Question 26:

Which of the following statements are correct?

(A) DNA microarray is a collection of DNA sequences immobilized on a solid surface that can be probed by hybridization.
(B) Differential centrifugation describes the separation of cell organelles by different rates of sedimentation.
(C) Amino acids that cannot be synthesized by humans but are synthesized by microbes are called essential amino acids.
(D) Equilibrium constant is specific for each chemical reaction.

Choose the correct answer from the options given below:

(A) (A), (B) and (C) only
(B) (A), (B) and (D) only
(C) (A), (C) and (D) only
(D) (B), (C) and (D) only

Question 27:

Read the following statements carefully:

(A) DNA ligases are enzymes that create a phosphodiester bond between DNA fragments.
(B) A protein containing one or more prosthetic groups is called a conjugated protein.
(C) A type of enzyme inhibition reversed by increasing the substrate concentration is called competitive inhibition.
(D) Two stereoisomers of a given sugar that differ only in the configuration about carbonyl carbon atom are called anomers.

Choose the correct answer from the options given below:

(A) (A), (B) and (C) only
(B) (A), (B) and (D) only
(C) (A), (C) and (D) only
(D) (B), (C) and (D) only

Correct Answer: (C) (A), (C) and (D) only

View Solution

(A) Correct: DNA ligases form phosphodiester bonds to join DNA fragments, crucial for replication and repair.
(B) Incorrect: Conjugated proteins contain prosthetic groups, but this is not relevant to the correct answer in this context.
(C) Correct: Competitive inhibition is reversible by increasing substrate concentration, a key feature of this type of inhibition.
(D) Correct: Anomers are stereoisomers of sugars differing at the carbonyl carbon atom (anomeric carbon).

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Question 28:

A researcher engineers a lac operon on a plasmid inactivating all parts of the lac operator and the lac promoter, replacing them with the binding site for the LexA repressor and promoter regulated by LexA. The plasmid is introduced into E.coli cells that have a lac operon with an inactive lacZ gene. Under what conditions will these transformed cells produce β-galactosidase?

(A) On subjecting E.coli cells to high levels of a DNA-damaging agent like UV light
(B) On starving E.coli cells
(C) On growing E.coli cells in lactose-rich medium
(D) On co-culturing E.coli cells with B subtilis

Correct Answer: (A) On subjecting E.coli cells to high levels of a DNA-damaging agent like UV light

View Solution

The LexA protein represses genes in the SOS response pathway. Under DNA damage (e.g., UV light), LexA is cleaved, allowing transcription of genes it regulates. This engineering enables the production of β-galactosidase in response to LexA degradation caused by DNA damage.

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Question 29:

Which one of the following is the basis for protein structural classification?

(A) Length
(B) Genus
(C) Composition
(D) Motif

Correct Answer: (D) Motif

View Solution

Protein structures are classified based on recurring structural motifs, which are common arrangements of secondary structures like α-helices and β-sheets. Motifs are crucial for determining protein function and interactions.

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Question 30:

The catabolic lysosomal degradation of cellular proteins is called:

(A) Phagocytosis
(B) Autophagy
(C) Chaperon
(D) Autotroph

Correct Answer: (B) Autophagy

View Solution

Autophagy is a process where lysosomes degrade and recycle cellular components, including proteins, to maintain cellular homeostasis. It is vital for responding to stress and removing damaged organelles or misfolded proteins.

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Question 31:

Which one of the following i.e., number of molecules per gram molecular weight, represents the Avogadro’s number (N)?

(A) 6.02 × 10⁶
(B) 6.02 × 10⁷
(C) 6.02 × 10²³
(D) 6.02 × 10³³

Correct Answer: (C) 6.02 × 10²³

View Solution

Avogadro’s number, N_A, is defined as the number of molecules (or atoms) in one mole of a substance. It has a fixed value of 6.022 × 10²³ molecules/mol.

