during which of the following stages does crossing over occur

ATI TEAS 7

TEAS Practice Test Science

1. During which of the following stages does crossing over occur?

A. Mitosis Prophase
B. Meiosis Prophase I
C. Meiosis Prophase II
D. Interphase

Correct answer: B

Rationale: Crossing over occurs during Prophase I of meiosis. This stage is specifically associated with genetic recombination, where homologous chromosomes exchange genetic material. This process contributes to genetic diversity by creating new combinations of alleles. Choices A, C, and D are incorrect. In mitosis, crossing over does not occur as it involves the separation of replicated chromosomes. Meiosis Prophase II is focused on the reformation of nuclei and does not involve crossing over. Interphase is a stage where the cell prepares for division and is not associated with crossing over.

2. What is the temperature of 35°C in Kelvin?

A. 220
B. 238
C. 308
D. 345

Correct answer: C

Rationale: To convert Celsius to Kelvin, add 273.15 to the Celsius temperature. In this case, 35°C + 273.15 = 308.15 K. Therefore, the correct answer is 308 K. Choice A (220) is incorrect as it does not account for adding 273.15 to convert to Kelvin. Choice B (238) is incorrect as it is not the result of adding 273.15 to 35°C. Choice D (345) is incorrect as it is not the correct conversion of 35°C to Kelvin.

3. What is a gene, and what is the relationship between genes, genotype, and phenotype?

A. A gene is a sequence of amino acids; genes make up proteins; genotype determines phenotype
B. A gene is a portion of DNA; genes determine traits; genotype is the genetic makeup; phenotype is the physical manifestation
C. A gene is a protein; proteins determine traits; genotype is the set of all genes
D. A gene is a lipid; lipids determine traits; phenotype is the physical manifestation

Correct answer: B

Rationale: A gene is a portion of DNA that contains the instructions for a specific trait. Genotype refers to the genetic makeup of an organism, encompassing all its genes. Phenotype, on the other hand, is the observable physical manifestation resulting from the interaction between an organism's genotype and environmental factors. Choice A is incorrect because genes do not consist of amino acids directly; they are sequences of nucleotides. Choice C is incorrect as genes do not determine traits directly but provide the instructions for proteins that may influence traits. Choice D is incorrect as genes are not lipids, and lipids do not determine traits; they are a type of biomolecule with different functions.

4. Which part of the nervous system controls the 'fight or flight' response?

A. Central nervous system
B. Peripheral nervous system
C. Autonomic nervous system
D. Sympathetic nervous system

Correct answer: D

Rationale: The correct answer is the sympathetic nervous system. It controls the 'fight or flight' response by preparing the body for stressful situations. The central nervous system (Choice A) consists of the brain and spinal cord but does not directly control the 'fight or flight' response. The peripheral nervous system (Choice B) includes nerves outside the brain and spinal cord, while the autonomic nervous system (Choice C) regulates involuntary bodily functions but is not specific to the 'fight or flight' response.

5. What is the primary function of Bartholin's glands?

A. Secretes hormones that help the body respond to stress
B. Provide lubrication for the vagina
C. Helps control growth and development of the body
D. Stimulate the development of T cells

Correct answer: B

Rationale: Bartholin's glands are two small glands located on each side of the vaginal opening. Their primary function is to secrete fluids that help lubricate the vagina during sexual arousal. This lubrication helps to reduce friction and discomfort during sexual activity, making intercourse more comfortable and pleasurable. Choices A, C, and D are incorrect because Bartholin's glands do not secrete hormones to respond to stress, control growth and development, or stimulate the development of T cells. Their main role is specifically related to vaginal lubrication.