The decrease in which immune cell count is a hallmark of the transition from HIV to AIDS?
- Neutrophils
- Monocytes
- CD8 cells
- CD4 cells
Explanation: A person is clinically diagnosed with AIDS when their CD4 (Helper T-cell) count drops below a specific threshold (usually 200 cells per microliter).
Which specialized group of viruses is known to cause cancer in humans?
- Retroviruses
- Oncogenic viruses
- Bacteriophages
- Rhinoviruses
Explanation: Oncogenic viruses have genes called viral oncogenes that can trigger the transformation of normal cells into cancerous ones.
Which chemical carcinogen present in tobacco smoke is strongly linked to lung cancer?
- Citric acid
- Gluten
- Benzopyrene
- Caffeine
Explanation: Tobacco smoke contains several carcinogens, including benzopyrene, which damages the p53 gene that normally prevents cancer.
In the TNM staging system for cancer, what does the 'M' represent?
- Malignancy
- Metastasis
- Muscle
- Mutation
Explanation: The TNM system evaluates the Tumor size (T), Lymph Node involvement (N), and Distant Metastasis (M).
The genome of the Human Immunodeficiency Virus (HIV) consists of:
- Double stranded RNA
- Single stranded DNA
- Single stranded RNA
- Double stranded DNA
Explanation: HIV is a retrovirus that carries two identical copies of single-stranded RNA (ssRNA) as its genetic material.
What does the 'S' stand for in the acronym 'AIDS'?
- Syndrome
- Sickness
- System
- Symptom
Explanation: AIDS stands for Acquired Immuno Deficiency Syndrome. A 'syndrome' refers to a group of symptoms or signs that collectively characterize a disease.
The 'Western Blot' test is clinically utilized for which purpose in HIV diagnosis?
- Blood grouping
- Curing infection
- Confirmation
- Initial screening
Explanation: If a person tests positive in an ELISA screening, a more specific Western Blot test is performed to confirm the HIV infection.
Which tumor marker is clinically screened to detect potential 'Prostate Cancer'?
Explanation: PSA (Prostate-Specific Antigen) levels in the blood are used as a screening tool for prostate cancer detection and monitoring.
A tumor that remains confined to its original location without spreading to other parts is:
- Malignant
- Benign
- Metastatic
- Neoplastic
Explanation: Benign tumors are localized and generally do not invade surrounding tissues or spread to distant sites, unlike malignant tumors.
Magnetic Resonance Imaging (MRI) is preferred for cancer detection because it uses:
- Strong magnetic fields
- Ionizing radiation
- Radioactive isotopes
- High energy X-rays
Explanation: MRI uses strong magnetic fields and non-ionizing radiation to accurately detect pathological and physiological changes in living tissues.
Which type of HIV is the most common and virulent cause of the global pandemic?
Explanation: HIV-1 is the predominant strain worldwide. HIV-2 is less virulent and largely confined to West Africa.
What is the primary goal of 'Palliative Care' in advanced cancer cases?
- Complete cure
- Vaccination
- Removing tumors
- Pain management
Explanation: Palliative care focuses on improving the quality of life for patients with life-threatening illnesses by relieving symptoms and pain.
The structural protein that forms the 'capsid' or core of the HIV virus is:
- gp120
- Integrase
- Reverse transcriptase
- p24
Explanation: The p24 protein is the major structural component of the HIV capsid, used as a marker in early diagnostic tests.
Cancer of the lymph nodes and spleen is medically categorized as:
- Lymphoma
- Leukemia
- Carcinoma
- Sarcoma
Explanation: Lymphomas are cancers that originate in the cells of the immune system, specifically in the lymphatic system.
The study of the 'Epigenetics' in cancer focuses on changes that:
- Repair the skin
- Alter DNA sequence
- Kill the virus
- Don't alter sequence
Explanation: Epigenetics involves changes in gene expression (like methylation) that occur without any alteration to the underlying DNA sequence.
Cancer of the epithelial tissues (like skin or internal organ linings) is termed:
- Lymphoma
- Carcinoma
- Sarcoma
- Leukemia
Explanation: Carcinomas are the most common type of cancer, originating from epithelial cells. Sarcomas originate from mesodermal tissues like bone or muscle.