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Question 32:

The energy derived from noncovalent interactions between enzyme and substrate is called:

(A) Bond energy
(B) Activation energy
(C) Binding energy
(D) Entropy

Correct Answer: (C) Binding energy

View Solution

Binding energy is the energy released from noncovalent interactions between an enzyme and its substrate. This energy helps stabilize the enzyme-substrate complex and lower the activation energy of the reaction.

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Question 33:

One calorie (cal) equals to how many joules (J)?

(A) 2.18
(B) 4.18
(C) 6.18
(D) 7.18

Correct Answer: (B) 4.18

View Solution

1 calorie is equivalent to 4.18 joules. This is the energy required to raise the temperature of 1 gram of water by 1°C.

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Question 34:

Match List I with List II:

List I Protein Name	List II Molecular Weight (kDa)
A. β-galactosidase	(ii) 116.25
B. Bovine Serum Albumin	(iv) 66.2
C. Ovalbumin	(i) 14.4
D. Lysozyme	(iii) 45

Choose the correct answer from the options given below:

(A) (A) - (IV), (B) - (III), (C) - (II), (D) - (I)
(B) (A) - (II), (B) - (IV), (C) - (III), (D) - (I)
(C) (A) - (II), (B) - (IV), (C) - (I), (D) - (III)
(D) (A) - (II), (B) - (IV), (C) - (I), (D) - (III)

Correct Answer: (C) (A) - (II), (B) - (IV), (C) - (I), (D) - (III)

View Solution

A. β-galactosidase - (II): Its molecular weight is approximately 116.25 kDa.
B. Bovine Serum Albumin - (IV): This protein has a molecular weight of 66.2 kDa.
C. Ovalbumin - (I): Its molecular weight is 14.4 kDa.
D. Lysozyme - (III): The molecular weight is 45 kDa.

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Question 35:

The number of enzyme units per milligram of total protein is called:

(A) Activity
(B) Specific activity
(C) Kcat
(D) Km

Correct Answer: (B) Specific activity

View Solution

Specific activity refers to the enzymatic activity (units) per milligram of total protein. It is a measure of enzyme purity, with higher specific activity indicating greater purity.

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Question 36:

When a protein has two or more polypeptide subunits, their folding arrangement is called:

(A) Primary structure
(B) Secondary structure
(C) Tertiary structure
(D) Quaternary structure

Correct Answer: (D) Quaternary structure

View Solution

The quaternary structure of a protein describes the arrangement and interactions of multiple polypeptide chains (subunits) within a single protein complex. Examples include hemoglobin and collagen.

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Question 37:

When wool sweaters are washed in hot water, they shrink. In contrast, when silk clothes are washed, they do not shrink under the same conditions:

(A) The β-woolen polypeptide chains are converted to the native α-helical conformation.
(B) The structure of silk β-sheets is more stable than that of wool.
(C) The β-woolen polypeptide chains remain in their native conformation.
(D) The structure of silk β-sheets is less stable than that of the wool protein structure.

Choose the correct answer from the options given below:

(A) (A) only
(B) (A), (B) and (D) only
(C) (A), (B), (C) and (D)
(D) (B), (C) and (D) only

Correct Answer: (A) (A) only

View Solution

(A) Correct: Wool proteins, when heated, shift from their native β-sheet structure to an α-helical conformation, causing the material to shrink.
(B) Incorrect: While silk β-sheets are stable, this does not explain the behavior of wool.
(C) Incorrect: Wool’s polypeptide chains do not remain in their β-sheet conformation upon heating.
(D) Incorrect: Silk β-sheets are more stable than wool’s α-helix, but this does not directly address the question.

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Question 38:

A genetic mutation that limits the production of glucocerebrosidase, an enzyme responsible for breaking down fats, leads to which of the following diseases?

(A) Klinefelter Syndrome
(B) Phenylketonuria
(C) Gaucher’s disease
(D) Turner Syndrome

Correct Answer: (C) Gaucher’s disease

View Solution

Gaucher’s disease is caused by a mutation in the gene encoding glucocerebrosidase, leading to the accumulation of glucocerebroside in cells, particularly macrophages, and resulting in symptoms such as hepatomegaly and bone pain.

