What is the monomer for nucleic acids?
- A. Nucleotide
- B. Amino acid
- C. Phosphate group
- D. Ribosome
Correct Answer: A
Rationale: The correct answer is A: Nucleotide. Nucleotides are indeed the monomers that make up nucleic acids like DNA and RNA. They consist of a sugar molecule, a phosphate group, and a nitrogenous base. Amino acids are the monomers of proteins, not nucleic acids. While the phosphate group is a component of nucleotides, it is not the sole monomer. Ribosome is a cellular organelle involved in protein synthesis and is not a monomer for nucleic acids.
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What is the diastole cycle in the heart?
- A. Relaxation of the heart
- B. Contraction of the heart
- C. Pulse rate of the heart
- D. Blood circulation
Correct Answer: A
Rationale: The diastole cycle in the heart refers to the relaxation phase, where the heart chambers relax and fill with blood. This phase is crucial for the heart to refill and prepare for the next contraction (systole), which pumps blood out of the heart. Therefore, the correct answer is choice A, 'Relaxation of the heart.' Choices B, C, and D are incorrect in the context of cardiac physiology. Choice B, 'Contraction of the heart,' refers to systole, the phase of heart contraction. Choice C, 'Pulse rate of the heart,' is related to the number of heartbeats per minute, not the diastole cycle specifically. Choice D, 'Blood circulation,' is a broader term that encompasses the entire circulatory system rather than focusing on the heart's specific relaxation phase.
Most catalysts found in biological systems are which of the following?
- A. Special lipids called cofactors.
- B. Special proteins called enzymes.
- C. Special lipids called enzymes.
- D. Special proteins called cofactors.
Correct Answer: B
Rationale: Enzymes are special proteins that act as catalysts in biological systems. They accelerate chemical reactions by lowering the activation energy required for the reaction to occur. Enzymes play a critical role in the regulation of metabolic pathways and are essential for various biological processes. While some enzymes may require cofactors for activity, the enzymes themselves are the catalysts in biological systems. Therefore, choice B, special proteins called enzymes, is the most suitable answer. Choices A, C, and D are incorrect because enzymes, not lipids, are the primary catalysts in biological systems.
Where does the digestion of food start?
- A. Esophagus
- B. Stomach
- C. Small intestine
- D. Mouth
Correct Answer: D
Rationale: The correct answer is the mouth. Digestion begins in the mouth where mechanical breakdown occurs through chewing, and chemical breakdown begins with saliva. Enzymes in saliva start breaking down carbohydrates, initiating the digestion process. The esophagus is responsible for transporting food from the mouth to the stomach and does not play a role in the digestion process. The stomach continues the digestion process after the food leaves the mouth. The small intestine is primarily responsible for absorbing nutrients from the digested food, rather than being the initial site of digestion.
Which of the following glands is responsible for regulating the body's metabolism?
- A. Pituitary gland
- B. Thyroid gland
- C. Adrenal gland
- D. Pineal gland
Correct Answer: B
Rationale: The correct answer is B: Thyroid gland. The thyroid gland is responsible for regulating the body's metabolism by producing hormones like thyroxine. These hormones play a key role in controlling the body's metabolic rate and energy production. Choice A, the pituitary gland, is often referred to as the 'master gland' but is not primarily responsible for regulating metabolism. Choice C, the adrenal gland, is involved in producing hormones like adrenaline and cortisol, which are crucial for the body's stress response but not primarily for metabolism. Choice D, the pineal gland, is responsible for producing melatonin, which regulates sleep-wake cycles and not directly related to metabolic regulation.
Which organ's primary role is the production of bile and other metabolic functions such as blood sugar regulation and detoxification?
- A. Gallbladder
- B. Pancreas
- C. Liver
- D. Stomach
Correct Answer: C
Rationale: The correct answer is the liver. The liver is responsible for producing bile, regulating blood sugar levels, and detoxifying the blood. Bile produced by the liver is stored in the gallbladder. The pancreas primarily functions in digestion by producing enzymes and insulin, while the stomach is mainly involved in breaking down food through the secretion of gastric juices.