Nokea
Which component of protein contains nitrogen?
- A. Amino group
- B. Carboxyl group
- C. Peptide bond
- D. Side chain
Correct Answer: A
Rationale: The correct answer is the amino group. Amino groups are functional groups found in amino acids, which are the building blocks of proteins. These groups contain nitrogen and are essential for the structure and function of proteins. The carboxyl group (choice B) contains carbon, oxygen, and hydrogen, while the peptide bond (choice C) is a covalent bond formed between amino acids in a protein chain. The side chain (choice D) refers to the unique chemical structure attached to the central carbon of an amino acid and varies among different amino acids, but it does not specifically contain nitrogen.
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What are the small, fingerlike projections into the intestinal lumen called?
- A. Villi
- B. Goblets
- C. Lacteals
- D. Polyps
Correct Answer: A
Rationale: The correct answer is A: Villi. Villi are small fingerlike projections in the intestine that increase the surface area for nutrient absorption. Goblets (choice B) are mucus-secreting cells in the intestines. Lacteals (choice C) are lymphatic vessels in the small intestine that absorb dietary fats. Polyps (choice D) are abnormal tissue growths.
What is the term for the production of glucose from protein, lactate, or glycerol?
- A. glycolysis
- B. gluconeogenesis
- C. glycogenolysis
- D. glucogenesis
Correct Answer: B
Rationale: Gluconeogenesis is the correct term for the production of glucose from non-carbohydrate sources such as protein, lactate, or glycerol. Choice A, glycolysis, is the process of breaking down glucose into pyruvate. Choice C, glycogenolysis, is the breakdown of glycogen into glucose. Choice D, glucogenesis, is not a recognized term in biochemistry.
How many different amino acids make up human proteins?
- A. 9
- B. 13
- C. 15
- D. 20
Correct Answer: D
Rationale: The correct answer is D: 20. There are 20 different amino acids that combine to form proteins in the human body. Each amino acid has a unique side chain that determines its properties. Choices A, B, and C are incorrect as they do not represent the total number of different amino acids found in human proteins.
Regurgitation or reflux of acidic stomach contents back into the esophagus is known as:
- A. hiatal hernia.
- B. diverticulitis.
- C. gastroenteritis.
- D. gastroesophageal reflux disease.
Correct Answer: D
Rationale: The correct answer is D: gastroesophageal reflux disease (GERD). GERD occurs when stomach acid flows back into the esophagus, causing symptoms like heartburn and regurgitation. Choice A, hiatal hernia, is a condition where part of the stomach pushes up into the chest through an opening in the diaphragm. Choice B, diverticulitis, is inflammation or infection of small pouches that can form in the lining of the digestive system. Choice C, gastroenteritis, is inflammation of the stomach and intestines typically caused by a viral or bacterial infection. Therefore, only choice D accurately describes the regurgitation or reflux of acidic stomach contents back into the esophagus.
Which hormone stimulates the gallbladder to contract?
- A. Secretin.
- B. Cholecystokinin (CCK).
- C. Gastrin.
- D. Gastric inhibitory polypeptide (GIP).
Correct Answer: B
Rationale: Cholecystokinin (CCK) is the hormone responsible for stimulating the gallbladder to contract and release bile into the small intestine. Secretin primarily acts on the pancreas to stimulate the secretion of bicarbonate-rich fluid. Gastrin functions in the stimulation of gastric acid secretion, while Gastric inhibitory polypeptide (GIP) plays a role in inhibiting gastric acid secretion and stimulating insulin release.