Biochemistry
2 questionsMost Common enzyme deficient in galactosemics:
Chaperones are:
FMGE 2018 - Biochemistry FMGE Practice Questions and MCQs
Question 61: Most Common enzyme deficient in galactosemics:
- A. Galactosidase
- B. UDP galactose epimerase
- C. Galactokinase
- D. Galactose-1-phosphate uridyl transferase/GALT (Correct Answer)
Explanation: ***Galactose-1-phosphate uridyl transferase/GALT*** - **GALT deficiency** is the most common cause of **classic galactosemia** (Type I), a severe inherited metabolic disorder. - This enzyme is crucial for converting **galactose-1-phosphate** to **glucose-1-phosphate** in the main pathway of galactose metabolism. - Accounts for approximately **95%** of all galactosemia cases. *Galactosidase* - **Galactosidase** enzymes are involved in the hydrolysis of galactose-containing oligosaccharides or glycoconjugates but are not the primary enzymes deficient in classic galactosemia. - This enzyme is not part of the Leloir pathway of galactose metabolism, which is the pathway affected in galactosemia. *UDP galactose epimerase* - Deficiency of **UDP galactose epimerase** (GALE) causes a milder form of galactosemia (Type III), but it is much less common than GALT deficiency. - GALE is involved in the interconversion of UDP-galactose and UDP-glucose. - This is the rarest form of galactosemia. *Galactokinase* - **Galactokinase deficiency** (GALK) causes a different, milder form of galactosemia (Type II), characterized by **cataracts** as the primary symptom. - It prevents the initial phosphorylation of galactose to galactose-1-phosphate. - This accounts for less than 5% of galactosemia cases.
Question 62: Chaperones are:
- A. Mediators of post-translational assembly of protein complexes (Correct Answer)
- B. Antigen presenting cells
- C. Purine metabolism mediators
- D. None of the above
Explanation: ***Mediators of post-translational assembly of protein complexes*** - **Chaperones** are proteins that assist in the proper folding of other proteins, especially new polypeptides, and in the assembly of **protein complexes** after translation. - They prevent **misfolding** and aggregation of proteins, ensuring their correct functional conformation. *Antigen presenting cells* - **Antigen-presenting cells (APCs)** are immune cells (e.g., macrophages, dendritic cells) that present **antigens** to T cells for recognition. - Their primary function is in the **immune response**, not protein folding or assembly. *Purine metabolism mediators* - **Purine metabolism mediators** are enzymes or molecules involved in the synthesis, breakdown, and recycling of **purines (adenine and guanine)**. - This function is entirely distinct from the role of chaperones in **protein folding**. *None of the above* - This option is incorrect because the first option accurately describes the function of **chaperones**.
Microbiology
2 questionsClassical complement is activated by:
In Plasmodium vivax malaria, relapse is caused by:
FMGE 2018 - Microbiology FMGE Practice Questions and MCQs
Question 61: Classical complement is activated by:
- A. C3 Convertase
- B. C1
- C. Ag-Ab complex (Correct Answer)
- D. IgA
Explanation: ***Ag-Ab complex*** - The **classical complement pathway** is initiated by the binding of **C1q** to an antigen-antibody complex, specifically involving **IgM** or certain subclasses of **IgG**. - This binding triggers a cascade of events leading to the activation of the complement system, ultimately resulting in the **lysis of target cells**, **opsonization**, and **inflammation**. *C3 Convertase* - **C3 convertase** is an enzyme complex formed later in the complement cascade, responsible for cleaving C3 into C3a and C3b. - While essential for all complement pathways, it is a **downstream effector** and not the initial activator of the classical pathway. *C1* - **C1** is a complex protein that includes C1q, C1r, and C1s. While C1 plays a crucial role in the classical pathway, it is **activated by** the antigen-antibody complex, not an independent activator. - The activation sequence is: **Ag-Ab complex → C1q binding → C1 activation → cascade initiation**. Thus, the Ag-Ab complex is the primary trigger, and C1 is the responder. *IgA* - **IgA** primarily functions in mucosal immunity and is generally **not an activator** of the classical complement pathway. - Instead, IgA can activate the **alternative complement pathway** under specific circumstances, but not the classical pathway through direct binding to C1q.
