INI-CET 2026 - Biochemistry PYQs Practice Questions

Q: Elevated serum triglyceride levels are observed in all of the following conditions EXCEPT:

Abetalipoproteinemia. ***Abetalipoproteinemia*** - In this rare disorder, there is a **deficiency of apolipoprotein B**, preventing the formation and secretion of **chylomicrons**, VLDL, and LDL. - Consequently, individuals with this condition have **very low levels of serum triglycerides** and cholesterol rather than elevated levels. *Type 2 diabetes mellitus* - Insulin resistance leads to **decreased activity of lipoprotein lipase (LPL)**, the enzyme responsible for clearing triglycerides from the blood. - Increased hepatic production of **VLDL** is also typically present, leading to **hypertriglyceridemia**. *High fructose diet* - Fructose metabolism bypasses the rate-limiting step of glycolysis (PFK-1), leading to an **excess of Acetyl-CoA** in the liver. - This excess substrate promotes the synthesis of **fatty acids and VLDL**, which are subsequently secreted into the blood, raising **triglyceride levels**. *Nephrotic syndrome* - The loss of albumin in the urine triggers an **increase in hepatic lipoprotein synthesis** as a compensatory mechanism to maintain oncotic pressure. - Additionally, the urinary loss of regulatory proteins leads to **decreased catabolism of lipoproteins**, resulting in **hyperlipidemia**, predominantly involving triglycerides and LDL. [Practice more Biochemistry PYQs on OnCourse]

Q: Which molecular biotechnology is depicted in the image shown below:

CRISPR-Cas9 gene editing system. ***CRISPR-Cas9 gene editing system*** - This system utilizes a **guide RNA (gRNA)** to direct the **Cas9 endonuclease** to a specific complementary DNA sequence, creating a double-strand break. - It is a highly versatile and precise tool used for **genome editing**, enabling gene knockouts, insertions, or corrections by leveraging cellular repair mechanisms like **non-homologous end joining (NHEJ)** or **homology-directed repair (HDR)**. *Microarray analysis* - This technique involves hybridizing fluorescently labeled cDNA or cRNA samples to a chip containing thousands of **immobilized DNA probes**. - It is primarily used for **gene expression profiling** or genotyping, rather than inducing specific genetic alterations. *In situ hybridization* - This method uses labeled **DNA or RNA probes** to detect the presence and location of specific nucleic acid sequences within intact cells or tissues. - It is used for **diagnostic imaging of gene expression** or chromosomal abnormalities and does not involve gene editing activity. *DNA sequencing* - This process determines the exact **nucleotide order** of a DNA fragment, such as via the **Sanger method** or **next-generation sequencing (NGS)**. - It is a purely observational tool for reading genetic information and lacks the capacity to physically modify or cut genomic DNA. [Practice more Biochemistry PYQs on OnCourse]

Q: Which coenzyme is essential for carrying out transamination reactions in amino acid metabolism?

Pyridoxal phosphate (PLP). ***Pyridoxal phosphate (PLP)*** - PLP is the active form of **Vitamin B6** and serves as the essential cofactor for all **aminotransferases** (transaminases) that catalyze the transfer of amino groups. - The aldehyde group of PLP forms a covalent **Schiff base** intermediate with the amino acid substrate, facilitating the migration of the amino group. *Thiamine pyrophosphate (TPP)* - TPP, derived from **Vitamin B1**, acts primarily as a coenzyme for **decarboxylation** reactions, such as those performed by pyruvate dehydrogenase. - It is not involved in the transfer of amino groups between amino acids and alpha-keto acids. *Nicotinamide adenine dinucleotide (NAD)* - NAD is a coenzyme derived from **niacin (Vitamin B3)** that functions primarily as an electron carrier in **redox reactions**. - While it participates in the oxidative deamination of glutamate by glutamate dehydrogenase, it is not the primary coenzyme for transamination. *Flavin adenine dinucleotide (FAD)* - FAD, derived from **riboflavin (Vitamin B2)**, typically functions in **oxidation-reduction** reactions involving flavoproteins. - It is not involved in the transfer of amino groups in classical transamination cycles. [Practice more Biochemistry PYQs on OnCourse]

Q: Which of the following gives a negative Benedict's test?

Sucrose. ***Sucrose*** - Sucrose is a **non-reducing sugar** because the anomeric carbons of both glucose and fructose are involved in the **glycosidic bond**, leaving no free aldehyde or ketone group to reduce copper sulfate in Benedict's reagent. - Consequently, it fails to cause the characteristic **color change** from blue to brick-red, resulting in a **negative Benedict's test**. *Glucose* - Glucose is a **reducing sugar** possessing a free aldehyde group at the C1 position. - This functional group allows it to reduce cupric ions (Cu2+) to cuprous oxide (Cu+), yielding a **positive result**. *Fructose* - Despite being a ketose, fructose is a **reducing sugar** because it undergoes **tautomerization** in the alkaline conditions of the reagent to form glucose and mannose, which possess free aldehyde groups. - This chemical conversion allows it to reduce the reagent, giving a **positive result**. *Ascorbic acid* - Ascorbic acid (Vitamin C) acts as a **strong reducing agent** due to its enediol group. - Because of its potent **reducing properties**, it causes a false **positive Benedict's test** even in the absence of reducing sugars. [Practice more Biochemistry PYQs on OnCourse]

