What is a major function of glucose?

Correct Answer: A

Rationale: Glucose serves as a primary source of energy for the body, especially for the brain and muscles. Choice B is incorrect because glucose itself is not responsible for transporting oxygen to cells. Choice C is incorrect as glucose is converted to glycogen, not the other way around. Choice D is incorrect as glucose itself does not play a direct role in maintaining body weight.

Correct Answer: B

Rationale: In a low-carbohydrate diet, fats become the primary source of calories as carbohydrate intake is restricted. Proteins can contribute to caloric intake but are not the primary source in a low-carbohydrate diet. Carbohydrates are intentionally limited in this diet, so they do not supply most of the calories. Vitamins are essential nutrients but do not provide calories.

Correct Answer: C

Rationale: The correct answer is C: Protein synthesis. This process involves the formation of proteins from amino acids to support various body functions. Gluconeogenesis (choice A) is the synthesis of glucose from non-carbohydrate sources, not protein synthesis. Deamination (choice B) is the removal of an amino group from an amino acid, not the synthesis of proteins. Transamination (choice D) is the transfer of an amino group from one molecule to another, not the direct synthesis of proteins.

Correct Answer: B

Rationale: The correct answer is B: nonessential amino acids. Nonessential amino acids can be synthesized by the body, so they do not need to be obtained through the diet. Essential amino acids, choice A, must be obtained from the diet because the body cannot produce them. Choices C and D, complete and incomplete amino acids respectively, do not accurately describe the classification of amino acids based on synthesis by the body.

Correct Answer: A

Rationale: The correct answer is the amino group. Amino groups are functional groups found in amino acids, which are the building blocks of proteins. These groups contain nitrogen and are essential for the structure and function of proteins. The carboxyl group (choice B) contains carbon, oxygen, and hydrogen, while the peptide bond (choice C) is a covalent bond formed between amino acids in a protein chain. The side chain (choice D) refers to the unique chemical structure attached to the central carbon of an amino acid and varies among different amino acids, but it does not specifically contain nitrogen.