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Question 39:

Which one of the following is a disease caused by defects in enzymes necessary for heme biosynthesis?

(A) Lesch Nyhan syndrome
(B) Porphyria
(C) Huntington’s disease
(D) Marfan Syndrome

Correct Answer: (B) Porphyria

View Solution

Porphyria refers to a group of disorders caused by defects in heme biosynthesis enzymes. These defects lead to the accumulation of porphyrins, which can cause photosensitivity, abdominal pain, and neurological issues.

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Question 40:

A mutation in the GLA (alpha-galactosidase A) gene leads to which one of the following conditions?

(A) Fabry disease
(B) Gaucher disease
(C) Phenylketonuria
(D) Cri-du-chat syndrome

Correct Answer: (A) Fabry disease

View Solution

Fabry disease is caused by mutations in the GLA gene, which codes for the alpha-galactosidase A enzyme. This leads to the accumulation of globotriaosylceramide in various organs, causing symptoms such as pain, kidney failure, and cardiac issues.

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Question 41:

A group of contiguous nucleotide codons in DNA molecule that does not include a termination codon is called:

(A) Open Reading Frame
(B) Operon
(C) Genetic code
(D) Cis trans system

Correct Answer: (A) Open Reading Frame

View Solution

An open reading frame (ORF) is a sequence of DNA that begins with a start codon and extends without interruption (no stop codon) to a stop codon, representing the coding sequence for a protein.

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Question 42:

The step in an enzymatic reaction of a pathway that needs greatest amount of activation energy is called:

(A) Rate constant
(B) Rate limiting
(C) Rate enhancing
(D) Kcat

Correct Answer: (B) Rate limiting

View Solution

The rate-limiting step is the slowest step in a biochemical pathway, requiring the highest activation energy. It determines the overall rate of the reaction sequence.

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Question 43:

A sequence in an mRNA that is required for binding bacterial ribosomes is called:

(A) Short tandem repeat
(B) Long tandem repeat
(C) Shine-Dalgarno
(D) Ras

Correct Answer: (C) Shine-Dalgarno

View Solution

The Shine-Dalgarno sequence is a ribosomal binding site in bacterial mRNA, located upstream of the start codon. It aligns the ribosome with the mRNA for translation initiation.

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Question 44:

Hyponatremia is a condition where the concentration of the following ion decreases below normal level in plasma:

(A) Sodium
(B) Potassium
(C) Zinc
(D) Magnesium

Correct Answer: (A) Sodium

View Solution

Hyponatremia refers to abnormally low sodium levels in the blood, often caused by excessive fluid intake, hormonal imbalances, or kidney problems.

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Question 45:

A human condition of acid-base disturbance with high H+ ions in the blood is called:

(A) Acidosis
(B) Acidemia
(C) Alkalemia
(D) Alkalosis

Correct Answer: (B) Acidemia

View Solution

Acidemia occurs when there is an increase in hydrogen ion concentration, resulting in a blood pH below the normal range (7.35-7.45). It can be caused by metabolic or respiratory disorders.

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Question 46:

In kidneys the glomerular filtration rate (GFR) depends upon:

(A) The difference in hydrostatic and oncotic pressures between the glomerular capillaries and the lumen of the nephron.
(B) The nature of glomerular basement membrane.
(C) Total available filtration area.
(D) Relative concentration of ions.

Choose the correct answer from the options given below:

(A) (A), (B) and (C) only
(B) (A), (B) and (D) only
(C) (A), (B), (C) and (D)
(D) (B), (C) and (D) only

Correct Answer: (A) (A), (B) and (C) only

View Solution

GFR is regulated by the hydrostatic and oncotic pressures driving filtration.
It depends on the structure and function of the glomerular basement membrane.
The total filtration area available in the glomerulus also plays a critical role.