Q: Match the following: 1. Metabolic acidosis a. Hyperventilation 2. Metabolic alkalosis b. Bronchopneumonia 3. Respiratory acidosis c. Pyloric stenosis 4. Respiratory alkalosis d. Glycol poisoning

1-d, 2-c, 3-b, 4-a. ***1-d, 2-c, 3-b, 4-a*** - **Metabolic acidosis** (1-d) is correctly paired with **Glycol poisoning** (e.g., ethylene glycol), which leads to the accumulation of organic acids causing a **high anion gap metabolic acidosis**. - **Metabolic alkalosis** (2-c) is caused by **pyloric stenosis** due to the excessive loss of **gastric hydrochloric acid** through vomiting. - **Respiratory acidosis** (3-b) occurs in **bronchopneumonia** due to impaired gas exchange and **hypoventilation**, leading to **CO2 retention**. - **Respiratory alkalosis** (4-a) results from **hyperventilation** (e.g., due to anxiety or high altitude), which causes excessive **exhalation of CO2**. *1-c, 2-d, 3-b, 4-a* - Matches 1 (Metabolic acidosis) to Pyloric stenosis, which is incorrect; **pyloric stenosis** causes **metabolic alkalosis** due to vomiting of H+ ions. - Fails to correctly pair metabolic alkalosis with its specific etiology, making this option physiologically inaccurate. *1-c, 2-d, 3-a, 4-b* - Incorrectly identifies **pyloric stenosis** (2-c) as a cause of metabolic acidosis; it is a classic cause of **metabolic alkalosis**. - Mismatches the respiratory conditions, incorrectly pairing **bronchopneumonia** with respiratory alkalosis instead of **respiratory acidosis**. *1-a, 2-c, 3-b, 4-d* - Incorrectly pairs **Metabolic acidosis** with hyperventilation; hyperventilation causes **respiratory alkalosis**. - Inaccurately associates respiratory alkalosis with glycol poisoning, which actually results in severe **metabolic acidosis**. [Practice more Biochemistry PYQs on OnCourse]

Question 1

Elevated serum triglyceride levels are observed in all of the following conditions EXCEPT:

Accepted Answer

Abetalipoproteinemia

Answer

Type 2 diabetes mellitus

Answer

High fructose diet

Answer

Nephrotic syndrome

Question 2

Which molecular biotechnology is depicted in the image shown below:

Accepted Answer

CRISPR-Cas9 gene editing system

Answer

Microarray analysis

Answer

In situ hybridization

Answer

DNA sequencing

Question 3

Which coenzyme is essential for carrying out transamination reactions in amino acid
metabolism?

Accepted Answer

Pyridoxal phosphate (PLP)

Answer

Thiamine pyrophosphate (TPP)

Answer

Nicotinamide adenine dinucleotide (NAD)

Answer

Flavin adenine dinucleotide (FAD)

Question 4

Which of the following gives a negative Benedict's test?

Accepted Answer

Sucrose

Answer

Glucose

Answer

Fructose

Answer

Ascorbic acid

Question 5

Match the following:

1. Metabolic acidosis a. Hyperventilation
2. Metabolic alkalosis b. Bronchopneumonia
3. Respiratory acidosis c. Pyloric stenosis
4. Respiratory alkalosis d. Glycol poisoning

Accepted Answer

1-d, 2-c, 3-b, 4-a

Answer

1-c, 2-d, 3-b, 4-a

Answer

1-c, 2-d, 3-a, 4-b

Answer

1-a, 2-c, 3-b, 4-d

Question 6

Match the following:

1. Most essential fatty acid a. Safflower oil
2. Amino acid (AA) score b. Protein scoring system
3. Oil rich in essential fatty acid c. Protein quality + digestibility
4. Net Protein Utilization (NPU) d. Linoleic acid

Accepted Answer

1-d, 2-b, 3-a, 4-c

Answer

1-d, 2-c, 3-a, 4-b

Answer

1-b, 2-d, 3-c, 4-a

Answer

1-a, 2-b, 3-d, 4-c

Question 7

Assertion: The structural diversity of glycans exceeds that of proteins.
Reason: Glycans are not assembled using a genetic template and can form branched chains with
variable linkages.

Accepted Answer

Both A and R are true, and R is the correct explanation of A

Answer

A is true, but R is false

Answer

A is false, but R is true

Answer

Both A and R are true, but R is not the correct explanation of A

Question 8

Which of the following enzymes are active in the dephosphorylated state?
1. Glycogen synthase
2. Glycogen phosphorylase
3. Fructose-2,6-bisphosphatase
4. Phosphofructokinase-2 (PFK-2)

Accepted Answer

1 and 4

Answer

1 and 2

Answer

2 and 3

Answer

3 and 4

Question 9

In DNA replication, which enzyme synthesizes RNA primers?

Accepted Answer

Primase

Answer

Topoisomerase

Answer

DNA polymerase II

Answer

DNA polymerase III

Question 10

Which of the following amino acid classifications are correctly matched?
1. Uncharged polar AA - Cysteine
2. Nonpolar AA - Histidine
3. Basic AA - Proline
4. Basic AA - Lysine

Accepted Answer

A and D

Answer

A and B

Answer

C and D

Answer

B and C

INI-CET 2026 — Biochemistry