The specific DNA sequence found in normal cells that can cause cancer if mutated is:
Explanation: C-onc (cellular oncogenes) are the proto-oncogenes present in every normal cell that have the potential to cause cancer.
Which of the following is commonly known as 'Blood Cancer'?
- Melanoma
- Sarcoma
- Leukemia
- Carcinoma
Explanation: Leukemia is a cancer of the blood-forming tissues, including bone marrow, resulting in an abnormal increase in white blood cells.
The time lag between HIV infection and the appearance of AIDS symptoms can vary from:
- One week
- Few hours
- Months to years
- Always ten years
Explanation: The incubation period for AIDS is quite long, typically ranging from 5 to 10 years, though it can be shorter in some cases.
Which virus is a major causative agent for 'Cervical Cancer' in women?
- HIV
- Rhinovirus
- Hepatitis B
- Human Papilloma Virus
Explanation: High-risk strains of HPV (Human Papilloma Virus) are responsible for almost all cases of cervical cancer worldwide.
The integration of viral DNA into the host's genome is catalyzed by which HIV enzyme?
- Ligase
- Integrase
- Polymerase
- Protease
Explanation: Integrase is the enzyme that inserts the double-stranded viral DNA, produced by reverse transcription, into the host cell's DNA.
Sarcomas are cancers that arise from which embryonic germ layer?
- Endoderm
- Epiderm
- Mesoderm
- Ectoderm
Explanation: Sarcomas are malignant tumors of connective tissues like bone, cartilage, and fat, which are derived from the mesoderm.
Which organization in India is primarily responsible for AIDS awareness and control programs?
- NACO
- CSIR
- ICMR
- NITI Aayog
Explanation: The National AIDS Control Organisation (NACO) was established by the Ministry of Health and Family Welfare to lead India's response to the HIV/AIDS epidemic.
Which of the following is a common 'opportunistic' infection seen in advanced AIDS patients?
- Toxoplasmosis
- Cholera
- Common cold
- Typhoid
Explanation: As immunity weakens, patients become susceptible to infections by pathogens like Mycobacterium, viruses, fungi, and parasites like Toxoplasma.
Vertical transmission of HIV refers to the spread of the virus from:
- Human to animal
- Animal to human
- Mother to child
- Sibling to sibling
Explanation: Vertical transmission can occur during pregnancy, during childbirth (parturition), or through breastfeeding (lactation).
The HIV/AIDS (Prevention and Control) Act in India was passed in which year?
Explanation: The 2017 Act provides a legal framework to prevent discrimination against people living with HIV and ensures their right to healthcare.
Which diagnostic technique involves the microscopic study of a thin slice of suspected tissue?
- Radiography
- MRI
- Biopsy
- CT scan
Explanation: In a biopsy, a piece of suspected tissue is taken and thin sections are stained and examined under a microscope (histopathology) by a pathologist.
Which specific enzyme allows HIV to synthesize viral DNA from its RNA template?
- Reverse transcriptase
- RNA polymerase
- Helicase
- DNA polymerase
Explanation: Reverse transcriptase catalyzes the formation of DNA from an RNA template, a process that is characteristic of retroviruses.
Which of the following is a tumor of the 'pigment-producing' cells of the skin?
- Sarcoma
- Adenoma
- Leukemia
- Melanoma
Explanation: Melanoma is the most serious type of skin cancer, developing in the melanocytes that produce the pigment melanin.
What does 'PrEP' stand for in the context of HIV prevention strategy?
- Pre-Exposure Prophylaxis
- Post-Entry Phase
- Primary Entry Protein
- Protease Entry Point
Explanation: PrEP is a strategy where people at very high risk for HIV take daily medicine to prevent the virus from establishing an infection.
In the human body, which cells are primarily targeted and destroyed by HIV?
- Helper T-cells
- Cytotoxic T-cells
- Natural killer cells
- B-lymphocytes
Explanation: HIV infects and replicates within Helper T-lymphocytes (CD4 cells), leading to a progressive decrease in their count and the eventual failure of the immune system.
Computed Tomography (CT) utilizes which of the following to generate 3D images of internal organs?