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Question 47:

A decrease in the concentration of serum albumin leads to which of the following conditions?

(A) Chronic liver disease
(B) Hemochromatosis
(C) Wilson disease
(D) Cirrhosis

Correct Answer: (A) Chronic liver disease

View Solution

Serum albumin is primarily synthesized in the liver. Decreased levels indicate liver dysfunction, as seen in chronic liver disease, affecting the liver’s ability to synthesize proteins.

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Question 48:

A patient presents herself with stunted growth, web-like neck, and an absence of X chromosome. What would be your diagnosis of this genetic condition?

(A) Down syndrome
(B) Turner syndrome
(C) Klinefelter syndrome
(D) Cri-du-chat syndrome

Correct Answer: (B) Turner syndrome

View Solution

Turner syndrome is caused by monosomy of the X chromosome (45, X), presenting with symptoms such as short stature, webbed neck, and underdeveloped sexual characteristics.

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Question 49:

Which of the following is the main cause of liver failure?

(A) Viral hepatitis
(B) Deletion of chromosome 5p
(C) Psychosomatic
(D) Low Mg²⁺ concentration

Correct Answer: (A) Viral hepatitis

View Solution

Liver failure is commonly caused by viral infections like hepatitis B and C, which damage liver cells and disrupt its functions.

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Question 50:

What is the rate of mortality in acute liver failure?

(A) 10% - 20%
(B) 30% - 40%
(C) 60% - 70%
(D) Up to 90%

Correct Answer: (D) Up to 90%

View Solution

Acute liver failure has a high mortality rate of up to 90%, particularly in cases of late-stage presentation or without timely liver transplantation.

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Question 51:

In E.coli, the enzyme that fills gaps in duplexes by stepwise addition of nucleotides to the 3’ end is called:

(A) Type II restriction endonucleases
(B) DNA polymerase I
(C) DNA ligase
(D) Terminal transferase

Correct Answer: (B) DNA polymerase I

View Solution

DNA polymerase I in E.coli is responsible for filling gaps in the DNA duplex by adding nucleotides to the 3’ hydroxyl group. It has both polymerase and exonuclease activities, enabling it to remove primers and replace them with DNA.

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Question 52:

The enzyme reverse transcriptase:

(A) Joins RNA-RNA fragments
(B) Makes a copy of DNA from an RNA molecule
(C) Removes terminal phosphates from 5’ end
(D) Cleaves RNA at random positions

Correct Answer: (B) Makes a copy of DNA from an RNA molecule

View Solution

Reverse transcriptase is an enzyme that synthesizes complementary DNA (cDNA) from an RNA template. This process is a key step in the life cycle of retroviruses like HIV.

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Question 53:

Match List I with List II:

List I: Type of Food	List II: % trans fatty acids/gram
A. French Fries	(iii) 28
B. Pizza	(iv) 9
C. Muffin	(i) 14
D. Chocolate Bar	(ii) 2

Choose the correct answer from the options given below:

(A) (A) - (I), (B) - (II), (C) - (III), (D) - (IV)
(B) (A) - (III), (B) - (IV), (C) - (I), (D) - (II)
(C) (A) - (IV), (B) - (II), (C) - (I), (D) - (III)
(D) (A) - (IV), (B) - (III), (C) - (II), (D) - (I)

Correct Answer: (B) (A) - (III), (B) - (IV), (C) - (I), (D) - (II)

View Solution

French Fries (A - III): Contain 28% trans fatty acids per gram.
Pizza (B - IV): Contains 9% trans fatty acids per gram.
Muffin (C - I): Contains 14% trans fatty acids per gram.
Chocolate Bar (D - II): Contains 2% trans fatty acids per gram.

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Question 54:

Another name for Vitamin D3 is:

(A) Retinol
(B) Dolichol
(C) Tocopherol
(D) Cholecalciferol

Correct Answer: (D) Cholecalciferol

View Solution

Vitamin D3, also known as cholecalciferol, is synthesized in the skin in response to UV radiation and plays a vital role in calcium homeostasis and bone health.

