Biochemistry
1 questionsClinical effect of vitamin D is reduced by ?
NEET-PG 2013 - Biochemistry NEET-PG Practice Questions and MCQs
Question 561: Clinical effect of vitamin D is reduced by ?
- A. Simultaneous ingestion of lactose
- B. Simultaneous ingestion of phytates (Correct Answer)
- C. None of the options
- D. Acidic environment
Explanation: ***Simultaneous ingestion of phytates*** - **Phytates (phytic acid)** found in whole grains, nuts, seeds, and legumes can **reduce the clinical effect of vitamin D** through multiple mechanisms - Phytates **chelate calcium** and form insoluble calcium-phytate complexes, reducing calcium absorption - Since **vitamin D and calcium metabolism are closely linked**, impaired calcium absorption indirectly reduces vitamin D efficacy - Phytates can also **directly bind to vitamin D** in the gastrointestinal tract, reducing its bioavailability - Studies show that **high phytate intake increases vitamin D requirements** and can impair vitamin D status *Simultaneous ingestion of lactose* - Lactose does **not reduce** vitamin D absorption or efficacy - In fact, **dairy products are commonly fortified** with vitamin D, and the presence of lactose does not interfere with its beneficial effects - Lactose may actually **enhance calcium absorption**, which works synergistically with vitamin D *Acidic environment* - Vitamin D is a **fat-soluble vitamin** absorbed primarily in the small intestine - An acidic environment (stomach acid) is **not known to inhibit** vitamin D absorption - The absorption process occurs in the **alkaline environment of the small intestine** where fat-soluble vitamins are absorbed with dietary fats *None of the options* - This is **incorrect** as phytates do reduce the clinical effect of vitamin D through calcium chelation and direct binding mechanisms
Microbiology
7 questionsWhat are the changes in the variable region of immunoglobulins?
Most common type of HPV associated with cervical cancer?
A plant prick can produce sporotrichosis. Which of the following statements about sporotrichosis is false?
Which of the following conditions is NOT caused by Aspergillus?
Which of the following is a cause of Valley fever (desert rheumatism)?
Which of the following statements about viruses is false?
Which is not a DNA virus?
NEET-PG 2013 - Microbiology NEET-PG Practice Questions and MCQs
Question 561: What are the changes in the variable region of immunoglobulins?
- A. Isotype
- B. Epitope
- C. Allotype
- D. Idiotype (Correct Answer)
Explanation: ***Idiotype*** - **Idiotype** refers to the unique set of antigenic determinants in the **variable region** of an antibody molecule, specifically within the **hypervariable regions (complementarity-determining regions, CDRs)**. - These unique determinants allow antibodies to recognize specific antigens and are generated by the specific **V(D)J gene rearrangements** in B cells. *Isotype* - **Isotype** refers to the constant region of an antibody, determining its class (e.g., **IgG, IgM, IgA, IgD, IgE**). - This region defines the antibody's effector functions and has nothing to do with the antigen-binding variability. *Allotype* - **Allotype** refers to minor genetic variations within the **constant region** of an antibody molecule within a species. - These variations are due to different alleles inherited from parents and are not associated with the variable region that binds to antigens. *Epitope* - An **epitope** is the specific part of an **antigen** that an antibody or T-cell receptor recognizes and binds to. - It is a feature of the antigen, not a change within the variable region of the immunoglobulin itself.
Question 562: Most common type of HPV associated with cervical cancer?
- A. 6, 11
- B. 5, 8
- C. 16, 18 (Correct Answer)
- D. 6, 8
Explanation: ***16, 18*** - **HPV types 16 and 18** are considered **high-risk HPV types** and are responsible for approximately **70% of all cervical cancer cases** globally. - These types produce **oncoproteins E6 and E7** that interfere with tumor suppressor genes (p53 and Rb), leading to uncontrolled cell growth and malignancy. *6, 11* - **HPV types 6 and 11** are considered **low-risk HPV types** and are primarily associated with **genital warts (condyloma acuminata)**. - While they can cause benign lesions, they are **rarely associated with cervical cancer**. *5, 8* - **HPV types 5 and 8** are **cutaneous HPV types** primarily associated with **epidermodysplasia verruciformis**, a rare genetic condition predisposing to skin cancers. - These types affect the **skin** and are **not associated with cervical cancer**, making them incorrect for this question. *6, 8* - This combination includes **HPV 6**, which is a **low-risk type** primarily associated with genital warts. - **HPV 8** is a cutaneous type associated with skin lesions, not cervical cancer. - This pairing does not represent the most common types responsible for cervical cancer.
Question 563: A plant prick can produce sporotrichosis. Which of the following statements about sporotrichosis is false?