- Magnetic resonance
- X-rays
- Infrared light
- Sound waves
Explanation: CT scans use X-rays to create cross-sectional and 3D images of the internal structures of the body to detect tumors.
The 'p53' gene is known as the 'Guardian of the Genome' because it is a/an:
- Viral gene
- Oncogene
- Structural gene
- Tumor suppressor
Explanation: The p53 protein regulates the cell cycle and prevents the replication of cells with damaged DNA, thus suppressing tumor formation.
Which of the following is a potential 'chemical' carcinogen found in preserved or smoked meats?
- Nitrosamines
- Lactose
- Vitamin C
- Fructose
Explanation: Nitrosamines are chemical compounds that can be carcinogenic; they are often formed from nitrates used as preservatives in processed meats.
A 'Pap smear' is a common screening test used specifically for:
- Cervical cancer
- HIV antibodies
- Prostate health
- Breast cancer
Explanation: The Papanicolaou (Pap) smear involves collecting cells from the cervix to look for changes that might indicate pre-cancer or cancer.
The enzyme that allows cancer cells to avoid 'cellular aging' and divide indefinitely is:
- Lipase
- Telomerase
- Amylase
- Pepsin
Explanation: Telomerase maintains the length of telomeres (chromosome ends), allowing cancer cells to bypass the normal limit of cell division.
The 'Window Period' in HIV infection refers to the time during which:
- Virus is dead
- Symptoms are visible
- Patient is cured
- Tests are negative
Explanation: The window period is the time between potential exposure to HIV and the point when a test can accurately detect the virus or antibodies.
Which of the following physical agents is strictly classified as an ionizing carcinogen capable of causing neoplastic transformation?
- Infrared radiation
- Ultraviolet rays
- Visible light spectrum
- High-energy X-rays
Explanation: Carcinogens are agents that cause cancer. Ionizing radiations like X-rays and gamma rays carry enough energy to detach electrons from atoms, causing direct DNA damage and neoplastic transformation. Ultraviolet (UV) rays, conversely, are non-ionizing carcinogens.
The procedure of 'Bone Marrow Transplant' is most commonly used to treat:
- Brain tumors
- Skin cancer
- Leukemia
- Lung cancer
Explanation: BMT replaces damaged or destroyed bone marrow with healthy stem cells, used primarily in blood-related cancers like leukemia.
Which of the following describes the biological process 'Angiogenesis' in cancer?
- Nerve signaling
- Muscle repair
- Blood vessel growth
- Cell death
Explanation: Tumors stimulate the formation of new blood vessels (angiogenesis) to supply themselves with nutrients and oxygen for rapid growth.
In HIV therapy, 'Nucleoside Reverse Transcriptase Inhibitors' (NRTIs) work by:
- Killing T-cells
- Blocking DNA chain
- Lowering body temp
- Dissolving viral coat
Explanation: NRTIs are faulty building blocks that, when incorporated into viral DNA by reverse transcriptase, cause premature termination of the DNA chain.
Which of the following is NOT a recognized mode of HIV transmission?
- Sexual contact
- Blood transfusion
- Placental transfer
- Mosquito bites
Explanation: HIV is not a vector-borne disease; it is transmitted through body fluids (blood, semen, vaginal secretions) and cannot survive or replicate in mosquitoes.
World AIDS Day is observed globally on:
- December 1
- June 5
- July 11
- April 7
Explanation: December 1st is dedicated to raising awareness of the AIDS pandemic caused by the spread of HIV infection.
Which of the following is a 'biological response modifier' used to activate the immune system against tumors?
- Antibiotics
- Histamine
- Morphine
- Alpha-interferon
Explanation: Alpha-interferon is an immunotherapy agent that helps the immune system recognize and destroy tumor cells.
The widely used clinical diagnostic test for the initial screening of AIDS is:
- Western Blot
- ELISA
- Widal test
- MRI
Explanation: Enzyme-Linked Immuno-sorbent Assay (ELISA) is the standard biochemical screening test used to detect HIV antibodies in the blood.
Which of the following cells is often referred to as the 'HIV factory' in an infected person?