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Question 55:

Warfarin has which of the following functions?

(A) Blood anticoagulant
(B) Mitochondrial electron carrier
(C) Antioxidant
(D) A sugar carrier

Correct Answer: (A) Blood anticoagulant

View Solution

Warfarin is an anticoagulant medication that prevents blood clot formation by inhibiting the synthesis of clotting factors dependent on Vitamin K.

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Question 56:

Which of the following statements are correct?

(A) Some types of lipids play critical roles as cofactors or signals.
(B) Prostaglandins are derived from arachidonate.
(C) Steroid hormones are derived from sterols.
(D) Vitamins D, A, and E are fat-soluble.

Choose the correct answer from the options given below:

(A) (A), (B) and (D) only
(B) (A), (B) and (C) only
(C) (A), (B), (C) and (D)
(D) (B), (C) and (D) only

Correct Answer: (C) (A), (B), (C) and (D)

View Solution

(A) Correct: Lipids such as phosphatidylinositol derivatives act as cofactors or signaling molecules.
(B) Correct: Prostaglandins are synthesized from arachidonic acid, a polyunsaturated fatty acid.
(C) Correct: Steroid hormones like cortisol and testosterone are derived from cholesterol (a sterol).
(D) Correct: Vitamins D, A, E, and K are fat-soluble and stored in body fat.

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Question 57:

Phosphatidylcholine and phosphatidylserine are examples of:

(A) Fatty acids
(B) Glycerolipids
(C) Glycerophospholipids
(D) Sphingolipids

Correct Answer: (C) Glycerophospholipids

View Solution

Phosphatidylcholine and phosphatidylserine are glycerophospholipids, consisting of a glycerol backbone, two fatty acid chains, and a phosphate group with a head group (e.g., choline or serine).

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Question 58:

Match List I with List II:

List I: Category	List II: Examples
A. Fatty acids	(iv) Oleate
B. Prenol lipids	(ii) Farnesol
C. Saccharolipids	(iii) Lipopolysaccharide
D. Polyketides	(i) Tetracycline

Choose the correct answer from the options given below:

(A) (A) - (I), (B) - (III), (C) - (II), (D) - (IV)
(B) (A) - (II), (B) - (III), (C) - (IV), (D) - (I)
(C) (A) - (III), (B) - (IV), (C) - (I), (D) - (II)
(D) (A) - (IV), (B) - (II), (C) - (III), (D) - (I)

Correct Answer: (D) (A) - (IV), (B) - (II), (C) - (III), (D) - (I)

View Solution

Fatty acids (A - IV): Oleate is a fatty acid commonly found in biological systems.
Prenol lipids (B - II): Farnesol is an example of prenol lipids.
Saccharolipids (C - III): Lipopolysaccharide is a saccharolipid found in bacterial cell walls.
Polyketides (D - I): Tetracycline is a polyketide and is widely used as an antibiotic.

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Question 59:

Match List I with List II:

List I: Animal Plasma Membrane	List II: Type of Sterol
A. Human myelin sheath	(iii) Cholesterol
B. Maize leaf	(iv) Stigmasterol
C. Yeast	(ii) Ergosterol
D. Paramecium	(i) Sitosterol

Choose the correct answer from the options given below:

(A) (A) - (I), (B) - (III), (C) - (II), (D) - (IV)
(B) (A) - (II), (B) - (IV), (C) - (I), (D) - (III)
(C) (A) - (III), (B) - (IV), (C) - (II), (D) - (I)
(D) (A) - (IV), (B) - (II), (C) - (I), (D) - (III)

Correct Answer: (C) (A) - (III), (B) - (IV), (C) - (II), (D) - (I)

View Solution

Human myelin sheath (A - III): Cholesterol is the primary sterol found in animal plasma membranes, including the myelin sheath in humans.
Maize leaf (B - IV): Ergosterol is a sterol found in plants like maize.
Yeast (C - II): Stigmasterol is associated with fungal cell membranes such as in yeast.
Paramecium (D - I): Sitosterol is commonly found in protozoans like Paramecium.

