which enzyme digests fiber in the large intestine

ATI RN

Proctored Nutrition ATI

1. Which enzyme digests fiber in the large intestine?

A. salivary amylase
B. pancreatic amylase
C. cellulase
D. none of the above

Correct answer: D

Rationale: The correct answer is 'none of the above.' Human digestive enzymes like salivary amylase and pancreatic amylase cannot digest fiber. Instead, fiber is fermented by gut bacteria in the large intestine. Cellulase, which is an enzyme produced by some animals and microorganisms, can break down cellulose found in plants, but it is not a human digestive enzyme, making it an incorrect choice in this context.

2. Where does carbohydrate digestion begin?

A. Mouth
B. Esophagus
C. Stomach
D. Small intestine

Correct answer: A

Rationale: Carbohydrate digestion begins in the mouth. The enzyme amylase, found in saliva, starts the process by breaking down starches into sugars. The esophagus is a passageway for food to reach the stomach and does not participate in digestion. The stomach mainly digests proteins and is not the primary site for carbohydrate breakdown. While the small intestine does play a crucial role in digesting carbohydrates, it is not where the process initiates. Therefore, the correct answer is the mouth.

3. Medication for treating high blood cholesterol levels should not be used for most people unless:

A. The patient has at least three major risk factors for coronary heart disease
B. The patient has been experiencing symptoms of coronary heart disease for at least three months
C. The patient's medical insurance covers prescription drugs
D. Treatment with Therapeutic Lifestyle Changes (TLC) alone is unsuccessful after three months

Correct answer: D

Rationale: The correct answer is choice D because medication for high cholesterol is typically not considered unless Therapeutic Lifestyle Changes (TLC), which include diet and exercise, have not proven effective after a three-month period. This approach ensures that lifestyle modifications are given a fair chance to lower cholesterol levels before resorting to medication. Choice A is incorrect because the number of risk factors for coronary heart disease does not dictate when to begin medication; it is about the effectiveness of lifestyle changes. Choice B is incorrect as the duration of coronary heart disease symptoms does not determine when to start medication; the focus is on the response to TLC. Choice C is incorrect because the coverage of prescription drugs by the patient's insurance does not influence the medical decision to use medication for high cholesterol; it is based on medical necessity and effectiveness of prior interventions.

4. Each statement regarding the correlation between vitamin D and sun exposure is accurate, except one. Which is the exception?

A. The body can produce sufficient amounts of vitamin D from sunlight.
B. UV radiation can convert a precursor of vitamin D to vitamin D3 by penetrating uncovered skin.
C. Sunscreen blocks the formation of vitamin D3.
D. By the age of 70 years, the skin generally produces vitamin D at only half the level it did at the age of 20 years.

Correct answer: C

Rationale: While UV radiation can penetrate uncovered skin and convert a precursor of vitamin D to vitamin D3, sunscreen does block the formation of vitamin D3. Sunscreen is recommended by dermatologists to prevent sunburn and reduce the risk of skin cancer. The other choices are correct: the body can produce sufficient vitamin D from sunlight, UV radiation can convert a precursor of vitamin D to vitamin D3, and skin generally produces less vitamin D as a person ages.

5. What characterizes Obsessive Compulsive Disorder?

A. Uncontrollable impulse to perform an act or ritual repeatedly
B. Persistent thoughts and behavior
C. Recurring unwanted and disturbing thoughts
D. Pathological persistence of unwilled thoughts

Correct answer: A

Rationale: Obsessive Compulsive Disorder (OCD) is characterized by the uncontrollable impulse to perform an act or ritual repeatedly (Choice A). This is driven by recurring unwanted and disturbing thoughts (Choice C), but the distinguishing factor is the compulsive behavior, making choice A the most accurate. While choice B can be seen as true, it lacks the specific detail of the compulsive behavior that makes A a better answer. Choice D is not incorrect, but it uses terminology that is less precise and less commonly used to describe OCD, making it a less accurate choice than A. The provided rationale is not relevant to the question.