- Stem cells
- Erythrocytes
- Helper T-cells
- Macrophages
Explanation: Macrophages continue to produce viral particles for a long duration after infection without being immediately destroyed, thus acting as a reservoir or 'factory' for the virus.
Which rare skin cancer is a classic 'AIDS-defining' illness caused by a herpes virus?
- Melanoma
- Lymphoma
- Kaposi's sarcoma
- Basal carcinoma
Explanation: Kaposi's sarcoma (KS) is caused by Human Herpesvirus 8 (HHV-8) and is frequently seen in severely immunocompromised AIDS patients.
Which specific glycoprotein on the HIV surface binds to the CD4 receptor of T-cells?
- gp120
- Reverse transcriptase
- gp41
- p24
Explanation: The gp120 envelope protein of HIV specifically recognizes and binds to the CD4 receptor on the surface of Helper T-cells and macrophages.
Which 'inert' gas is a known environmental carcinogen that can cause lung cancer in houses?
Explanation: Radon gas, produced by the natural decay of uranium in soil, can accumulate in buildings and is the leading cause of lung cancer in non-smokers.
The use of 'Monoclonal Antibodies' to target specific cancer cells is a part of:
- Targeted therapy
- Radiotherapy
- Surgery
- Chemotherapy
Explanation: Targeted therapy uses drugs or antibodies to specifically identify and attack cancer cells while causing less damage to normal cells.
Genes present in normal cells that can lead to oncogenic transformation if activated are:
- Proto-oncogenes
- Silent genes
- V-oncogenes
- Structural genes
Explanation: Proto-oncogenes (or cellular oncogenes) are normal genes that regulate cell growth. Mutations can turn them into active oncogenes, leading to cancer.
Treatment of cancer using high-energy radiation to kill tumor cells is called:
- Cryotherapy
- Radiotherapy
- Immunotherapy
- Chemotherapy
Explanation: Radiotherapy involves the controlled use of radiation to damage the DNA of cancer cells, preventing them from dividing.
Which of the following is a non-ionizing carcinogen?
- Cosmic rays
- X-rays
- Gamma rays
- UV radiation
Explanation: UV radiation is non-ionizing but carries enough energy to cause thymine dimers in DNA, leading to skin cancer.
Anti-retroviral therapy (ART) is used in AIDS treatment primarily to:
- Kill the virus
- Prolong life
- Vaccinate others
- Cure the disease
Explanation: While ART can effectively reduce the viral load and prolong the patient's life, it cannot completely eliminate the virus from the body or 'cure' AIDS.
What is the primary objective of Post-Exposure Prophylaxis (PEP) for HIV?
- Killing T-cells
- Permanent cure
- Preventing infection
- Increasing weight
Explanation: PEP involve taking antiretroviral medicines after being potentially exposed to HIV to prevent the virus from establishing an infection.
The property of malignant tumors where cells slough off and start new tumors at distant sites is:
- Mutation
- Infiltration
- Metastasis
- Angiogenesis
Explanation: Metastasis is the most feared property of cancer, where cells reach distant organs via blood or lymph and establish secondary tumors.
The screening method that uses 'sound waves' instead of radiation to visualize tumors is:
- PET scan
- Ultrasonography
- CT scan
- X-ray
Explanation: Ultrasonography uses high-frequency sound waves (ultrasound) to create images of internal organs without using ionizing radiation.
Cancer cells lose a regulatory property found in normal cells known as:
- Signal transduction
- Apoptosis
- Cellular adhesion
- Contact inhibition
Explanation: Normal cells stop dividing when they come in contact with other cells. Cancer cells lose this 'contact inhibition' and continue to divide uncontrollably, forming masses of cells (tumors).
Which of the following is a common side effect of intensive chemotherapy?
- Hair loss
- Better vision
- Stronger immunity
- Weight gain
Explanation: Chemotherapy drugs target rapidly dividing cells. Since hair follicle cells also divide quickly, hair loss (alopecia) is a common side effect.
Which diagnostic test detects the 'p24 antigen' of HIV to allow earlier detection?
- Antibody ELISA
- Widal test
- Western Blot
- 4th Gen ELISA
Explanation: 4th Generation ELISA tests detect both HIV antibodies and the p24 viral protein, reducing the window period for diagnosis.