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Question 60:

Match List I with List II:

List I: Ion Channel Defects	List II: Disease
A. Na+	(iii) Cystic fibrosis
B. Ca2+	(iv) Dominant deafness
C. K+	(i) Polycystic kidney disease
D. Cl	(ii) Generalized epilepsy

Choose the correct answer from the options given below:

(A) (A) - (I), (B) - (II), (C) - (III), (D) - (IV)
(B) (A) - (III), (B) - (IV), (C) - (I), (D) - (II)
(C) (A) - (II), (B) - (IV), (C) - (III), (D) - (I)
(D) (A) - (IV), (B) - (I), (C) - (II), (D) - (III)

Correct Answer: (B) (A) - (III), (B) - (IV), (C) - (I), (D) - (II)

View Solution

Na+ (A - III): Cystic fibrosis is associated with sodium ion channel defects.
Ca2+ (B - IV): Dominant deafness can be linked to calcium ion channel defects.
K+ (C - I): Polycystic kidney disease is a result of defective potassium ion channels.
Cl (D - II): Generalized epilepsy is connected to chloride ion channel dysfunction.

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Question 61:

In a substrate-enzyme reaction, the term K_d denotes which one of the following?

(A) Equilibrium constant
(B) Dissociation constant
(C) Association constant
(D) Turnover rate

Correct Answer: (C) Association constant

View Solution

The association constant (K_a) reflects the strength of binding between an enzyme and its substrate. It is inversely proportional to the dissociation constant (K_d).

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Question 62:

A metabolic condition in which the capacity of the body to buffer OH^- is diminished, is called:

(A) Acidosis
(B) Alkalosis
(C) Kurtosis
(D) Lipidosis

Correct Answer: (B) Alkalosis

View Solution

Alkalosis occurs when the body accumulates excessive OH^- ions or loses too many H⁺ ions, leading to an increase in blood pH above 7.45.

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Question 63:

Immune cells that ingest large particles and cells by phagocytosis are called:

(A) Macrophages
(B) B lymphocytes
(C) Cytotoxic T cells
(D) Helper T cells

Correct Answer: (A) Macrophages

View Solution

Macrophages are immune cells that engulf pathogens and debris via phagocytosis, playing a critical role in innate immunity and inflammation.

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Question 64:

Enzymes that are involved in the transfer of electrons (hydride ions or H atoms) are called:

(A) Transferases
(B) Hydrolases
(C) Oxidoreductases
(D) Ligases

Correct Answer: (C) Oxidoreductases

View Solution

Oxidoreductases catalyze electron transfer between molecules, facilitating redox reactions essential in cellular metabolism.

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Question 65:

Among the following enzymes, which one has the highest turnover number (k_cat)?

(A) Catalase
(B) Carbonic anhydrase
(C) Fumarase
(D) Acetylcholinesterase

Correct Answer: (A) Catalase

View Solution

Catalase has the highest turnover number, breaking down millions of hydrogen peroxide molecules per second into water and oxygen.

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Question 66:

Albinism is a genetic disorder associated with:

(A) Heart
(B) Skin
(C) Kidney
(D) Urine

Correct Answer: (B) Skin

View Solution

Albinism is caused by mutations in genes affecting melanin production, leading to pigmentation deficiency in the skin, hair, and eyes.

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Question 67:

Of the following pH values, which one is the lowest?

(A) 0
(B) 1
(C) 2
(D) 7

Correct Answer: (A) 0

View Solution

A pH of 0 indicates the highest acidity due to the highest concentration of H⁺ ions, making it the lowest value.

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Question 68:

Among the following Liver Function Tests, which one indicates hepatocellular damage?

(A) AST
(B) ALP
(C) BIL
(D) GGT

Correct Answer: (A) AST

View Solution

Aspartate Aminotransferase (AST) is an enzyme released when liver cells are damaged, serving as a marker for hepatocellular damage.