Question 62: In Plasmodium vivax malaria, relapse is caused by:
- A. Hypnozoite (Correct Answer)
- B. Schizont
- C. Sporozoite
- D. Gametocyte
Explanation: ***Hypnozoite*** - **Hypnozoites** are dormant forms of *Plasmodium vivax* and *P. ovale* that persist in the liver for months to years after initial infection. - These dormant hepatic stages can later reactivate, develop into merozoites, and cause a **relapse** of malaria symptoms even after successful treatment of the blood-stage infection. - Relapses are a defining feature of *P. vivax* malaria and require treatment with **primaquine** or **tafenoquine** for radical cure to eliminate hypnozoites. *Incorrect: Schizont* - **Schizonts** are stages where asexual reproduction occurs, either in liver cells (hepatic schizonts) or red blood cells (erythrocytic schizonts). - Erythrocytic schizonts cause acute malaria symptoms but do not cause delayed relapses as they are cleared by standard antimalarial treatments. - Hepatic schizonts complete their cycle within 1-2 weeks and do not remain dormant. *Incorrect: Sporozoite* - **Sporozoites** are the infective stage injected by the mosquito that travel to the liver to initiate infection. - They differentiate into either developing schizonts or dormant hypnozoites but do not directly cause relapses. - Sporozoites represent the initial infection, not the mechanism of relapse. *Incorrect: Gametocyte* - **Gametocytes** are the sexual stage found in human blood that are ingested by mosquitoes to continue the parasite lifecycle. - They are responsible for transmission to mosquitoes but do not cause human symptoms or relapses in the host. - Gametocytes do not remain dormant in the liver.
Obstetrics and Gynecology
1 questionsHighest Contraceptive failure is reported in
FMGE 2018 - Obstetrics and Gynecology FMGE Practice Questions and MCQs
Question 61: Highest Contraceptive failure is reported in
- A. Implant
- B. IUD
- C. Oral contraceptive pills
- D. Spermicidal methods (Correct Answer)
Explanation: ***Spermicidal methods*** - **Spermicides** have a significantly higher failure rate compared to other contraceptive methods because their effectiveness relies heavily on **correct and consistent application** before each act of intercourse. - Their efficacy is often compromised by improper use, short duration of action, or failure to adequately kill sperm, leading to a higher chance of **unintended pregnancy**. *Implant* - Contraceptive **implants** (e.g., etonogestrel implant) are among the most effective contraceptive methods, with a very low failure rate due to **continuous hormone release**. - They offer **long-acting reversible contraception (LARC)**, eliminating user error upon insertion. *IUD* - **Intrauterine devices (IUDs)**, both hormonal and copper, are highly effective LARC methods with very low failure rates. - Their effectiveness is independent of user adherence after insertion, making them **highly reliable**. *Oral contraceptive pills* - **Oral contraceptive pills** are effective when used perfectly, but their typical use effectiveness is lower than implants or IUDs due to the possibility of **user error**, such as missing pills. - **Adherence** to a daily regimen is crucial for their efficacy.
Orthopaedics
1 questionsMost common site of osteomyelitis in children
FMGE 2018 - Orthopaedics FMGE Practice Questions and MCQs
Question 61: Most common site of osteomyelitis in children
- A. Epiphysis
- B. Metaphysis (Correct Answer)
- C. Growth plate
- D. Diaphysis
Explanation: ***Metaphysis*** - The **metaphysis** is the most common site for osteomyelitis in children due to its rich, **slow-flowing sinusoidal blood supply**, which facilitates bacterial seeding. - The **nutrient arteries** in the metaphysis make sharp loops, creating a turbulent flow that slows circulation and allows bacteria to lodge more easily. *Epiphysis* - The **epiphysis** is less commonly affected in children because its separate blood supply is not as prone to bacterial seeding as the metaphysis. - In infants, however, infection can spread from the metaphysis to the epiphysis and joint space due to **transphyseal vessels**. *Growth plate* - The **growth plate** itself is generally resistant to infection due to its avascular nature. - However, infection in the adjacent metaphysis or epiphysis can potentially disrupt its function. *Diaphysis* - While the **diaphysis** has a blood supply, it is less common for osteomyelitis to originate here compared to the metaphysis. - It usually occurs as a secondary spread from a metaphyseal infection or in specific scenarios like in **sickle cell disease**.
