ATI TEAS 7
TEAS 7 practice test free science
1. Parkinson's disease is a neurodegenerative disorder affecting which neurotransmitter?
- A. Dopamine
- B. Acetylcholine
- C. Serotonin
- D. Glutamate
Correct answer: A
Rationale: Parkinson's disease is primarily caused by the loss of dopamine-producing neurons in the brain. Dopamine is a neurotransmitter that plays a crucial role in coordinating movement. The reduction of dopamine levels leads to the characteristic motor symptoms of Parkinson's disease, such as tremors, rigidity, and bradykinesia. Choice B, acetylcholine, is involved in functions like muscle contraction and autonomic nervous system regulation but is not primarily affected in Parkinson's disease. Serotonin (Choice C) is involved in mood regulation and sleep, not the main neurotransmitter affected in Parkinson's disease. Glutamate (Choice D) is the major excitatory neurotransmitter in the central nervous system and is not primarily implicated in Parkinson's disease pathophysiology.
2. When an atom gains or loses electrons, it becomes a(n):
- A. Molecule
- B. Isotope
- C. Ion
- D. Compound
Correct answer: C
Rationale: When an atom gains or loses electrons, it becomes an ion. Gaining or losing electrons alters the atom's electron count and charge, creating a positively or negatively charged ion. A molecule is formed when two or more atoms are chemically bonded. An isotope is a variation of an element with a different number of neutrons. A compound consists of two or more different elements chemically bonded together.
3. How do hydrogen bonds in water affect its characteristics?
- A. Hydrogen bonds are not polar enough to attract non-polar molecules.
- B. Hydrogen bonds cause water to be less dense when it is a solid than when it is a liquid.
- C. Hydrogen bonds cause water to have high surface tension, allowing some organisms to move across it.
- D. Hydrogen bonds cause water to be a good solvent.
Correct answer: C
Rationale: Hydrogen bonds in water contribute to its high surface tension, enabling some organisms to move across the water's surface. This property is essential for certain insects and small animals that rely on surface tension to move or stay afloat on water. Choice A is incorrect because hydrogen bonds are polar and can attract polar and other charged molecules. Choice B is incorrect as hydrogen bonds make ice less dense than liquid water, which is a unique property. Choice D is incorrect as the ability of water to act as a good solvent is primarily due to its polarity, not just hydrogen bonding.
4. The innate immune system provides a non-specific first line of defense. What are some physical barriers that contribute to the innate immune system?
- A. Antibodies
- B. Phagocytes
- C. Skin and mucous membranes
- D. Memory B cells
Correct answer: C
Rationale: Physical barriers such as the skin and mucous membranes are crucial components of the innate immune system's first line of defense. These barriers act as physical obstacles that prevent pathogens from entering the body. Antibodies (option A) are produced by the adaptive immune system in response to specific pathogens and do not serve as physical barriers. Phagocytes (option B) are cells that engulf and digest pathogens, playing a role in the innate immune response but not as physical barriers. Memory B cells (option D) are part of the adaptive immune system and aid in mounting a faster and more effective immune response upon subsequent exposure to a specific pathogen, but they are not physical barriers against initial pathogen entry.
5. Which statement most accurately compares and contrasts the structures of DNA and RNA?
- A. Both DNA and RNA have 4 nucleotide bases. Three of the bases are the same, but the fourth base is thymine in DNA and uracil in RNA.
- B. Both DNA and RNA have the same 4 nucleotide bases. However, the nucleotides bond differently in DNA compared to RNA.
- C. Both DNA and RNA have different numbers of nucleotide bases. DNA is a double helix while RNA is a single strand.
- D. Both DNA and RNA have a double helix structure. However, DNA contains 6 nucleotide bases and RNA contains 4 nucleotide bases.
Correct answer: A
Rationale: The correct answer is A because DNA and RNA both consist of 4 nucleotide bases, namely adenine, cytosine, and guanine, which are common in both. The key difference lies in the fourth base, which is thymine in DNA and uracil in RNA. This distinction is fundamental in understanding the structural variances between DNA and RNA. Choice B is incorrect as it incorrectly states that the nucleotides bond differently in DNA compared to RNA without specifying the crucial base differences. Choice C is inaccurate as it misrepresents the numbers of nucleotide bases in DNA and RNA, and incorrectly describes DNA as a double helix and RNA as a single strand, which is not related to the difference in bases. Choice D is incorrect as it inaccurately portrays DNA with 6 nucleotide bases and RNA with 4, which is not true; both DNA and RNA have 4 nucleotide bases, but with differences in one of the bases.
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