
   • Educate students on HIV facts to dispel myths.
   • Promote inclusive activities involving PLWHA.
   • Train teachers to support and protect PLWHA.

SECTION C (30 Marks)

Answers for Questions 9 and 11.

9. HIV Infection Mechanism (15 Marks)

• HIV enters via blood, semen, or other fluids.
• Attaches to T-helper cells via CD4 receptors.
• Viral RNA integrates into host DNA using reverse transcriptase.
• Replicates within T-helper cells, producing new virions.
• Infected cells burst, releasing viruses to infect others.
• T-helper cell count declines, impairing immune coordination.
• Immune system weakens, leading to opportunistic infections.
• Progresses to AIDS without treatment, causing severe immune failure.

11. Importance of VCT (15 Marks)

• Early detection enables timely ARV treatment.
• Counseling educates on prevention, reducing transmission.
• Encourages behavior change, like safe sex practices.
• Supports PLWHA with coping strategies and care access.
• Reduces stigma through education and awareness.
• Facilitates monitoring of HIV prevalence in communities.
• Links PLWHA to treatment and support services.