Biomolecules

The correct option is (A) : Glucose

A polymer of glucose is cellulose. The units of -β-D(+) glucose are joined together. Through -glycosidic linkage, C₁ of one glucose unit is joined to C₄ of another.

Adrenaline hormone increases pulse rate and controls blood pressure. 

• It releases glucose from liver glycogen and fatty acids from fatsin emergencies. 
• Adrenaline is commonly known as the fight or flight hormone and is produced by the adrenal glands.
• It is produced after receiving a message from the brain that a stressful situation has presented itself.
• Adrenaline hormone helps to release fatty acids from fat and glucose from liver glycogen under the condition of stress. 

Hence, Option C) Adrenaline is the correct answer.

Answer:

Explanation:

• A peptide bond is a covalent bond formed between the carboxyl group (-COOH) of one amino acid and the amino group (-NH₂) of another.
• This bond formation involves a condensation reaction (removal of a water molecule).
• Proteins are made up of long chains of amino acids linked via these peptide bonds, forming structures called polypeptides.

Incorrect options:

• Option 1: β-glycosidic bonds link monosaccharides in carbohydrates (e.g., cellulose).
• Option 3: Dative bonds (coordinate bonds) involve a shared pair of electrons donated by one atom—less common in protein structure.
• Option 4: α-glycosidic bonds are also found in carbohydrates (e.g., starch), not in proteins.

Statement I: A unit formed by the attachment of a base to the 1' position of sugar is known as a nucleoside. This statement is true. A nucleoside is indeed formed by the attachment of a nitrogenous base (e.g., adenine, guanine, cytosine, thymine, or uracil) to the 1' carbon of a sugar molecule (ribose or deoxyribose).
Statement II: When a nucleoside is linked to phosphoric acid at the 5'-position of the sugar moiety, we get a nucleotide. This statement is false. A nucleotide is formed when a nucleoside (base attached to sugar) is linked to a phosphoric acid (phosphate) molecule at the 5' carbon of the sugar moiety. However, the statement erroneously mentions "phosphorous acid" instead of phosphoric acid, which is incorrect.

Therefore, The correct option is (B): Statement I 1s true but Statement II is false.

The correct answer is Option 4: Mg plays roles in neuromuscular function and intraneuronal transmission.

Magnesium (Mg) is an essential mineral and cofactor that plays a critical role in various biochemical reactions in the human body. It is especially important in the functioning of the nervous and muscular systems. Mg helps regulate neurotransmitter release, muscle contraction, and nerve signal transmission, making it vital for both neuromuscular function and intraneuronal communication.

Explanation of all options:

Option 1: "All enzymes that utilise ATP in phosphate transfer require Ca as the cofactor" – This statement is incorrect. Although calcium (Ca) does act as a cofactor for certain enzymes, most ATP-dependent reactions actually require magnesium (Mg) as the true cofactor. Mg stabilizes ATP molecules by binding to the phosphate groups, making it essential for enzyme catalysis involving ATP.

Option 2: "The bone in human body is an inert and unchanging substance" – This is a misconception. Bone is a living tissue that continuously undergoes remodeling. It actively participates in mineral storage, blood cell formation (hematopoiesis), and responds to mechanical and metabolic stress. Therefore, it is not inert or unchanging.

Option 3: "The daily requirement of Mg and Ca in the human body is estimated to be 0.2–0.3 g" – This statement is incorrect. The daily recommended intake for calcium in adults is around 1000–1200 mg (1–1.2 g), and for magnesium, it ranges between 300–400 mg. The combined requirement of 0.2–0.3 g is a significant underestimation.

Option 4: "Mg plays roles in neuromuscular function and interneuronal transmission" – This is the correct statement. Magnesium is vital for regulating ion channels, especially calcium and potassium, which are crucial for proper muscle contractions and nerve signal propagation. A deficiency in Mg can lead to muscle cramps, spasms, and neurological issues.

In conclusion, magnesium's crucial role in both neuromuscular and neuronal functions makes Option 3 the best and most scientifically accurate choice among the given options. Understanding the physiological significance of minerals like Mg and Ca is essential for mastering human biology, especially for competitive exams like NEET.