INI-CET 2026 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.

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.

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.

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.

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**.

Q: 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

1-d, 2-b, 3-a, 4-c. ***1-d, 2-b, 3-a, 4-c*** - **1-d**: **Linoleic acid** (an omega-6 fatty acid) is considered the most essential fatty acid because the human body cannot synthesize it and must obtain it through the diet. - **2-b**: The **amino acid (AA) score** is a **protein scoring system** that compares the content of the limiting amino acid in a specific food protein to the content of the same amino acid in a reference protein (like egg or human milk). - **3-a**: **Safflower oil** is recognized as a rich source of **polyunsaturated fatty acids**, specifically **linoleic acid** (an essential fatty acid). - **4-c**: **Net Protein Utilization (NPU)** measures both the **protein quality** (amino acid composition) and the **digestibility** of the protein source, representing the proportion of nitrogen intake that is retained in the body. *1-d, 2-c, 3-a, 4-b* - Incorrect because the mapping of the amino acid score to protein quality plus digestibility is inaccurate; those specific components describe **Net Protein Utilization (NPU)** or **Protein Digestibility Corrected Amino Acid Score (PDCAAS)** rather than simply the AA score. - The mapping of 4-b (NPU to Protein scoring system) is too generic, as NPU specifically accounts for nitrogen retention and digestibility, not just a basic score. *1-b, 2-d, 3-c, 4-a* - Incorrect because this matches the essential fatty acid (1) to the protein scoring system, which is factually unrelated. - Additionally, it incorrectly matches the oil source to the NPU metric, which is a physiological measurement of protein usage, not an oil. *1-a, 2-b, 3-d, 4-c* - Incorrect because safflower oil (a) is not the *most* essential fatty acid; linoleic acid (d) is the chemical substance classified as the essential fatty acid. - The internal mapping here misattributes biochemical definitions to the wrong category, failing to align the essential nutrient with its correct oil source.

Q: Identify the skin receptor shown in the image:

Pacinian corpuscle. ***Pacinian corpuscle*** - These are **large, encapsulated mechanoreceptors** characterized by a distinctive 'onion-like' appearance due to multiple concentric lamellae of connective tissue. - Located deep in the dermis and subcutaneous tissue, they are specifically adapted to detect **high-frequency vibration** and deep pressure. *Merkel disc* - These are non-encapsulated receptors located in the **stratum basale** of the epidermis. - They function primarily as **slowly adapting** receptors responsible for sensing **fine touch** and texture. *Ruffini ending* - These appear as spindle-shaped receptors located deep within the dermis and joint capsules. - They are **slowly adapting** mechanoreceptors that detect **skin stretch** and sustained pressure. *Meissner corpuscle* - These are encapsulated receptors located in the **dermal papillae** of glabrous (hairless) skin. - They are **rapidly adapting** receptors that specialize in detecting **low-frequency vibration** and light touch.

Q: Intercalated disc is composed of: 1. Cadherins 2. Desmosomes 3. Gap junctions 4. Tight junctions

1, 2 and 3. ***1, 2 and 3*** - Intercalated discs contain **fascia adherens** (containing **cadherins**) and **desmosomes** which provide strong mechanical adhesion, preventing cells from separating during contraction. - **Gap junctions** are essential components of the intercalated disc, allowing for the rapid passage of ions and electrical impulses, which facilitates **functional syncytium** behavior of cardiac muscle. *2, 3 and 4* - While desmosomes and gap junctions are correct, **tight junctions** are not typically components of the intercalated disc. - Tight junctions function primarily to create permeability barriers in epithelial and endothelial tissues, not in contractile cardiac muscle. *1, 3 and 4* - While cadherins and gap junctions are correct, **tight junctions** are not present in cardiac intercalated discs. - Tight junctions are characteristic of the **blood-brain barrier** or intestinal lining, meant for regulating paracellular transport. *1, 2, 3 and 4* - Including **tight junctions** makes this option incorrect, as they are not structural components of the cardiac intercalated disc. - The intercalated disc is specialized for mechanical cohesion and electrical coupling, not for maintaining epithelial-like tight barrier functions.

Q: Which of the following statements regarding hormones and their metabolic actions are correct? A. Insulin increases protein synthesis B. Thyroxine decreases basal metabolic rate C. Insulin decreases blood glucose levels D. Epinephrine increases glycogenolysis E. Glucagon increases gluconeogenesis

A, C, D and E only. ### ***A, C, D and E only*** - **Insulin** acts as a potent anabolic hormone, stimulating amino acid uptake and intracellular **protein synthesis**, while simultaneously lowering **blood glucose levels** by facilitating glucose uptake into tissues like skeletal muscle and adipose tissue. - **Epinephrine** stimulates glycogen breakdown (**glycogenolysis**) in the liver and muscle for rapid energy, while **Glucagon** elevates blood glucose by promoting **gluconeogenesis** and glycogenolysis, primarily in the liver. *A, B and C only* - This option includes **Thyroxine**, which is incorrect because thyroid hormones are key regulators that **increase the basal metabolic rate (BMR)**, not decrease it. - Therefore, any set containing statement B is fundamentally incorrect. *A, C and D only* - While A, C, and D are correct, this combination is incomplete because statement **E (Glucagon increases gluconeogenesis)** is medically accurate. - Omitting statement E makes this option inferior to the fully comprehensive answer. *All of the above* - This option is incorrect because it includes statement B, which contradicts the established physiological role of **Thyroxine**. - Thyroxine is calorigenic and consistently acts to raise the body's **metabolic rate**.

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

Identify the skin receptor shown in the
image:

Accepted Answer

Pacinian corpuscle

Answer

Merkel disc

Answer

Ruffini ending

Answer

Meissner corpuscle

Question 9

Intercalated disc is composed of:

1. Cadherins
2. Desmosomes
3. Gap junctions
4. Tight junctions

Accepted Answer

1, 2 and 3

Answer

2, 3 and 4

Answer

1, 3 and 4

Answer

1,2, 3 and 4

Question 10

Which of the following statements regarding hormones and their metabolic actions are correct?

A. Insulin increases protein synthesis
B. Thyroxine decreases basal metabolic rate
C. Insulin decreases blood glucose levels
D. Epinephrine increases glycogenolysis
E. Glucagon increases gluconeogenesis

Accepted Answer

A, C, D and E only

Answer

A, B and C only

Answer

A, C and D only

Answer

All of the above

INI-CET 2026

Biochemistry

Physiology