UPSC-CMS 2022 — Biochemistry

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: Consider the protein content of the following food items (in terms of grams per 100 grams of food) : 1. Cow milk 2. Meat 3. Soya bean 4. Sugar What is the correct descending order (highest to lowest) of protein content?

3 → 2 → 1 → 4. ***Correct Option: 3 → 2 → 1 → 4*** - **Soya bean** has the highest protein content at approximately **36-40 grams per 100 grams**, making it one of the richest plant-based protein sources - **Meat** (chicken, beef) follows with **20-30 grams of protein per 100 grams** depending on the cut and type - **Cow milk** contains approximately **3.2-3.5 grams of protein per 100 grams** - **Sugar** is a pure carbohydrate with **0 grams of protein** *Incorrect Option: 2 → 3 → 4 → 1* - Places meat before soya bean, but soya bean has higher protein content than most meats - Incorrectly places cow milk last (milk has more protein than sugar) *Incorrect Option: 2 → 1 → 3 → 4* - Incorrectly places soya bean third, when it should be first as the highest protein source - Underestimates the exceptional protein content of soya beans *Incorrect Option: 3 → 1 → 2 → 4* - Incorrectly places cow milk before meat - Meat has significantly more protein (~20-30g) compared to milk (~3-3.5g) [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]

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

Consider the protein content of the following food items (in terms of grams per 100 grams of food) : 1. Cow milk 2. Meat 3. Soya bean 4. Sugar What is the correct descending order (highest to lowest) of protein content?

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

UPSC-CMS 2022 - Biochemistry UPSC-CMS Practice Questions and MCQs

Question 1: The single most sensitive tool for evaluating the iron status in an individual is

A. serum iron concentration
B. haemoglobin concentration
C. serum ferritin value (Correct Answer)
D. serum transferrin saturation

Explanation: ***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.

Question 2: Consider the protein content of the following food items (in terms of grams per 100 grams of food) : 1. Cow milk 2. Meat 3. Soya bean 4. Sugar What is the correct descending order (highest to lowest) of protein content?

A. 2 → 3 → 4 → 1
B. 3 → 2 → 1 → 4 (Correct Answer)
C. 2 → 1 → 3 → 4
D. 3 → 1 → 2 → 4

Explanation: ***Correct Option: 3 → 2 → 1 → 4*** - **Soya bean** has the highest protein content at approximately **36-40 grams per 100 grams**, making it one of the richest plant-based protein sources - **Meat** (chicken, beef) follows with **20-30 grams of protein per 100 grams** depending on the cut and type - **Cow milk** contains approximately **3.2-3.5 grams of protein per 100 grams** - **Sugar** is a pure carbohydrate with **0 grams of protein** *Incorrect Option: 2 → 3 → 4 → 1* - Places meat before soya bean, but soya bean has higher protein content than most meats - Incorrectly places cow milk last (milk has more protein than sugar) *Incorrect Option: 2 → 1 → 3 → 4* - Incorrectly places soya bean third, when it should be first as the highest protein source - Underestimates the exceptional protein content of soya beans *Incorrect Option: 3 → 1 → 2 → 4* - Incorrectly places cow milk before meat - Meat has significantly more protein (~20-30g) compared to milk (~3-3.5g)

Question 3: Of the following amino acids required by the human body, which one falls under the category of 'essential' amino acid?

A. Arginine
B. Threonine (Correct Answer)
C. Proline
D. Serine

Explanation: ***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.