Nokea
Where do both digestion and absorption occur in the digestive system?
- A. Stomach
- B. Esophagus
- C. Gallbladder
- D. Small intestine
Correct Answer: D
Rationale: Both digestion and absorption take place in the small intestine. The small intestine is a crucial organ where the breakdown of food into smaller molecules, digestion, occurs with the help of enzymes. This process is essential for the absorption of nutrients, where the smaller molecules are taken up by the bloodstream for distribution throughout the body. While the stomach aids in digestion through the action of gastric juices, the esophagus serves as a tube for food passage, and the gallbladder stores bile produced by the liver to aid in fat digestion. However, neither digestion nor absorption occurs in the stomach, esophagus, or gallbladder, making the small intestine the correct answer for both processes.
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What process causes most of the carbon dioxide from the blood to move into alveoli?
- A. Active transport
- B. Diffusion down a concentration gradient
- C. Passive transport using carrier proteins
- D. Conversion to carbon monoxide
Correct Answer: B
Rationale: The correct answer is B: Diffusion down a concentration gradient. In the alveoli, there is a higher concentration of carbon dioxide in the blood compared to the air, leading to the movement of carbon dioxide from the blood into the alveoli through diffusion. This natural movement occurs due to the concentration gradient, ensuring the elimination of carbon dioxide during respiration. Active transport, a process requiring energy, is not involved in this movement. Passive transport using carrier proteins is not the primary mechanism for carbon dioxide movement in the lungs. Conversion to carbon monoxide is incorrect as it does not explain the physiological process of carbon dioxide exchange in the alveoli.
Which of the following triangular areas of the human body is described as the perineum?
- A. The area between the nipples on the chest and the belly button.
- B. The area on the back between the neck and the two shoulder blades.
- C. The area that contains the orifices of the urinary, digestive, and reproductive systems.
- D. The area between the edges of the eyes and the chin.
Correct Answer: C
Rationale: The perineum is the specific triangular region in the pelvic area that houses the openings of the urinary, digestive, and reproductive systems. It is essential for supporting these vital bodily functions. The other options describe different anatomical areas that are not related to the perineum. Understanding the location and function of the perineum is crucial for healthcare professionals to provide accurate assessments and care to patients.
Why does dipping an apple slice in lemon juice prevent it from browning through an enzymatic reaction?
- A. Lemon juice has a pH that inactivates the enzymes.
- B. Lemon juice has enzymes that reverse the browning.
- C. Lemon juice functions to dilute the brown material.
- D. Lemon juice functions to bleach the brown material.
Correct Answer: A
Rationale: The correct answer is A: Lemon juice has a pH that inactivates the enzymes. Enzymatic browning in apples is caused by the enzyme polyphenol oxidase. When an apple is sliced, the enzyme comes into contact with oxygen in the air, leading to the browning process. Lemon juice contains citric acid, which lowers the pH of the apple's surface, creating an acidic environment that inactivates the polyphenol oxidase enzyme, thus preventing the browning reaction. This acidic environment denatures the enzyme, rendering it unable to catalyze the browning reaction. Therefore, by dipping the apple slice in lemon juice, the enzymatic activity that causes browning is effectively inhibited, maintaining the apple's color and freshness.
Which of the following physiological responses is caused by the release of anti-diuretic hormone?
- A. Decrease in water reabsorption in the collecting duct
- B. Decrease in the concentration of calcium in the glomerulus
- C. Increase in the concentration of calcium in the glomerulus
- D. Increase in water reabsorption in the collecting duct
Correct Answer: D
Rationale: The correct answer is D: Increase in water reabsorption in the collecting duct. Anti-diuretic hormone (ADH), also known as vasopressin, acts on the kidneys to increase water reabsorption in the collecting ducts, leading to the concentration of urine and conservation of water in the body. This hormone helps regulate water balance by decreasing urine output and increasing blood volume and pressure when needed.
The breakdown of lactose in the small intestine is mediated by the enzyme lactase, and the products are galactose and glucose. Galactose and glucose are which of the following?
- A. Disaccharides
- B. Oligosaccharides
- C. Polysaccharides
- D. Monosaccharides
Correct Answer: D
Rationale: Galactose and glucose are both simple sugars consisting of single sugar units. Therefore, they are classified as monosaccharides. This makes option D the correct answer.