Pathology
2 questionsMarble bone disease is:
Most common benign breast tumour:
FMGE 2018 - Pathology FMGE Practice Questions and MCQs
Question 61: Marble bone disease is:
- A. Osteosclerosis
- B. Histiocytosis X
- C. Osteopetrosis (Correct Answer)
- D. Osteomalacia
Explanation: ***Osteopetrosis*** - **Osteopetrosis**, also known as **marble bone disease**, is a rare genetic disorder characterized by abnormally dense bones due to a defect in **osteoclast function** [1]. - Impaired bone resorption leads to an accumulation of woven bone, causing bones to be fragile despite their density [1]. *Osteosclerosis* - **Osteosclerosis** is a general term for increased bone density and can be a feature of various conditions, including osteopetrosis. - However, it is a descriptive term rather than a specific disease diagnosis equivalent to marble bone disease. *Histiocytosis X* - **Histiocytosis X**, also known as **Langerhans cell histiocytosis**, is a rare disorder involving the proliferation of Langerhans cells. - It primarily affects bone but can also involve other organs, presenting with lytic lesions rather than increased bone density. *Osteomalacia* - **Osteomalacia** is a condition characterized by inadequate mineralization of bone tissue, leading to soft and weakened bones. - It is typically caused by **vitamin D deficiency** and is the opposite of increased bone density. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1188-1189.
Question 62: Most common benign breast tumour:
- A. Phyllodes tumour
- B. Fibroadenosis
- C. DCIS
- D. Fibroadenoma (Correct Answer)
Explanation: ***Fibroadenoma*** - **Fibroadenomas** are the **most common benign breast tumors**, typically presenting as mobile, firm, and non-tender masses [1]. - They are composed of both **glandular and stromal tissue** and are more prevalent in younger women [1]. *Phyllodes tumour* - **Phyllodes tumors** are much **rarer** than fibroadenomas and can be benign, borderline, or malignant [3]. - They tend to grow **rapidly** and are characterized by a leaf-like stromal pattern [3]. *Fibroadenosis* - **Fibroadenosis** (or fibrocystic changes) refers to a collection of **benign changes** in the breast tissue, including cysts, fibrosis, and epithelial hyperplasia, rather than a single tumor [2]. - It is a common condition causing lumpy and painful breasts, especially before menstruation [4]. *DCIS* - **Ductal Carcinoma In Situ (DCIS)** is a **non-invasive form of breast cancer** where abnormal cells are confined to the milk ducts. - It is not a benign tumor and carries a risk of progression to invasive breast cancer. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 448-449. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 445-446. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Breast, p. 1074. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Breast, p. 1052.
Pharmacology
1 questionsPharmacodynamics deals with:-
FMGE 2018 - Pharmacology FMGE Practice Questions and MCQs
Question 61: Pharmacodynamics deals with:-
- A. Latency of onset
- B. Mechanism of action of a drug (Correct Answer)
- C. Transport of drug across the biological membranes
- D. Mode of excretion of a drug
Explanation: Detailed study of the **Mechanism of action of a drug** [1][2] - **Pharmacodynamics** describes what the **drug does to the body**, including its **molecular targets** and biochemical effects [3]. - This involves the study of the drug's mechanisms to produce its therapeutic or toxic effects [2]. *Latency of onset* - **Latency of onset** refers to the time it takes for a drug to start producing its effects, which is a pharmacokinetic rather than a pharmacodynamic parameter. - It deals with the drug's absorption and distribution rather than its interaction with the body once it reaches its site of action. *Transport of drug across the biological membranes* - The **transport of drugs across biological membranes** is a key aspect of **pharmacokinetics**, specifically absorption and distribution [1]. - This process determines how much drug reaches its target site, not how it interacts with the target. *Mode of excretion of a drug* - The **mode of excretion** of a drug (e.g., renal, hepatic) falls under **pharmacokinetics**, addressing how the body gets rid of the drug. - This process influences the drug's duration of action and elimination half-life, not its mechanism of action.
Physiology
1 questionsCold water is not used for ear cleaning because
FMGE 2018 - Physiology FMGE Practice Questions and MCQs
Question 61: Cold water is not used for ear cleaning because
- A. Damage to tympanic membrane
- B. It will cause infection
- C. Caloric stimulation caused by cold water (Correct Answer)
- D. It will make the wax hard
Explanation: ***Caloric stimulation caused by cold water*** - Irrigating the ear canal with **cold water** causes significant **caloric stimulation** of the vestibular system. - This can induce **vertigo**, **nausea**, and **vomiting** due to the temperature difference stimulating the semicircular canals. *Damage to tympanic membrane* - While excessive pressure from irrigation can potentially damage the **tympanic membrane**, the temperature of the water itself is not the primary factor for this risk. - Damage is more related to the **force of irrigation** and pre-existing membrane integrity, not cold temperature. *It will cause infection* - The temperature of the water used for irrigation does not directly determine the risk of infection. - **Infection risk** is primarily associated with using unsterile water or introducing bacteria into a compromised ear canal, regardless of water temperature. *It will make the wax hard* - Earwax, or **cerumen**, is softened by water irrigation, not hardened. - **Warm water** is typically preferred because it aids in softening the wax more effectively and comfortably than cold water.