ATI TEAS 7
ATI TEAS 7 science review
1. Which state of matter has particles that are highly organized in a fixed pattern and vibrate in place?
- A. Solid
- B. Liquid
- C. Gas
- D. Plasma
Correct answer: A
Rationale: The correct answer is 'Solid.' Solids have particles that are tightly packed together in a fixed pattern, allowing them to vibrate in place. This highly organized structure gives solids a definite shape and volume. In contrast, liquids have particles that are close together but can move past each other, enabling them to flow and take the shape of their container. Gases have particles that are far apart and move freely in all directions, filling the entire space available to them. Plasmas, on the other hand, have highly energized particles that do not have a fixed pattern and are not confined by a definite volume or shape.
2. What is the primary function of the myelin sheath that surrounds some axons in the nervous system?
- A. To initiate nerve impulses
- B. To transmit sensory information
- C. To speed up the transmission of nerve impulses
- D. To connect neurons at synapses
Correct answer: C
Rationale: The primary function of the myelin sheath is to speed up the transmission of nerve impulses. The myelin sheath acts as an insulating layer around the axon, allowing for faster conduction of electrical impulses along the nerve fiber. This insulation prevents the electrical signal from dissipating or 'leaking' out, which helps in the rapid and efficient transmission of nerve impulses along the axon. Choice A is incorrect because the myelin sheath does not initiate nerve impulses; it helps in conducting them. Choice B is incorrect as the myelin sheath's main role is not in transmitting sensory information but rather in facilitating the transmission of nerve impulses. Choice D is incorrect because the myelin sheath's function is not to connect neurons at synapses; instead, it is primarily involved in enhancing the speed of nerve impulse transmission.
3. What does half-life refer to?
- A. Radioactive intensity to completely disappear
- B. The number of neutrons in a nucleus to double
- C. The number of protons in a nucleus to change
- D. An isotope to decay by half of its initial quantity
Correct answer: D
Rationale: Half-life refers to the time it takes for half of the radioactive atoms in a sample to decay. This means that after one half-life, half of the initial quantity of the radioactive substance will have decayed. Choice A is incorrect because radioactive intensity doesn't completely disappear during half-life. Choice B is incorrect as half-life doesn't refer to the number of neutrons doubling. Choice C is incorrect as half-life doesn't relate to the number of protons changing.
4. What is the difference between a homozygous recessive genotype and a homozygous dominant genotype?
- A. Both have the same phenotype, but different genotypes.
- B. Both have the same genotype, but different phenotypes.
- C. Homozygous recessive has two dominant alleles, while homozygous dominant has two recessive alleles.
- D. Homozygous recessive has two identical recessive alleles, while homozygous dominant has two identical dominant alleles.
Correct answer: D
Rationale: - Homozygous recessive genotype refers to an individual having two identical recessive alleles for a particular gene (e.g., rr for a trait where r represents the recessive allele). - Homozygous dominant genotype refers to an individual having two identical dominant alleles for a particular gene (e.g., RR for a trait where R represents the dominant allele). - The difference between the two genotypes lies in the specific alleles present in each case, with homozygous recessive having two recessive alleles and homozygous dominant having two dominant alleles. - This genetic difference results in different phenotypes being expressed, as the dominant allele typically masks the expression of the recessive allele in heterozygous individuals.
5. Why do emerging infectious diseases (EIDs) pose a significant public health threat?
- A. Because they are well-understood by medical professionals
- B. Because they are easily treatable with existing antibiotics
- C. Because they are new, rapidly evolving, and can spread quickly
- D. Because they primarily affect animals and not humans
Correct answer: C
Rationale: Emerging infectious diseases (EIDs) are a significant public health threat because they are characterized by being new or newly identified diseases that are rapidly evolving. These diseases can spread quickly within populations due to factors such as globalization, travel, urbanization, and changes in climate. EIDs often present challenges to medical professionals as they may not be well-understood initially, making it difficult to develop effective treatments or preventive measures. While some EIDs can be treatable with existing antibiotics, the rapid evolution of these diseases can lead to the development of drug resistance, further complicating treatment efforts. Additionally, EIDs are not limited to affecting animals; they can also have serious implications for human health and well-being. Therefore, the correct answer is that EIDs pose a threat because they are new, rapidly evolving, and can spread quickly. Choices A, B, and D are incorrect because EIDs are not well-understood initially, may develop drug resistance, and can affect humans significantly, not just animals.
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