at which step in the scientific method might a scientist create a model

ATI TEAS 7

ATI TEAS 7 Science

1. At which step in the scientific method might a scientist create a model?

A. Hypothesis
B. Data analysis
C. Experimentation
D. Conclusion

Correct answer: A

Rationale: In the scientific method, scientists often create models during the hypothesis stage. Creating models at this stage helps visualize or simulate ideas before proceeding to experimentation and data analysis. Models are valuable tools that allow scientists to conceptualize and test their ideas before conducting experiments to gather data and draw conclusions. Therefore, the correct answer is A. Choice B, data analysis, occurs after experiments have been conducted and data has been collected, making it an incorrect choice. Choice C, experimentation, involves conducting tests and observations based on the hypothesis, but the creation of models typically happens before this stage. Choice D, conclusion, is the final step where scientists interpret the results and draw implications, making it an inappropriate step for creating a model.

2. What is the difference between homologous chromosomes and sister chromatids?

A. Homologous chromosomes have the same genes but may have different alleles, while sister chromatids are identical copies of the same chromosome.
B. Homologous chromosomes are only found in diploid cells, while sister chromatids are found in both haploid and diploid cells.
C. Both homologous chromosomes and sister chromatids are genetically identical, but only sister chromatids separate during mitosis.
D. Both homologous chromosomes and sister chromatids can separate during mitosis, but only homologous chromosomes have different alleles.

Correct answer: A

Rationale: Rationale: - Homologous chromosomes are pairs of chromosomes that have the same genes in the same order, one from each parent. While they carry the same genes, they may have different alleles (variants of a gene). - Sister chromatids are exact copies of each other, formed during DNA replication. They are held together by a centromere and are produced during the S phase of the cell cycle. - During meiosis, homologous chromosomes pair up and exchange genetic material through crossing over, leading to genetic variation. Sister chromatids separate during mitosis to ensure each daughter cell receives an identical copy of the genetic material.

3. What is the momentum of a car with a mass of 1500 kg moving at a speed of 20 m/s?

A. 30,000 kg m/s
B. 1500 kg m/s
C. 20 kg m/s
D. Momentum cannot be determined without knowing the direction of motion.

Correct answer: A

Rationale: The momentum of an object is calculated by multiplying its mass by its velocity. In this case, the momentum of the car can be determined using the formula momentum = mass x velocity. Substituting the given values, momentum = 1500 kg x 20 m/s = 30,000 kg m/s. Therefore, the correct answer is A, 30,000 kg m/s. Choice B (1500 kg m/s) is incorrect because that value represents the mass of the car, not its momentum. Choice C (20 kg m/s) is incorrect as it only represents the speed of the car, not its momentum. Choice D (Momentum cannot be determined without knowing the direction of motion) is incorrect because momentum is a vector quantity and can be determined using magnitude and direction, but in this case, only the magnitude is required.

4. Which element shares the same group (family) on the periodic table with helium (He)?

A. Neon (Ne)
B. Boron (B)
C. Carbon (C)
D. Oxygen (O)

Correct answer: A

Rationale: Neon (Ne) shares the same group (family) on the periodic table with helium (He). Both helium and neon belong to Group 18 (Noble Gases) due to their complete and stable outer electron shells, making them chemically inert. Boron (B), Carbon (C), and Oxygen (O) are not in the same group as helium. Boron is in Group 13, Carbon is in Group 14, and Oxygen is in Group 16 on the periodic table.

5. How do DNA and RNA function together as part of the human genome?

A. DNA carries genetic information from RNA to the cell cytoplasm.
B. RNA carries genetic information from DNA to the cell cytoplasm.
C. DNA and RNA carry genetic information from the cell nucleus to the cytoplasm.
D. DNA and RNA do not interact within the cell.

Correct answer: B

Rationale: The correct answer is B. RNA acts as a messenger carrying genetic instructions from the DNA in the nucleus to the cytoplasm, where proteins are synthesized. This process is known as transcription and translation, where DNA provides the blueprint for protein synthesis, and RNA delivers this information to the cellular machinery in the cytoplasm. Choice A is incorrect as it inaccurately states that DNA carries genetic information from RNA, which is the opposite of the actual flow of information. Choice C is incorrect as it suggests that both DNA and RNA together carry genetic information from the nucleus to the cytoplasm, which is not accurate. Choice D is incorrect as DNA and RNA do interact within the cell, playing crucial roles in genetic information processing and protein synthesis.