Nokea
Which of the following functional groups is present in carboxylic acids?
- A. Carbonyl
- B. Hydroxyl
- C. Carboxyl
- D. Aldehyde
Correct Answer: C
Rationale: Carboxylic acids contain the carboxyl functional group, which consists of a carbonyl group (C=O) and a hydroxyl group (-OH) attached to the same carbon atom. The carboxyl group is represented as -COOH in the molecular structure of carboxylic acids. Therefore, the correct functional group present in carboxylic acids is the carboxyl group, making option C the correct choice. Option A, 'Carbonyl,' is incorrect as it only refers to the C=O group without the -OH component present in carboxylic acids. Option B, 'Hydroxyl,' is incorrect as it only represents the -OH group without the carbonyl group. Option D, 'Aldehyde,' is incorrect as it refers to a different functional group with a carbonyl group attached to a hydrogen atom, not the carboxyl group found in carboxylic acids.
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An object is thrown upwards and reaches a maximum height. Which of the following statements is TRUE about its velocity and acceleration at the peak?
- A. Velocity is zero and acceleration is maximum upwards.
- B. Velocity is maximum and acceleration is zero.
- C. Velocity is maximum and acceleration is maximum upwards.
- D. Velocity is zero and acceleration is maximum downwards.
Correct Answer: A
Rationale: At the peak of the object's motion, its velocity is zero because it momentarily stops before changing direction and starts to fall back down. The acceleration at the peak is maximum upwards as gravity is acting against the object's motion, slowing it down until it stops momentarily. Choice A is correct because at the peak, the object's velocity is zero, and the acceleration is maximum upwards. Choice B is incorrect because the velocity is not maximum but zero at the peak. Choice C is incorrect as both velocity and acceleration are not maximum at the peak. Choice D is incorrect as the acceleration at the peak is upwards, opposing the object's motion, not downwards.
Which of the following organelles is responsible for protein production in the cell?
- A. Ribosomes
- B. Golgi apparatus
- C. Mitochondria
- D. Lysosomes
Correct Answer: A
Rationale: The correct answer is A: Ribosomes. Ribosomes are the organelles responsible for protein synthesis in the cell. They can be found either freely floating in the cytoplasm or attached to the endoplasmic reticulum. The Golgi apparatus (Choice B) is involved in processing and packaging proteins, not protein production. Mitochondria (Choice C) are responsible for energy production, not protein synthesis. Lysosomes (Choice D) are involved in digestion and waste removal, not protein production.
What is the name for the change in enthalpy (heat) associated with a chemical reaction at constant pressure?
- A. Entropy
- B. Enthalpy
- C. Gibbs free energy
- D. Heat of reaction
Correct Answer: D
Rationale: The correct answer is D, Heat of reaction. The heat of reaction, also known as the enthalpy change, is the amount of heat absorbed or released during a chemical reaction at constant pressure. Entropy (A) is a measure of the disorder or randomness of a system and is not specifically related to heat changes in a chemical reaction. Enthalpy (B) is the total heat content of a system and not just the change associated with a reaction. Gibbs free energy (C) is a measure of the energy available to do work in a system at constant temperature and pressure, but it is not the specific term for the heat change in a chemical reaction.
What is the largest lymphatic vessel in the body responsible for draining lymph from most of the body called?
- A. Jugular vein
- B. Thoracic duct
- C. Subclavian vein
- D. Aorta
Correct Answer: B
Rationale: The correct answer is B: Thoracic duct. The thoracic duct is the largest lymphatic vessel in the body and is responsible for draining lymph from most of the body. The jugular vein, subclavian vein, and aorta are not lymphatic vessels responsible for draining lymph. The jugular vein and subclavian vein are blood vessels, while the aorta is the main artery that carries oxygenated blood from the heart. Understanding the role and anatomy of the lymphatic system is crucial for comprehending the body's immune response and fluid balance.
What is the involuntary muscle tissue found in the walls of blood vessels and organs like the stomach and intestines?
- A. Skeletal muscle
- B. Cardiac muscle
- C. Smooth muscle
- D. Striated muscle
Correct Answer: C
Rationale: Smooth muscle is the correct answer. It is the involuntary muscle tissue found in the walls of blood vessels and organs like the stomach and intestines. Smooth muscle is responsible for various involuntary movements in the body, such as peristalsis in the digestive system and regulating blood flow in blood vessels. Skeletal muscle is voluntary and attached to bones for movement. Cardiac muscle is specific to the heart and not found in blood vessel walls or organs like the stomach and intestines. Striated muscle refers to both skeletal and cardiac muscle due to their striped appearance under a microscope, but it does not specifically describe the involuntary muscle tissue in the walls of blood vessels and organs as asked in the question.