Nokea
What is the term for the production of glucose from protein, lactate, or glycerol?
- A. glycolysis
- B. gluconeogenesis
- C. glycogenolysis
- D. glucogenesis
Correct Answer: B
Rationale: Gluconeogenesis is the correct term for the production of glucose from non-carbohydrate sources such as protein, lactate, or glycerol. Choice A, glycolysis, is the process of breaking down glucose into pyruvate. Choice C, glycogenolysis, is the breakdown of glycogen into glucose. Choice D, glucogenesis, is not a recognized term in biochemistry.
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Where does gluconeogenesis occur?
- A. Muscles.
- B. Pancreas.
- C. Liver.
- D. Spleen.
Correct Answer: C
Rationale: Gluconeogenesis mainly occurs in the liver. It is a process where glucose is synthesized from non-carbohydrate sources such as amino acids and glycerol. The liver is the primary site for gluconeogenesis due to the presence of key enzymes and substrates required for this process. Muscles do not play a significant role in gluconeogenesis, making choice A incorrect. The pancreas is involved in the regulation of blood sugar levels through insulin and glucagon but is not the primary site for gluconeogenesis, so choice B is incorrect. The spleen is not a major organ involved in glucose metabolism, making choice D incorrect.
The process of breaking down body protein into amino acids for energy is known as:
- A. Deamination.
- B. Transamination.
- C. Transcription.
- D. Catabolism.
Correct Answer: D
Rationale: The correct answer is D: Catabolism. Catabolism involves the breakdown of body proteins into amino acids to be used as energy when there is an inadequate dietary intake. Choices A and B, deamination and transamination, involve the removal and transfer of amino groups, respectively, but not the breakdown of body proteins. Choice C, transcription, is a process in genetics where DNA is used to create mRNA, not related to breaking down body proteins.
Which component of protein contains nitrogen?
- A. Amino group
- B. Carboxyl group
- C. Peptide bond
- D. Side chain
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.
What is the function of chylomicrons?
- A. Produced in the hepatic system.
- B. Composed of triglycerides and cholesterol only.
- C. Absorbed in the large intestine.
- D. Cleared from the blood by lipoprotein lipase.
Correct Answer: D
Rationale: Chylomicrons are particles that transport dietary fats from the small intestine to cells in the body. They are cleared from the bloodstream by lipoprotein lipase, an enzyme that breaks down triglycerides in chylomicrons into fatty acids and glycerol. This process allows fats to be absorbed by the body. Choices A, B, and C are incorrect because chylomicrons are not formed in the hepatic system, they are composed of various lipids including triglycerides and cholesterol, and they are absorbed in the small intestine, not the large intestine.
At what pH does the digestion of protein by pepsin in the stomach require?
- A. 1.8 and 3.5.
- B. 4.8 and 7.0.
- C. 6.8 and 8.5.
- D. 7.8 and 10.0.
Correct Answer: A
Rationale: The correct answer is A: 1.8 and 3.5. Pepsin, an enzyme involved in protein digestion, functions optimally in an acidic environment, specifically between pH 1.8 and 3.5. This low pH is necessary for pepsin to break down proteins effectively. Choices B, C, and D are incorrect because pepsin requires a highly acidic environment, ruling out the pH ranges listed in those options.