ATI TEAS 7
Chemistry
1. What is the pH of a solution with a hydrogen ion concentration of \(1 \times 10^{-9}\) M?
- A. 5
- B. 7
- C. 9
- D. 11
Correct answer: c
Rationale: The pH is calculated as the negative logarithm (base 10) of the hydrogen ion concentration. In this case, \(-\log(1 \times 10^{-9}) = 9\).
2. What is the importance of RNA splicing?
- A. Removes introns from the mRNA molecule
- B. Adds the poly-A tail to the mRNA molecule
- C. Activates the mRNA molecule for translation
- D. Modifies the structure of the protein
Correct answer: A
Rationale: Rationale: A) RNA splicing is a crucial process in gene expression where non-coding regions called introns are removed from the pre-mRNA molecule, and the remaining coding regions called exons are joined together to form the mature mRNA molecule. This process ensures that only the protein-coding sequences are retained in the mRNA for translation, allowing for the production of functional proteins. Therefore, option A is the correct answer as it accurately describes the importance of RNA splicing in generating mature mRNA molecules for protein synthesis. B) Adding the poly-A tail to the mRNA molecule is a post-transcriptional modification that occurs after RNA splicing and is not directly related to the process of removing introns. C) Activating the mRNA molecule for translation is typically achieved through the addition of a 5' cap and the poly-A tail, rather than through RNA splicing. D) Modifying the structure of the protein is not directly
3. Which of the following is the main organ responsible for regulating sleep?
- A. Thalamus
- B. Hypothalamus
- C. Pituitary gland
- D. Pineal gland
Correct answer: B
Rationale: Rationale: The hypothalamus is the main organ responsible for regulating sleep. It plays a crucial role in controlling the body's circadian rhythm, which is the internal clock that regulates the sleep-wake cycle. The hypothalamus receives input from the eyes about light and darkness, which helps in determining when it is time to sleep or wake up. It also regulates the production of melatonin by the pineal gland, which is a hormone that helps control sleep patterns. While the thalamus is involved in relaying sensory information to the brain, the pituitary gland is responsible for producing and releasing hormones, and the pineal gland produces melatonin under the control of the hypothalamus.
4. What is kwashiorkor, a protein deficiency disease, characterized by?
- A. Muscle wasting
- B. Night blindness
- C. Scurvy
- D. Rickets
Correct answer: A
Rationale: Rationale: Kwashiorkor is a type of severe acute malnutrition caused by a deficiency of dietary protein. It is characterized by symptoms such as edema (swelling due to fluid retention), skin lesions, an enlarged liver with fatty infiltrates, and muscle wasting. Muscle wasting is a key feature of kwashiorkor due to the body breaking down muscle tissue to obtain essential amino acids for vital functions. Night blindness (option B) is a symptom of vitamin A deficiency, scurvy (option C) is caused by a lack of vitamin C, and rickets (option D) is a condition resulting from a deficiency of vitamin D, calcium, or phosphate.
5. Adaptive radiation refers to the evolutionary process where:
- A. A single ancestral species diversifies into multiple descendant species due to ecological pressures in a heterogeneous environment.
- B. Two unrelated species evolve similar adaptations in response to similar environments, leading to convergent evolution.
- C. A population becomes increasingly well-adapted to its current environment through continued natural selection.
- D. The fossil record exhibits gaps or missing links in the evolutionary history of a lineage.
Correct answer: A
Rationale: Rationale: - Adaptive radiation is a process where a single ancestral species diversifies into multiple descendant species to exploit different ecological niches within a heterogeneous environment. - This diversification occurs due to the different selective pressures present in various habitats, leading to the evolution of distinct traits and adaptations in different descendant species. - Option A accurately describes the process of adaptive radiation, where the initial species undergoes rapid speciation to occupy different ecological roles and adapt to diverse environmental conditions. - Options B, C, and D do not accurately describe adaptive radiation but refer to other evolutionary processes such as convergent evolution, natural selection, and gaps in the fossil record, respectively.
6. Nervous tissue is responsible for
- A. Movement
- B. Protection
- C. Communication and coordination
- D. Nutrient transport
Correct answer: C
Rationale: Nervous tissue is responsible for communication and coordination within the body. This tissue includes neurons and supporting cells, which work together to transmit electrical signals and information throughout the body. Movement is primarily controlled by the muscular system, protection is the role of the immune system and skin, while nutrient transport is primarily handled by the circulatory system. Therefore, the correct answer is C: 'Communication and coordination.'
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