Nokea
Protein is constantly being exchanged between which two components?
- A. tissue and plasma.
- B. the liver and the small intestine.
- C. blood and lymph.
- D. the heart and lungs.
Correct Answer: A
Rationale: The correct answer is 'tissue and plasma.' Protein turnover involves the continuous exchange of proteins between body tissues and the bloodstream (plasma) as part of normal metabolic processes. This process ensures a balance in protein levels throughout the body. Choices B, C, and D are incorrect as they do not represent the primary sites for protein turnover in the body.
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The type of protein-energy malnutrition that results in edema, hypoalbuminemia, skin lesions, and fatty liver is:
- A. cachexia.
- B. marasmus.
- C. kwashiorkor.
- D. sarcopenia.
Correct Answer: C
Rationale: The correct answer is C, kwashiorkor. Kwashiorkor is a type of protein-energy malnutrition characterized by edema, hypoalbuminemia, skin lesions, and fatty liver. Edema is a key feature of kwashiorkor due to hypoalbuminemia, which leads to decreased oncotic pressure. Marasmus (choice B) is a form of severe malnutrition characterized by energy deficiency without significant protein deficiency, resulting in severe wasting. Cachexia (choice A) is a syndrome characterized by weight loss, muscle atrophy, fatigue, weakness, and loss of appetite in someone who is not actively trying to lose weight. Sarcopenia (choice D) is the age-related loss of muscle mass and function.
Which lipoprotein increases the risk of cardiovascular disease?
- A. Low-density lipoprotein (LDL)
- B. High-density lipoprotein (HDL)
- C. Very low-density lipoprotein (VLDL)
- D. Chylomicrons
Correct Answer: A
Rationale: The correct answer is A: Low-density lipoprotein (LDL). LDL is often referred to as 'bad cholesterol' because it can lead to plaque buildup in arteries, increasing the risk of cardiovascular disease. High-density lipoprotein (HDL) is considered 'good cholesterol' as it helps remove LDL from the arteries, reducing the risk of cardiovascular issues. Very low-density lipoprotein (VLDL) and chylomicrons are also lipoproteins that transport fats in the bloodstream, but they are not as strongly associated with an increased risk of cardiovascular disease as LDL.
Two amino acids are chemically joined by a:
- A. double bond.
- B. hydrogen bond.
- C. carboxyl bond.
- D. peptide bond.
Correct Answer: D
Rationale: The correct answer is D, peptide bond. A peptide bond is formed through a dehydration synthesis reaction between the amine group of one amino acid and the carboxyl group of another amino acid. This bond is crucial in protein synthesis. Choices A, B, and C are incorrect. A double bond involves sharing two pairs of electrons, a hydrogen bond is a weak attraction between a hydrogen atom and an electronegative atom, and a carboxyl bond is not a common term in biochemistry.
Which of the following is an example of a plasma protein?
- A. Collagen.
- B. Myosin.
- C. Albumin.
- D. Phospholipid.
Correct Answer: C
Rationale: The correct answer is C, albumin. Albumin is a plasma protein that plays a crucial role in maintaining fluid balance in the blood. Collagen (choice A) is a structural protein found in connective tissues, not a plasma protein. Myosin (choice B) is a protein involved in muscle contraction, not found in the blood plasma. Phospholipid (choice D) is a type of lipid molecule, not a protein present in plasma.
A protein that contains all the essential amino acids in the proper proportions is called:
- A. simple
- B. indispensable
- C. complete
- D. complementary
Correct Answer: C
Rationale: A complete protein is the term used to describe a protein that contains all the essential amino acids required by the body in the right proportions. This makes choice C the correct answer. Choice A, 'simple,' is incorrect as it does not reflect the concept of essential amino acids. Choice B, 'indispensable,' while related to importance, does not specifically address the presence of all essential amino acids. Choice D, 'complementary,' is also incorrect as it refers to combining proteins to achieve a complete amino acid profile, rather than describing a protein that already contains all essential amino acids.