Nokea
How are sister chromatids distinguished from homologous chromosomes in meiosis I?
- A. Sister chromatids share the same centromere, while homologous chromosomes have different centromeres.
- B. Sister chromatids have identical DNA sequences, while homologous chromosomes have slightly different sequences due to crossing over.
- C. Sister chromatids repel each other, while homologous chromosomes attract each other during synapsis.
- D. Sister chromatids separate during anaphase I, while homologous chromosomes separate during anaphase II.
Correct Answer: B
Rationale: In meiosis I, sister chromatids are exact copies of each other, containing identical DNA sequences. On the other hand, homologous chromosomes are pairs of chromosomes, with one inherited from each parent, and they can have different versions of genes due to genetic recombination during crossing over in prophase I. Choice A is incorrect because homologous chromosomes naturally have different centromeres. Choice C is incorrect as sister chromatids and homologous chromosomes do not exhibit repulsion or attraction during synapsis. Choice D is incorrect as sister chromatids separate during anaphase II, not anaphase I, while homologous chromosomes separate during anaphase I.
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Bile, a digestive juice, is produced by which organ?
- A. Stomach
- B. Liver
- C. Pancreas
- D. Small intestine
Correct Answer: B
Rationale: Bile is a digestive juice produced by the liver. It is stored in the gallbladder and released into the small intestine to aid in the digestion and absorption of fats. The stomach (Choice A) produces gastric juices, not bile. The pancreas (Choice C) produces digestive enzymes and bicarbonate but not bile. The small intestine (Choice D) is where bile is released to aid in digestion but is not the organ that produces bile.
Which of the following is a strong acid?
- A. Acetic acid (CH₃COOH)
- B. Hydrochloric acid (HCl)
- C. Citric acid
- D. Carbonic acid (H₂CO₃)
Correct Answer: B
Rationale: Hydrochloric acid (HCl) is a strong acid because it completely ionizes in water to produce hydrogen ions, leading to a high concentration of H⺠ions in solution. This characteristic makes it a strong acid. Acetic acid (CH₃COOH), citric acid, and carbonic acid (H₂CO₃) are weak acids as they only partially ionize in water, resulting in a lower concentration of H⺠ions compared to strong acids. Therefore, hydrochloric acid is the correct choice as a strong acid.
What property of a substance measures the amount of matter per unit volume?
- A. Mass
- B. Weight
- C. Density
- D. Volume
Correct Answer: C
Rationale: Density is the property of a substance that measures the amount of matter per unit volume. It is calculated by dividing the mass of an object by its volume. Mass refers to the amount of matter in an object, weight is the force of gravity acting on an object, and volume is the amount of space an object occupies. Therefore, in this context, density is the correct answer as it specifically relates to the concentration of matter within a given volume.
A ball is thrown horizontally off a cliff. Which of the following forces is responsible for its downward motion?
- A. The force of throwing
- B. Normal force from the air
- C. Tension force from the string (if used)
- D. Gravitational force
Correct Answer: D
Rationale: The gravitational force is responsible for the downward motion of the ball. When the ball is thrown horizontally off a cliff, the only force acting on it in the vertical direction is the force of gravity, which pulls the ball downward towards the ground. The other forces mentioned (force of throwing, normal force from the air, tension force from the string) do not contribute to the ball's downward motion in this scenario. The force of throwing initiates the horizontal motion, the normal force from the air opposes the ball's motion through air resistance, and tension force from the string would only be relevant if a string were attached to the ball. Therefore, gravitational force is the primary force responsible for the ball's downward motion in this situation.
What is the process by which lighter nuclei fuse to form heavier nuclei, releasing a large amount of energy?
- A. Fission
- B. Fusion
- C. Radioactivity
- D. Chain reaction
Correct Answer: B
Rationale: Fusion is the process by which lighter nuclei combine to form heavier nuclei, releasing a large amount of energy in the process. This process is the source of energy in stars, including our Sun. Fission, the process of splitting heavier nuclei into lighter nuclei, is not correct. Radioactivity involves the emission of particles or radiation from the nucleus of an unstable atom, which is different from fusion. A chain reaction is a self-sustaining reaction where the products of one reaction cause further reactions, which is unrelated to fusion.