which is a function of the liver

ATI TEAS 7

Practice Science TEAS Test

1. What is the primary function of the liver related to digestion?

A. Produces bile
B. Stores bile
C. Converts waste ammonia into urea
D. Filters and detoxifies digestion byproducts

Correct answer: D

Rationale: The primary function of the liver related to digestion is to filter and detoxify byproducts of digestion, including toxins and metabolic waste products. While the liver does produce bile and convert waste ammonia into urea, these functions are not directly related to digestion. Storing bile is mainly done by the gallbladder, not the liver.

2. The Gram stain is a differential staining technique used to classify bacteria based on their cell wall composition. Gram-positive bacteria appear

A. Pink
B. Blue
C. Red
D. Purple

Correct answer: D

Rationale: The Gram stain is a differential staining technique that categorizes bacteria into two groups based on their cell wall composition: Gram-positive and Gram-negative. Gram-positive bacteria have a thick layer of peptidoglycan in their cell walls, which retains the crystal violet stain used in the Gram staining procedure. Consequently, Gram-positive bacteria appear purple under the microscope after staining. On the other hand, Gram-negative bacteria possess a thinner peptidoglycan layer and an outer membrane that can be penetrated by the counterstain safranin, leading them to appear pink or red. Blue is not typically used to describe the color of bacteria in a Gram stain, making it an incorrect choice.

3. What is the molarity of a solution made by dissolving 4.0 grams of NaCl into enough water to make 120 mL of solution? The atomic mass of Na is 23.0 g/mol, and Cl is 35.5 g/mol.

A. 0.34 M
B. 0.57 M
C. 0.034 M
D. 0.057 M

Correct answer: B

Rationale: To find the molarity, first calculate the moles of NaCl. Moles of NaCl = 4.0 g / (23.0 g/mol + 35.5 g/mol) = 0.068 mol. Next, use the formula for molarity: Molarity = moles of solute / liters of solution. Molarity = 0.068 mol / 0.120 L = 0.57 M. Therefore, the molarity of the solution is 0.57 M. Choice A, 0.34 M, is incorrect as it does not match the calculated molarity. Choice C, 0.034 M, is incorrect as it is a decimal point off from the correct molarity. Choice D, 0.057 M, is incorrect as it does not match the calculated molarity of 0.57 M.

4. What term describes the point where parallel rays of light converge or appear to diverge after passing through a lens or reflecting off a mirror?

A. Aperture
B. Focal length
C. Refractive index
D. Lens thickness

Correct answer: B

Rationale: The correct answer is 'Focal length.' Focal length is the term used to describe the point where parallel rays of light converge or appear to diverge after passing through a lens or reflecting off a mirror. It is a critical parameter in optics that determines the magnification and image formation in optical systems. Aperture refers to the opening through which light enters a camera or telescope, not the convergence point of light rays. Refractive index is a measure of how much light is bent, not the point where rays converge. Lens thickness is the physical dimension of a lens and does not indicate the convergence point of light rays. Therefore, 'Focal length' is the most appropriate choice in this context.

5. Abduction is defined as which of the following?

A. Movement away from the midline of the body
B. Movement that results in a decrease in the angle of a joint
C. Movement that results in an increase in the angle of a joint
D. Movement towards the midline of the body

Correct answer: A

Rationale: Abduction is defined as movement away from the midline of the body. This movement occurs in the coronal plane and is essential in various body functions such as raising the arms sideways. Choices B, C, and D describe movements that are different from abduction. Choice B refers to flexion, which decreases the angle of a joint. Choice C describes extension, which increases the angle of a joint. Choice D defines adduction, which involves movement towards the midline of the body. Therefore, the correct answer is choice A.