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Question 69:

The causes of increased Gamma-glutamyl Transferase (GGT) in human serum can be due to:

(A) Alcoholism
(B) Hepatitis
(C) Pancreatitis
(D) Liver metastasis

Correct Answer: (C) (A), (C) and (D) only

View Solution

• Gamma-glutamyl Transferase (GGT) is an enzyme involved in the transfer of amino acids and peptides across the cell membrane and is a marker for liver and bile duct damage.
• (A) Alcoholism: Chronic alcohol consumption is a well-known cause of increased GGT levels due to liver damage.
• (C) Pancreatitis: GGT levels can increase due to inflammation in the pancreas, as the pancreas shares pathways with the liver.
• (D) Liver metastasis: Secondary cancer in the liver significantly raises GGT levels due to liver cell damage.
• (B) Hepatitis: While GGT can increase in hepatitis, it is not the primary marker for this condition.

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Question 70:

Human acute liver failure can be due to:

(A) Viral hepatitis
(B) Medicine
(C) Toxins
(D) Ischemia

Correct Answer: (C) (A), (B), (C) and (D)

View Solution

• (A) Viral hepatitis: A common cause of acute liver failure due to rapid liver inflamma- tion and cell damage.
• (B) Medicine: Overdose or side effects of certain medications (e.g., acetaminophen) can lead to liver failure.
• (C) Toxins: Exposure to hepatotoxic substances (e.g., aflatoxins, alcohol) can damage liver cells.
• (D) Ischemia: Lack of blood supply to the liver due to circulatory shock or thrombosis can cause acute liver failure.

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Question 71:

Read the following statements carefully:

(A) Ultracentrifugation separates molecules based on their density
(B) Gel electrophoresis separates molecules based on their mobility in an electric field
(C) Gel filtration separates molecules based on their size
(D) NMR separates molecules based on their proton signal

Choose the correct answer from the options given below:

(A) (A), (B) and (D) only
(B) (A), (B) and (C) only
(C) (A), (B), (C) and (D)
(D) (B), (C) and (D) only

Correct Answer: (B) (A), (B) and (C) only

View Solution

Ultracentrifugation separates molecules like proteins and nucleic acids based on density differences. Gel electrophoresis works on molecular mobility in an electric field. Gel filtration separates molecules by size using porous beads.

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Question 72:

One Angstrom (Å) is equal to:

(A) 0.1 nanometer
(B) 0.01 nanometer
(C) 0.001 nanometer
(D) 0.01 micrometer

Correct Answer: (A) 0.1 nanometer

View Solution

One Angstrom (1 Å) equals 10⁻¹⁰ meters, which is 0.1 nanometers. This unit is commonly used in atomic and molecular dimensions.

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Question 73:

In 1953, Frederick Sanger determined the amino acid sequence of which protein?

(A) Caspase
(B) Hemoglobin
(C) Insulin
(D) DNA polymerase

Correct Answer: (C) Insulin

View Solution

Frederick Sanger sequenced insulin, the first protein to have its amino acid sequence determined. This achievement was pivotal in the study of proteins and molecular biology.

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Question 74:

A substance that receives electrons in an oxidation-reduction reaction is called:

(A) Electron acceptor
(B) Electron donor
(C) Electron carrier
(D) Eluate

Correct Answer: (A) Electron acceptor

View Solution

In redox reactions, an electron acceptor gains electrons and becomes reduced. It plays a vital role in metabolic pathways such as respiration and photosynthesis.

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Question 75:

The substrate concentration at which an enzyme-catalyzed reaction proceeds at one-half of its velocity is called:

(A) Kcat
(B) Km
(C) V0
(D) Vmax

Correct Answer: (B) Km

View Solution

The Michaelis constant (Km) is defined as the substrate concentration at which the reaction velocity reaches half of Vmax. It reflects the enzyme’s affinity for its substrate.

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