animal cells use which of the following methods to divide

HESI A2

Biology HESI A2 Practice Test

1. How do animal cells divide?

A. Through a contractile ring
B. Via a cell plate
C. Both methods
D. None of the above

Correct answer: A

Rationale: Animal cells divide through a contractile ring made of actin and myosin filaments. The ring contracts, pinching the cell membrane in the middle to form two daughter cells. Plant cells use a cell plate due to their rigid cell walls, making choices B and C incorrect. Choice D is incorrect as animal cells do use the contractile ring method for division.

2. Which of the following is not a product of the Krebs cycle?

A. carbon dioxide
B. oxygen
C. adenosine triphosphate (ATP)
D. energy carriers

Correct answer: B

Rationale: The correct answer is B: oxygen. Oxygen is not a product of the Krebs cycle. During the Krebs cycle, carbon dioxide, adenosine triphosphate (ATP), and energy carriers like NADH and FADH2 are produced. Carbon dioxide is a byproduct of the cycle, ATP is a form of energy produced, and energy carriers play a crucial role in transferring energy within the cell. Therefore, oxygen is the only option that is not a product of the Krebs cycle, making it the correct answer.

3. How should a researcher test the hypothesis that radiation from cell phones is significant enough to raise the temperature of water in a test tube?

A. Dial a cell phone that rests beside a test tube of water, let it ring for two minutes, and record the temperature of the water before and after the two-minute interval.
B. Dial a cell phone that rests beside a test tube of water; let it ring for two, three, and four minutes; and record the temperature of the water before and after each interval.
C. Use three different brands of cell phone; dial each as it rests beside its own test tube of water, let it ring for two minutes, and record the temperature of the water before and after the two-minute interval.
D. Use three different brands of cell phone, dial each and let one ring for two minutes, one for three minutes, and one for four minutes; record the temperature of the water before and after each interval.

Correct answer: A

Rationale: To test the hypothesis that radiation from cell phones raises the temperature of water in a test tube, the most appropriate method is to dial a cell phone next to a test tube of water, let it ring for a consistent two-minute interval, and record the temperature before and after. Choice A is correct because it provides a controlled approach to isolate the impact of the phone's radiation on the water temperature. Choices B, C, and D introduce additional variables that could confound the results. Choice B varies the duration of exposure, making it difficult to attribute temperature changes specifically to the radiation. Choice C introduces the factor of different cell phone brands, which could introduce variability not related to radiation. Choice D also varies exposure times and introduces the factor of multiple phone brands, making it harder to determine the direct impact of cell phone radiation on water temperature. Therefore, choice A is the most suitable option for this experiment.

4. During which phase is the chromosome number reduced from diploid to haploid?

A. S phase
B. interphase
C. mitosis
D. meiosis I

Correct answer: D

Rationale: The correct answer is 'meiosis I.' During meiosis I, the chromosome number is reduced from diploid to haploid through two rounds of division. Choice A ('S phase') is incorrect as the S phase is part of the cell cycle where DNA is replicated. Choice B ('interphase') is also incorrect as interphase is the phase where the cell prepares for division. Choice C ('mitosis') is incorrect as mitosis is a process where a diploid cell divides to produce two identical diploid daughter cells, maintaining the chromosome number.

5. Which is true of the term Phenotype?

A. It is the genetic code
B. Phenotype determines genotype
C. Genotype determines phenotype
D. Genotype, epigenetic factors, and environmental factors determine phenotype

Correct answer: D

Rationale: The term "phenotype" refers to the observable characteristics or traits of an organism, which are determined by a combination of genotype (genetic makeup), epigenetic factors (modifications to gene expression), and environmental factors (external influences and experiences). Genotype, epigenetic factors, and environmental factors all play a role in determining an individual's phenotype, making option D the correct statement. Options A, B, and C are incorrect because the phenotype is not the genetic code, the phenotype does not determine the genotype, and it is the genotype that influences the phenotype, not the other way around.