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What is the difference between a prokaryotic cell and a eukaryotic cell?
- A. Prokaryotic cells have a nucleus, while eukaryotic cells do not
- B. Eukaryotic cells have a nucleus, while prokaryotic cells do not.
- C. Prokaryotic cells have membrane-bound organelles, while eukaryotic cells do not.
- D. Eukaryotic cells have membrane-bound organelles, while prokaryotic cells do not.
Correct Answer: B
Rationale: - Prokaryotic cells are simpler and do not have a true nucleus. Their genetic material is located in the nucleoid region, which is not enclosed by a membrane.
- Eukaryotic cells are more complex and have a true nucleus that houses the genetic material, enclosed within a nuclear membrane.
- Both prokaryotic and eukaryotic cells have organelles, but eukaryotic cells have membrane-bound organelles such as mitochondria, endoplasmic reticulum, and Golgi apparatus, while prokaryotic cells lack these membrane-bound organelles.
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What happens to the potential energy of an object when it is lifted higher above the ground?
- A. Potential energy decreases
- B. Potential energy remains the same
- C. Potential energy increases
- D. Potential energy becomes zero
Correct Answer: C
Rationale: When an object is lifted higher above the ground, its potential energy increases. This is because the higher the object is lifted, the greater its potential energy due to the increased distance from the ground. The formula for gravitational potential energy is PE = mgh, where m is the mass of the object, g is the acceleration due to gravity, and h is the height above the reference point. Therefore, as the height (h) increases, the potential energy (PE) also increases, making choice C the correct answer. Choices A, B, and D are incorrect because when an object is lifted higher, it gains potential energy rather than losing it, keeping it the same, or becoming zero. Thus, the correct answer is that the potential energy of an object increases when it is lifted higher above the ground.
What is the term for the process of converting a liquid into a gas at a temperature below its boiling point?
- A. Vaporization
- B. Evaporation
- C. Condensation
- D. Sublimation
Correct Answer: B
Rationale: Evaporation is the correct term for the process of converting a liquid into a gas at a temperature below its boiling point. During evaporation, molecules of the liquid gain enough energy to escape into the gas phase, primarily occurring at the liquid's surface. Vaporization is a broader term that encompasses the conversion of a substance from a liquid or solid state to a gas, not specifically at temperatures below the boiling point. Condensation is the reverse process of evaporation, involving the conversion of a gas into a liquid. Sublimation, on the other hand, refers to the direct transition of a substance from the solid phase to the gas phase without passing through the liquid phase.
Which of the following glands is NOT directly controlled by the pituitary gland?
- A. Thyroid gland
- B. Adrenal glands
- C. Pancreas (Islets of Langerhans)
- D. Parathyroid glands
Correct Answer: C
Rationale: The pituitary gland, known as the master gland, regulates various endocrine glands by releasing specific hormones. The thyroid gland, adrenal glands, and parathyroid glands are directly controlled by the pituitary gland through hormones like thyroid-stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), and parathyroid hormone (PTH) respectively. However, the pancreas, particularly the Islets of Langerhans, is not directly influenced by the pituitary gland. The pancreas is mainly governed by blood glucose levels and hormones such as insulin and glucagon, which play a crucial role in regulating blood sugar levels and metabolism. Therefore, the correct answer is C. Choice A, the thyroid gland, is controlled by the pituitary gland through TSH. Choice B, the adrenal glands, are regulated by the pituitary gland via ACTH. Choice D, the parathyroid glands, are under the direct control of the pituitary gland through PTH.
What is the building block of RNA?
- A. Amino acid
- B. Nucleotide
- C. Protein
- D. Fatty acid
Correct Answer: B
Rationale: Nucleotide: Nucleotides are the building blocks of RNA. A nucleotide consists of a nitrogenous base (adenine, guanine, cytosine, or uracil in RNA), a sugar (ribose in RNA), and a phosphate group. A) Amino acid: Amino acids are the building blocks of proteins, not RNA. C) Protein: Proteins are made up of amino acids, not nucleotides. D) Fatty acid: Fatty acids are components of lipids, not RNA.
The pH scale is used to indicate the concentration of:
- A. Hydrogen ions
- B. Oxygen
- C. Salts
- D. Sugar molecules
Correct Answer: A
Rationale: The pH scale is a measure of the concentration of hydrogen ions in a solution, representing its acidity or basicity. A lower pH value indicates higher hydrogen ion concentration and acidity, while a higher pH value indicates lower hydrogen ion concentration and basicity. Choice A, 'Hydrogen ions,' is the correct answer because the pH scale specifically measures the concentration of hydrogen ions in a solution. Choices B, C, and D are incorrect as the pH scale is not used to indicate the concentration of oxygen, salts, or sugar molecules.