- A. Enlarged lymph nodes extending centripetally as a beaded chain are a characteristic finding
- B. Most cases are acquired via cutaneous inoculation
- C. It is an occupational disease of butchers, doctors (Correct Answer)
- D. Is a chronic mycotic disease that typically involves skin, subcutaneous tissue and regional lymphatics
Explanation: ***It is an occupational disease of butchers, doctors*** - Sporotrichosis is an **occupational hazard for gardeners, florists, and agricultural workers** due to exposure to decaying plant matter, not typically for butchers or doctors. - The disease is caused by **direct inoculation** of the fungus *Sporothrix schenckii* into the skin, often through a thorn prick or minor trauma. *Most cases are acquired via cutaneous inoculation* - This statement is **true** as sporotrichosis is primarily caused by **traumatic implantation** of fungal spores into the skin. - Common sources include **thorns, splinters, sphagnum moss**, and other plant materials. *Enlarged lymph nodes extending centripetally as a beaded chain are a characteristic finding* - This statement is **true** and describes the classic **lymphocutaneous sporotrichosis**, where lesions and **nodular lymphangitis** track along lymphatic channels. - The "beaded chain" appearance refers to the multiple subcutaneous nodules formed along the lymphatic vessels. *Is a chronic mycotic disease that typically involves skin, subcutaneous tissue and regional lymphatics* - This statement is **true** because sporotrichosis is a **slow-progressing fungal infection** that primarily affects the skin, the tissue just beneath the skin, and the lymphatics draining the infected area. - While systemic dissemination can occur in immunocompromised individuals, the **cutaneous and lymphocutaneous forms** are most common.
Question 564: Which of the following conditions is NOT caused by Aspergillus?
- A. Otomycosis
- B. Dermatophytosis (Correct Answer)
- C. Allergic sinusitis
- D. Bronchopulmonary allergy
Explanation: ***Dermatophytosis*** - This condition is caused by **dermatophytes** (e.g., *Trichophyton*, *Microsporum*, *Epidermophyton*), which are a specific group of fungi that metabolize keratin. - *Aspergillus* species are generally **opportunistic molds** but do not typically cause dermatophytosis, which is a superficial fungal infection of the skin, hair, or nails. *Otomycosis* - **Otomycosis** is a fungal infection of the external ear canal, and *Aspergillus* species are a common cause, particularly *Aspergillus niger*. - It can lead to ear pain, discharge, itching, and hearing impairment. *Allergic sinusitis* - **Allergic fungal sinusitis (AFS)** is a common form of fungal sinusitis where *Aspergillus* species are significant contributors, often leading to a thick, tenacious allergic mucin. - This condition is an IgE-mediated hypersensitivity reaction to the fungal elements in the nasal and sinus cavities. *Bronchopulmonary allergy* - **Allergic bronchopulmonary aspergillosis (ABPA)** is a hypersensitivity reaction to *Aspergillus fumigatus* antigens that colonize the airways, particularly in individuals with asthma or cystic fibrosis. - It results in recurrent episodes of wheezing, cough, and transient pulmonary infiltrates, and can lead to bronchiectasis if left untreated.
Question 565: Which of the following is a cause of Valley fever (desert rheumatism)?
- A. Sporothrix
- B. Cladosporium
- C. Phialophora
- D. Coccidioides (Correct Answer)
Explanation: ***Coccidioides*** - **Valley fever**, or desert rheumatism, is caused by infection with the dimorphic fungus **Coccidioides**, primarily **Coccidioides immitis** and **Coccidioides posadasii**. - This fungus is endemic to arid and semi-arid regions, especially the **southwestern United States** and parts of Central and South America. *Sporothrix* - **Sporothrix schenckii** causes sporotrichosis, a chronic fungal infection typically involving the skin, subcutaneous tissue, and adjacent lymphatics, often through skin trauma. - It does not cause Valley fever. *Cladosporium* - **Cladosporium** species are ubiquitous molds commonly found in outdoor and indoor environments, often associated with allergic reactions and occasionally superficial infections. - They are not a cause of Valley fever. *Phialophora* - **Phialophora** species are dematiaceous fungi that can cause phaeohyphomycosis, chromoblastomycosis, and eumycetoma, which are subcutaneous or systemic fungal infections. - They are not associated with Valley fever.
Question 566: Which of the following statements about viruses is false?
- A. Viruses contain nucleic acid.
- B. Viruses lack mitochondria.
- C. Viruses are capable of independent motility. (Correct Answer)
- D. Viruses lack ribosomes.
Explanation: ***Viruses are capable of independent motility.*** - Viruses are **acellular infectious agents** and lack the cellular machinery required for independent movement or motility. - They rely on host cell processes or environmental factors for their dissemination and entry into cells. *Viruses lack ribosomes.* - Viruses are **obligate intracellular parasites**; they lack ribosomes and other cellular organelles necessary for protein synthesis. - They hijack the host cell's ribosomes and metabolic machinery to replicate their genetic material and produce viral proteins. *Viruses lack mitochondria.* - Viruses lack mitochondria, as they are **not capable of generating their own ATP** through cellular respiration. - They depend on the host cell's energy-generating systems to provide the ATP required for their replication cycle. *Viruses contain nucleic acid.* - All viruses contain a **nucleic acid genome**, which can be either DNA or RNA. - This genetic material carries the instructions for viral replication and is enclosed within a protein coat called a **capsid**.
