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What is the difference between DNA and RNA?
- A. RNA has an extra Phosphate group
- B. DNA has one less oxygen than RNA
- C. RNA has one less oxygen than DNA
- D. DNA has an extra sugar molecule
Correct Answer: B
Rationale: The correct answer is B. DNA has one less oxygen atom in its sugar molecule (deoxyribose) compared to RNA, which has a ribose sugar. Choice A is incorrect because RNA does not have an extra phosphate group. Choice C is incorrect as RNA actually has one more oxygen atom than DNA. Choice D is incorrect as DNA and RNA have different sugar molecules, with DNA having deoxyribose and RNA having ribose.
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Which of the following is not found in a prokaryotic cell?
- A. Plasma membrane
- B. Cytoplasm
- C. Nucleus
- D. Ribosomes
Correct Answer: C
Rationale: The correct answer is C, 'Nucleus.' Prokaryotic cells do not have a defined nucleus, unlike eukaryotic cells. The plasma membrane, cytoplasm, and ribosomes are all components found in prokaryotic cells. The plasma membrane surrounds the cell and regulates what enters and exits, the cytoplasm is the gel-like substance that fills the cell, and ribosomes are responsible for protein synthesis.
Why does ice have the capability of floating on water?
- A. It has a higher viscosity
- B. It has a different chemical composition
- C. It has a high specific heat
- D. It forms a lattice when freezing
Correct Answer: D
Rationale: The correct answer is D. Ice forms a lattice structure when it freezes, which makes it less dense than liquid water, allowing it to float. Choice A is incorrect because viscosity refers to a fluid's resistance to flow and is not related to ice floating. Choice B is incorrect as ice and liquid water have the same chemical composition (H2O). Choice C is incorrect because the high specific heat of water is not the reason why ice floats.
Which of the following is not true of mitosis?
- A. Mitosis produces daughter cells
- B. Mitosis has five main stages
- C. Mitosis can only be done by haploids
- D. Following mitosis, daughter cells are identical to parent cells
Correct Answer: C
Rationale: The correct answer is C. Mitosis occurs in diploid cells and involves stages that result in the production of two identical daughter cells. Haploids do not undergo mitosis, as mitosis is a process specific to diploid cells. Choice A is true as mitosis does produce daughter cells. Choice B is incorrect as mitosis typically consists of four main stages: prophase, metaphase, anaphase, and telophase. Choice D is true, as one of the main outcomes of mitosis is the production of daughter cells that are genetically identical to the parent cell.
What is the difference between saturated and unsaturated fatty acids?
- A. There is no difference between saturated and unsaturated fatty acids.
- B. Saturated fatty acids contain double bonds, unlike unsaturated fatty acids.
- C. Saturated fatty acids often contain two or more pairs of double bonds, unlike unsaturated fatty acids.
- D. Saturated fatty acids contain no double bonds, unlike unsaturated fatty acids.
Correct Answer: D
Rationale: The correct answer is D. Saturated fatty acids contain no double bonds between the carbon atoms in their hydrocarbon chains, making them more solid at room temperature. Choice A is incorrect because there is a significant difference between saturated and unsaturated fatty acids. Choice B is incorrect as it inaccurately states that saturated fatty acids contain double bonds, which is a property of unsaturated fatty acids. Choice C is also incorrect as saturated fatty acids do not contain double bonds, let alone two or more pairs of double bonds.
Binary fission is a type of asexual reproduction. Which of the following occurs during the binary fission process?
- A. The chromosomes bind to the plasma membrane
- B. The chromosomes attach to the spindle formed along the axis
- C. The chromosomes gather in the center of the cell
- D. The chromosomes begin to separate
Correct Answer: A
Rationale: The correct answer is A. In binary fission, the chromosomes bind to the plasma membrane before the cell splits into two. This initial step ensures that each daughter cell receives a complete set of genetic material. Choice B is incorrect because the spindle apparatus is characteristic of eukaryotic cell division (mitosis), not prokaryotic binary fission. Choice C is incorrect as chromosomes do not necessarily gather in the center of the cell during binary fission. Choice D is incorrect because the chromosomes do not begin to separate in binary fission; they replicate and then move to opposite ends of the cell before division.