NEET-PG 2024 - Biochemistry PYQs Practice Questions

Q: A 45-year-old patient presents with symptoms of anemia, depigmented hair, and myelopathy. Which of the following mineral deficiencies is most likely associated with this clinical presentation?

Copper. ***Copper*** - **Copper deficiency** can lead to anemia due to its role in iron metabolism, **depigmented hair** (achromotrichia) due to impaired melanin synthesis, and **myelopathy** due to its involvement in maintaining the myelin sheath. - Symptoms often mimic those of **vitamin B12 deficiency**, including neurological manifestations like ataxia and spasticity. *Iron* - **Iron deficiency** is the most common cause of anemia but does not typically cause **depigmented hair** or **myelopathy**. - Its neurological symptoms are usually limited to **restless legs syndrome** and **pica**, not demyelination. *Fluoride* - **Fluoride deficiency** is primarily associated with an increased risk of dental caries and does not cause anemia, hair depigmentation, or myelopathy. - Excessive intake (fluorosis) can lead to **bone and tooth abnormalities**. *Zinc* - **Zinc deficiency** can cause immune dysfunction, **dermatitis**, impaired wound healing, and growth retardation. - It may rarely cause anemia in severe cases but does not typically cause hair depigmentation or myelopathy as primary symptoms. *Selenium* - **Selenium deficiency** is associated with **Keshan disease** (cardiomyopathy) and **Kashin-Beck disease** (osteoarthropathy). - While it can cause muscle weakness and fatigue, it does not typically present with the specific triad of anemia, hair depigmentation, and myelopathy seen in copper deficiency. [Practice more Biochemistry PYQs on OnCourse]

Q: A patient presents with symptoms of dermatitis, dementia, and cognitive decline. Which micronutrient deficiency is most likely responsible?

Niacin. ***Niacin*** - The classic triad of symptoms known as the "3 Ds"—**dermatitis, dementia, and diarrhea**—is characteristic of **pellagra**, a severe deficiency of **niacin (vitamin B3)**. - **Cognitive decline** is a common manifestation of the neurological symptoms associated with dementia in pellagra. *Thiamine* - **Thiamine (vitamin B1)** deficiency causes **beriberi**, leading to cardiovascular (wet beriberi) or neurological (dry beriberi/Wernicke-Korsakoff syndrome) symptoms. - While **fatigue and cognitive impairment** can occur, the constellation of prominent dermatitis and severe dementia is not typical of primary thiamine deficiency. *Tryptophan* - **Tryptophan** is an **essential amino acid** and a precursor to niacin. A deficiency in tryptophan could indirectly lead to niacin deficiency. - However, the direct deficiency of tryptophan as the primary cause of the "3 Ds" is less common than a direct niacin deficiency or impaired niacin synthesis. *Retinol* - **Retinol (vitamin A)** deficiency primarily affects **vision**, leading to **night blindness** and xerophthalmia. - It also plays a role in immune function and epithelial cell integrity, but it does not cause the specific triad of dermatitis, dementia, and cognitive decline seen here. *Riboflavin* - **Riboflavin (vitamin B2)** deficiency causes **angular stomatitis, cheilosis, and glossitis** along with seborrheic dermatitis. - While it can cause skin manifestations, it does not typically present with the severe dementia and cognitive decline characteristic of pellagra. [Practice more Biochemistry PYQs on OnCourse]

Question 1

A 45-year-old patient presents with symptoms of anemia, depigmented hair, and myelopathy. Which of the following mineral deficiencies is most likely associated with this clinical presentation?

Accepted Answer

Copper

Answer

Iron

Answer

Fluoride

Answer

Zinc

Answer

Selenium

Question 2

An infant presents with vomiting after feeding. Benedict's test was positive for a non-glucose reducing substance. What is the most likely diagnosis?

Accepted Answer

Galactosemia due to GAL-1-P Uridyl Transferase enzyme deficiency

Answer

Fructosuria due to Fructokinase deficiency

Answer

Hereditary fructose intolerance due to Aldolase B deficiency

Answer

Primary lactose intolerance

Answer

Glycogen storage disease due to Glucose-6-phosphatase deficiency

Question 3

Which disease will show the mode of inheritance depicted in this pedigree?

Accepted Answer

Achondroplasia

Answer

Prader-Willi syndrome

Answer

Wilson disease

Answer

Wiskott-Aldrich syndrome

Answer

Hemophilia A

Question 4

A mother brings her 14 -year-old mentally retarded son to the OPD, who is suffering from joint pain and has an irresistible urge to bite his fingers and lips. His serum uric acid level was found to be elevated. What is the disorder?

Accepted Answer

Lesch-Nyhan syndrome

Answer

Xanthine oxidase deficiency

Answer

CPS II defect

Answer

Thymidylate synthetase

Answer

Von Gierke disease

Question 5

A patient presents with symptoms of dermatitis, dementia, and cognitive decline. Which micronutrient deficiency is most likely responsible?

Accepted Answer

Niacin

Answer

Thiamine

Answer

Tryptophan

Answer

Retinol

Answer

Riboflavin

Question 6

A 5-year-old girl was washing her doll with shampoo containing rotenone. Her mother noticed her in an unconscious state. Which enzyme is inhibited by the above chemical?

Accepted Answer

NADH dehydrogenase

Answer

Succinate dehydrogenase

Answer

Cytochrome C

Answer

Cytochrome oxidase

Answer

Cytochrome b-c1 complex

Question 7

A patient with high triglycerides (TG) esterified with long-chain fatty acids (LCFA) presents with fatigue, and a biopsy of the muscle shows fat vacuoles. What is the most likely diagnosis?

Accepted Answer

Carnitine deficiency

Answer

Fatty acid synthase defect

Answer

Lipoprotein lipase (LPL) defect

Answer

LDL defect

Answer

Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency

Question 8

A patient presents with xanthomas on the Achilles tendon. What is the most likely diagnosis?

Accepted Answer

Familial hypercholesterolemia

Answer

Tangier's disease

Answer

Familial hyperchylomicronemia

Answer

Familial dysbetalipoproteinemia

Answer

Familial combined hyperlipidemia

Question 9

What is the source of Vitamin B1 (Thiamine)?

Accepted Answer

C

Answer

A

Answer

B

Answer

D

Answer

E

Question 10

A patient has multiple tendon xanthomas. Serum cholesterol ( $398 \mathrm{mg} / \mathrm{dL}$ ) and LDL ( 220 $\mathrm{mg} / \mathrm{dL}$ ) were found to be elevated. What is the most likely defect?

Accepted Answer

LDL receptor defect

Answer

Lipoprotein lipase deficiency

Answer

Apo E defect

Answer

LCAT deficiency

Answer

Apo B-100 defect

NEET-PG 2024 — Biochemistry