Nokea
How many chromosomes do sperm and egg produce in meiosis?
- A. 23
- B. 46
- C. 25
- D. 50
Correct Answer: A
Rationale: During meiosis, sperm and egg cells produce half the number of chromosomes found in somatic cells. Each contributes 23 chromosomes, which combine to form a zygote with a total of 46 chromosomes. Choice B (46) is incorrect because this is the number of chromosomes produced in mitosis, not meiosis. Choices C (25) and D (50) are also incorrect as they do not align with the chromosome count in sex cells during meiosis.
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Where is the genetic code for each person stored?
- A. RNA
- B. DNA
- C. Nucleus
- D. Chromosomes
Correct Answer: B
Rationale: The genetic code for each person is stored in DNA. DNA carries all the hereditary information, including unique traits and characteristics. RNA (Choice A) is involved in protein synthesis but does not hold the complete genetic code. The nucleus (Choice C) is a cellular organelle that houses the DNA, but it is not the genetic code itself. Chromosomes (Choice D) are structures made of DNA and proteins, but the genetic code is specifically encoded in the DNA molecule.
Where is the genetic information of a eukaryotic cell stored?
- A. Mitochondria
- B. Nucleus
- C. Golgi Apparatus
- D. Cytoplasm
Correct Answer: B
Rationale: The correct answer is B: Nucleus. In eukaryotic cells, genetic information (DNA) is stored in the nucleus. This organelle acts as the control center of the cell, housing the DNA and regulating gene expression. Choices A, C, and D are incorrect because the genetic information is not stored in the mitochondria, Golgi Apparatus, or cytoplasm. The mitochondria are responsible for energy production, the Golgi Apparatus is involved in protein processing and packaging, and the cytoplasm is where various cellular activities take place, but none of these organelles store the genetic information.
What cycle is the sequence of reactions by which most living cells generate energy during aerobic respiration?
- A. Calvin Cycle
- B. Krebs Cycle
- C. Photosynthesis
- D. Fermentation
Correct Answer: B
Rationale: The Krebs Cycle is the correct answer. It is a series of reactions occurring in the mitochondria and is a crucial part of aerobic respiration. The Calvin Cycle is a part of photosynthesis, not respiration, making choice A incorrect. Photosynthesis (choice C) is the process by which plants, algae, and some bacteria convert light energy into chemical energy. Fermentation (choice D) is an anaerobic process that does not require oxygen and is not the primary energy-generating pathway during aerobic respiration, so it is incorrect.
Where is the site of cellular respiration in eukaryotic cells?
- A. Nucleus
- B. Chloroplasts
- C. Mitochondria
- D. Ribosomes
Correct Answer: C
Rationale: The correct answer is C: Mitochondria. Mitochondria are often referred to as the powerhouse of the cell because they are responsible for cellular respiration in eukaryotic cells. During cellular respiration, mitochondria generate energy in the form of ATP. Choices A, B, and D are incorrect. The nucleus is the organelle that houses the cell's genetic material, chloroplasts are responsible for photosynthesis in plant cells, and ribosomes are involved in protein synthesis, not cellular respiration.
How many pairs of chromosomes do all humans have?
- A. 24 pairs
- B. 23 pairs
- C. 22 pairs
- D. 20 pairs
Correct Answer: B
Rationale: All humans have 23 pairs of chromosomes, totaling 46 chromosomes. Choice A is incorrect because humans do not have 24 pairs. Choice C is incorrect as humans have 23 pairs, not 22 pairs. Choice D is incorrect as humans have 23 pairs of chromosomes, not 20 pairs.