two mice are both heterozygous for two traits white fur ww and short fur ss their offspring are most likely to have which of the following genotypes f

ATI TEAS 7

TEAS 7 Science Practice Test

1. Two mice are both heterozygous for two traits: white fur (Ww) and short fur (Ss). Their offspring are most likely to have which of the following genotypes for these traits?

A. wwss
B. WWSS
C. WwSs
D. WWSs

Correct answer: C

Rationale: When two mice that are heterozygous for white fur (Ww) and short fur (Ss) mate, they can produce offspring with different combinations of the two traits. The Punnett square for this cross shows that the most likely genotype for the offspring is WwSs. In this case, each offspring receives one allele for white fur (W) and one for short fur (S) from each parent, resulting in a heterozygous genotype for both traits. Choice A (wwss) is incorrect as it represents a homozygous recessive genotype for both traits. Choice B (WWSS) is also incorrect as it represents a homozygous dominant genotype for both traits. Choice D (WWSs) is incorrect as it represents a genotype where one trait is homozygous dominant (W) and the other is heterozygous (S), which is not the most likely outcome based on the given parental genotypes.

2. Which vitamin is synthesized in the skin upon exposure to sunlight?

A. Vitamin A
B. Vitamin C
C. Vitamin D
D. Vitamin E

Correct answer: C

Rationale: Vitamin D is synthesized in the skin upon exposure to sunlight. When the skin is exposed to sunlight, a form of cholesterol in the skin is converted into vitamin D3 (cholecalciferol) through a series of chemical reactions. Vitamin D plays a crucial role in calcium absorption and bone health. Choice A, Vitamin A, is not synthesized in the skin upon exposure to sunlight; it is obtained through dietary sources. Choice B, Vitamin C, is not synthesized in the skin upon exposure to sunlight either. Vitamin C is obtained through dietary sources like fruits and vegetables. Choice D, Vitamin E, is not synthesized in the skin upon exposure to sunlight. Vitamin E is a fat-soluble vitamin that acts as an antioxidant and is obtained through dietary sources like nuts, seeds, and vegetable oils.

3. What is the most common cause of hospital-acquired infections (HAIs)?

A. Viruses
B. Bacteria
C. Fungi
D. Parasites

Correct answer: B

Rationale: Hospital-acquired infections (HAIs), also known as nosocomial infections, are infections that patients acquire during the course of receiving treatment in a healthcare facility. Among the options provided, bacteria are the most common cause of HAIs. Bacteria such as Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa are known to cause a wide range of infections in healthcare settings. While viruses, fungi, and parasites can also cause HAIs, bacteria are the most prevalent and significant pathogens responsible for these infections. Proper infection control measures, including hand hygiene, environmental cleaning, and antimicrobial stewardship, are essential in preventing and controlling HAIs caused by bacteria.

4. What property of a substance remains constant regardless of changes in gravity?

A. Mass
B. Weight
C. Volume
D. Density

Correct answer: A

Rationale: Mass is a measure of the amount of matter in an object and remains constant regardless of changes in gravity. Weight, on the other hand, is a measure of the gravitational force acting on an object and varies with changes in gravity. Volume is the amount of space occupied by an object and can change with changes in gravity. Density is the mass of a substance per unit volume and can also change with changes in gravity if the volume changes. Therefore, the correct answer is mass as it remains the same regardless of the gravitational force acting on the object, making it an intrinsic property of the substance.

5. What does the P-wave in an ECG correspond to?

A. Atrial repolarization
B. Depolarization of SA node
C. Ventricular depolarization
D. Ventricular repolarization

Correct answer: B

Rationale: The P-wave in an ECG represents the depolarization of the SA node and the atria, not atrial repolarization. Choice C, ventricular depolarization, is incorrect because the P-wave does not correspond to ventricular activity. Choice D, ventricular repolarization, is also incorrect as the P-wave does not depict ventricular repolarization. The correct interpretation is that the P-wave signifies the initiation of the electrical impulse at the SA node and subsequent atrial depolarization, making option B the correct answer.