Question 567: Which is not a DNA virus?
- A. Rhabdovirus (Correct Answer)
- B. Poxvirus
- C. Papovavirus
- D. Parvovirus
Explanation: ***Rhabdovirus*** - Rhabdoviruses, such as the rabies virus, are characterized by their **single-stranded RNA genome** and distinctive bullet-shaped morphology. - They replicate in the cytoplasm of infected cells, using their **RNA-dependent RNA polymerase** to transcribe their genome. *Papovavirus* - Papovaviruses (now split into Papillomaviridae and Polyomaviridae) are **DNA viruses** known for causing warts and some cancers. - They possess a small, **double-stranded, circular DNA genome**. *Poxvirus* - Poxviruses are large, complex **DNA viruses** that replicate entirely within the cytoplasm of the host cell. - They have a **double-stranded DNA genome** and are notable for causing diseases like smallpox and molluscum contagiosum. *Parvovirus* - Parvoviruses are among the smallest viruses, characterized by their **single-stranded DNA genome**. - They require actively dividing host cells to replicate their **linear DNA**.
Obstetrics and Gynecology
1 questionsWhich among the following is an absolute contraindication of Hormone replacement therapy?
NEET-PG 2013 - Obstetrics and Gynecology NEET-PG Practice Questions and MCQs
Question 561: Which among the following is an absolute contraindication of Hormone replacement therapy?
- A. Endometriosis
- B. Heart disease
- C. Breast carcinoma (Correct Answer)
- D. Osteoarthritis
Explanation: ### Breast carcinoma - Hormone replacement therapy (HRT) is **contraindicated** in breast carcinoma because many breast cancers are **estrogen-receptor positive**, meaning estrogen can stimulate their growth [1]. - Using HRT in patients with a history of breast cancer significantly increases the risk of **recurrence** or **progression** of the disease [1]. *Endometriosis* - Endometriosis is not an **absolute contraindication**; HRT can sometimes be used in women with a history of endometriosis, especially if a hysterectomy and bilateral oophorectomy have been performed. - However, unopposed estrogen therapy might **exacerbate** remaining endometrial implants, so a combined estrogen-progestin regimen is typically preferred [1]. *Heart disease* - While HRT has been shown to have **risks** in women with established coronary heart disease, it is not an absolute contraindication for all forms of heart disease. - The **Women's Health Initiative study** demonstrated increased cardiovascular events in older women initiating HRT, but current guidelines suggest that timing of initiation is crucial and benefits may outweigh risks for younger postmenopausal women. *Osteoarthritis* - Osteoarthritis is **not a contraindication** to HRT; in fact, some studies suggest that estrogen may have protective effects on cartilage [2]. - HRT is neither a treatment nor a contraindication for osteoarthritis and does not significantly impact its progression or severity [2].
Pediatrics
1 questionsA 3-month-old infant with no chest indrawing and a respiratory rate of 52/minute. The diagnosis is:
NEET-PG 2013 - Pediatrics NEET-PG Practice Questions and MCQs
Question 561: A 3-month-old infant with no chest indrawing and a respiratory rate of 52/minute. The diagnosis is:
- A. Severe pneumonia
- B. Pneumonia (Correct Answer)
- C. No pneumonia
- D. Very severe disease
Explanation: ***Pneumonia*** - A respiratory rate of 52/minute in a 3-month-old infant **meets the age-specific threshold for tachypnea** (respiratory rate ≥ 50 breaths/minute for infants 2-12 months according to IMCI guidelines). - In the **absence of chest indrawing**, the presence of fast breathing (tachypnea) alone classifies this as **pneumonia** per IMCI classification. - This requires **outpatient management with oral antibiotics** and close follow-up. *No pneumonia* - This diagnosis would apply if the respiratory rate was **< 50 breaths/minute** for this age group with no chest indrawing. - Since the respiratory rate is 52/minute (≥ 50/minute), this rules out "no pneumonia." *Severe pneumonia* - This diagnosis requires the presence of **chest indrawing** in addition to fast breathing. - The question explicitly states **"no chest indrawing,"** which excludes severe pneumonia. - Severe pneumonia would require **hospitalization and parenteral antibiotics**. *Very severe disease* - This diagnosis involves **danger signs** such as inability to drink or breastfeed, persistent vomiting, convulsions, lethargy, unconsciousness, or severe malnutrition. - None of these critical signs are mentioned in the clinical scenario. - Very severe disease requires **urgent hospitalization and injectable antibiotics**.