Nokea
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.
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What describes a cell's reaction to being placed in a hypertonic solution?
- A. The cell will shrink as water is pulled out of the cell to equalize the concentrations inside and outside of the cell.
- B. The cell will swell as water is pulled into the cell to equalize the concentrations inside and outside of the cell.
- C. The cell will remain the same size since the concentrations inside and outside the cell are equal to begin with.
- D. The pH inside the cell will drop in order to equalize the pH inside and outside the cell.
Correct Answer: A
Rationale: A cell placed in a hypertonic solution has a higher solute concentration outside the cell compared to inside. This creates a concentration gradient that causes water to move out of the cell through osmosis to equalize the concentrations on both sides. As a result, the cell will shrink or undergo plasmolysis, as water is pulled out of the cell. Choice B is incorrect because a hypertonic solution causes water to move out of the cell, leading to shrinkage rather than swelling. Choice C is incorrect as a hypertonic solution results in a concentration gradient that leads to water leaving the cell, causing it to shrink. Choice D is incorrect because pH is not directly affected by being placed in a hypertonic solution; the change in solute concentration primarily impacts water movement.
What is the function of fascia in muscle tissue?
- A. to enclose, protect, support, and separate muscle tissue
- B. to connect muscle tissue to bone
- C. to serve as the contractile unit of muscle
- D. to slide past the actin protein cells in muscle to create contraction
Correct Answer: A
Rationale: The correct answer is A: 'to enclose, protect, support, and separate muscle tissue.' Fascia is a connective tissue that surrounds muscles, providing structural support, protecting them from friction and injury, and helping in movement. Choice B is incorrect as tendons are responsible for connecting muscle tissue to bone. Choice C is incorrect as the contractile unit of muscle is the sarcomere, not fascia. Choice D is incorrect as the process described relates to muscle contraction mechanisms involving actin and myosin, not the function of fascia.
Which of the following is an example of adaptive immunity?
- A. Inflammation
- B. Fever
- C. Antibodies
- D. Phagocytosis
Correct Answer: C
Rationale: Antibodies are produced by the adaptive immune system in response to specific antigens. They play a crucial role in targeting and neutralizing pathogens, providing long-lasting immunity against future infections. In contrast, options A (inflammation), B (fever), and D (phagocytosis) are examples of innate immunity, the body's immediate, non-specific defense mechanisms. Inflammation is a response to tissue damage, fever is a systemic response to infection, and phagocytosis is a process where cells engulf and digest pathogens, all part of the innate immune response.
Which of the following distinguishes the isotopes of an element?
- A. Isotopes are atoms of the same element that have different ionic charges.
- B. Isotopes are atoms of elements within the same group on the periodic table.
- C. Isotopes are atoms of the same element that have different numbers of neutrons.
- D. Isotopes are atoms of the same element with different electron configurations.
Correct Answer: C
Rationale: Isotopes are defined as atoms of the same element that have the same number of protons in their nucleus but different numbers of neutrons. This leads to variations in atomic mass for isotopes of an element. The different number of neutrons in isotopes results in differences in their atomic mass and properties while still belonging to the same element. Choice A is incorrect because isotopes do not have different ionic charges, they have the same chemical properties. Choice B is incorrect because isotopes are not atoms of elements within the same group on the periodic table; they are variants of the same element. Choice D is incorrect because isotopes of an element have the same electron configuration, differing only in the number of neutrons in the nucleus.
Which of the following basic mechanisms of evolution is described as the process where organisms with an advantageous trait survive more often and produce more offspring than organisms without the advantageous trait?
- A. gene flow
- B. genetic drift
- C. mutation
- D. natural selection
Correct Answer: D
Rationale: Natural selection is the basic mechanism of evolution that explains how organisms with advantageous traits are more likely to survive and reproduce in a given environment. This leads to the passing on of these favorable traits to their offspring, causing these traits to become more common in the population over time, resulting in evolutionary change. Natural selection is driven by environmental pressures that support the survival and reproduction of individuals with specific traits. Gene flow refers to the movement of genes between populations, genetic drift is the change in allele frequencies due to random events, and mutation is the source of genetic variation but is not the process by which advantageous traits become more prevalent in a population.