Nokea
Where is oxygen exchanged between blood and tissues?
- A. capillaries
- B. veins
- C. ventricles
- D. arteries
Correct Answer: A
Rationale: Oxygen is exchanged between blood and tissues primarily at the capillaries. Capillaries are the smallest blood vessels where the exchange of oxygen, nutrients, and waste products occurs between the blood and the tissues. This exchange process is crucial for delivering oxygen to the body's cells and eliminating carbon dioxide waste. Veins carry blood back to the heart, arteries carry blood away from the heart, and ventricles are the lower chambers of the heart responsible for pumping blood. Therefore, capillaries are the correct answer for where oxygen is exchanged between blood and tissues.
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Which of the following describes a situation in which research results are consistent with every subsequent experiment, but the test used in the experiment does not measure what it claims to measure?
- A. reliable, but not valid
- B. valid, but not reliable
- C. neither reliable nor valid
- D. both reliable and valid
Correct Answer: A
Rationale: The correct answer is A, 'reliable, but not valid.' In this scenario, the research results are consistent in every subsequent experiment, indicating reliability. However, the test used does not measure what it claims to measure, leading to a lack of validity in the results. Choice B, 'valid, but not reliable,' would imply that the test consistently measures what it claims but the results are not consistent, which is not the case here. Choice C, 'neither reliable nor valid,' would suggest that the results are neither consistent nor relevant, which does not align with the provided scenario. Choice D, 'both reliable and valid,' would mean that the results are consistent and measure what they claim to measure, which contradicts the situation described in the question.
Which of the following choices would contain the code for making a protein?
- A. mRNA
- B. tRNA
- C. rRNA
- D. DNA polymerase
Correct Answer: A
Rationale: The correct answer is A: mRNA (messenger RNA). mRNA contains the genetic code or instructions for making a protein. During protein synthesis, mRNA carries the genetic information from DNA in the cell nucleus to the ribosomes, where proteins are synthesized. The sequence of nucleotides in mRNA corresponds to the sequence of amino acids that will be used to build the protein. Choice B, tRNA (transfer RNA), is involved in carrying amino acids to the ribosome during protein synthesis but does not contain the code for making a protein. Choice C, rRNA (ribosomal RNA), is a component of ribosomes where protein synthesis occurs but does not contain the specific code for making a protein. Choice D, DNA polymerase, is an enzyme involved in DNA replication, not in directly coding for protein synthesis.
The above experimental design description is an example of which of the following types of experiments?
- A. field experiment
- B. natural experiment
- C. controlled experiment
- D. observational study
Correct Answer: C
Rationale: The above experimental design description involves the manipulation of an independent variable (light exposure) to observe its effects on the dependent variable (plant growth) under controlled conditions. In a controlled experiment, researchers actively manipulate one or more variables while keeping all other variables constant to establish cause-and-effect relationships.
Choice A, a field experiment, typically takes place in a real-world setting but still involves manipulation and control of variables. Choice B, a natural experiment, involves observing naturally occurring differences in variables without researcher intervention. Choice D, an observational study, does not involve manipulation of variables, making it different from the described experimental design.
Which of the following is NOT a function of the liver?
- A. nutrient processing
- B. blood filtration and detoxification
- C. cholesterol and lipoprotein production
- D. insulin production and blood sugar regulation
Correct Answer: D
Rationale: The correct answer is D. The liver does not produce insulin; instead, insulin is produced by the pancreas. The liver plays a crucial role in regulating blood sugar levels by storing and releasing glucose but does not directly produce insulin. Choices A, B, and C are functions of the liver. Nutrient processing, blood filtration, detoxification, cholesterol, and lipoprotein production are essential roles performed by the liver to maintain overall metabolic balance and health.
Which of the following is a true statement about dominance in genetics?
- A. All genes adhere to Mendel's law of dominance.
- B. A dominant allele will always be expressed.
- C. When two dominant alleles are present, the resulting phenotype will express both traits.
- D. There are three or more alleles possible for all genes.
Correct Answer: B
Rationale: In genetics, dominance refers to the relationship between two different alleles of a gene where one allele (dominant) masks the expression of another allele (recessive) in an individual's phenotype. The correct statement about dominance is that a dominant allele will always be expressed in the phenotype, even in the presence of a recessive allele. This means that if an individual has at least one dominant allele for a particular trait, that trait will be expressed. Choice A is incorrect because not all genes follow Mendel's law of dominance; exceptions do exist. Choice C is incorrect because when two dominant alleles are present, only one will be expressed due to complete dominance. Choice D is incorrect as there can be more than three alleles for a gene, and not all genes have three or more alleles.