UPSC-CMS 2022 - Biochemistry PYQs Practice Questions

Q: In hyperemesis gravidarum, Wernicke's encephalopathy is seen due to the deficiency of

vitamin B1. ***vitamin B1*** - **Wernicke's encephalopathy** is directly caused by a severe deficiency of **thiamine (vitamin B1)**. - In **hyperemesis gravidarum**, persistent vomiting leads to inadequate intake and absorption of this vital vitamin. *vitamin B6* - Deficiency of **vitamin B6 (pyridoxine)** can cause peripheral neuropathy, glossitis, and dermatitis. - While important for many metabolic processes, its deficiency is not directly linked to Wernicke's encephalopathy. *vitamin B12* - **Vitamin B12 (cobalamin)** deficiency primarily results in megaloblastic anemia and subacute combined degeneration of the spinal cord. - It does not cause the specific neurological triad of Wernicke's encephalopathy. *vitamin B9* - Deficiency of **vitamin B9 (folate)** leads to megaloblastic anemia and is crucial for neural tube development. - It is not associated with the pathogenesis of Wernicke's encephalopathy. [Practice more Biochemistry PYQs on OnCourse]

Q: The single most sensitive tool for evaluating the iron status in an individual is

serum ferritin value. ***serum ferritin value*** - **Serum ferritin** directly reflects the size of the body's iron stores and is the most sensitive indicator of **iron deficiency** in the preclinical stage. - A low serum ferritin value is highly specific for diagnosing **iron deficiency** before anemia develops. *serum iron concentration* - **Serum iron concentration** fluctuates throughout the day and is affected by many factors, making it a poor sole indicator of overall **iron status**. - It can be normal even in early stages of **iron deficiency** due to compensatory mechanisms. *haemoglobin concentration* - **Hemoglobin concentration** only falls in the late stages of **iron deficiency**, once **iron deficiency anemia** has developed. - It does not reflect early **iron depletion** or iron-deficient erythropoiesis. *serum transferrin saturation* - **Serum transferrin saturation** (TSAT) measures the amount of iron bound to transferrin and transporting iron, but it is less sensitive than ferritin for detecting early **iron deficiency**. - TSAT can be influenced by inflammation and other medical conditions, potentially masking true iron status. [Practice more Biochemistry PYQs on OnCourse]

Q: Of the following amino acids required by the human body, which one falls under the category of 'essential' amino acid?

Threonine. ***Threonine*** - **Threonine** is one of the nine **essential amino acids** that the human body cannot synthesize on its own. - It must be obtained through the **diet** to support protein synthesis and other vital bodily functions. *Arginine* - **Arginine** is generally considered a **conditionally essential** or **semi-essential amino acid**. - While the body can synthesize it, requirements may increase during periods of rapid growth, illness, or stress, making dietary intake important in those situations. *Proline* - **Proline** is a **non-essential amino acid**, meaning the human body can synthesize it from other precursors. - It plays a crucial role in the structure of **collagen** and connective tissue. *Serine* - **Serine** is also a **non-essential amino acid** that can be synthesized by the human body. - It is involved in the metabolism of fats, fatty acids, and the synthesis of various other biomolecules. [Practice more Biochemistry PYQs on OnCourse]

Question 1

In hyperemesis gravidarum, Wernicke's encephalopathy is seen due to the deficiency of

Accepted Answer

vitamin B1

Answer

vitamin B6

Answer

vitamin B12

Answer

vitamin B9

Question 2

The single most sensitive tool for evaluating the iron status in an individual is

Accepted Answer

serum ferritin value

Answer

serum iron concentration

Answer

haemoglobin concentration

Answer

serum transferrin saturation

Question 3

Of the following amino acids required by the human body, which one falls under the category of 'essential' amino acid?

Accepted Answer

Threonine

Answer

Arginine

Answer

Proline

Answer

Serine

UPSC-CMS 2022 — Biochemistry