Nursing practice questions with comprehensive rationales
NurseDive Free Nursing Practice Question
Where are nucleic acids chemically digested?
A. In the mouth
In the mouth: little to no chemical digestion of nucleic acids occurs in the mouth.
B. In the small intestine
In the small intestine: pancreatic nucleases (DNase, RNase) and brush-border enzymes in the small intestine chemically digest nucleic acids into nucleotides and bases.
C. In the large intestine
In the large intestine: the large intestine is primarily for water absorption and microbial fermentation, not major nucleic acid digestion.
D. In the stomach
In the stomach: the stomach mainly digests proteins (pepsin) and does not significantly chemically digest nucleic acids.
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Full Explanation
A. In the mouth: little to no chemical digestion of nucleic acids occurs in the mouth.
B. In the small intestine: pancreatic nucleases (DNase, RNase) and brush-border enzymes in the small intestine chemically digest nucleic acids into nucleotides and bases.
C. In the large intestine: the large intestine is primarily for water absorption and microbial fermentation, not major nucleic acid digestion.
D. In the stomach: the stomach mainly digests proteins (pepsin) and does not significantly chemically digest nucleic acids.
Similar Questions
What is secreted by the parietal cells of gastric glands?
A. Pepsinogen
Pepsinogen: pepsinogen is secreted by chief cells, not parietal cells.
B. Hydrochloric acid
Hydrochloric acid: parietal cells secrete HCl, which acidifies the stomach and helps activate pepsinogen.
C. Mucus
Mucus: mucus is secreted by mucous (surface) cells to protect the gastric epithelium, not by parietal cells.
D. Pepsin
Pepsin: pepsin is the active protease formed from pepsinogen by HCl; parietal cells secrete HCl, not active pepsin.
Full Explanation
A. Pepsinogen: pepsinogen is secreted by chief cells, not parietal cells.
B. Hydrochloric acid: parietal cells secrete HCl, which acidifies the stomach and helps activate pepsinogen.
C. Mucus: mucus is secreted by mucous (surface) cells to protect the gastric epithelium, not by parietal cells.
D. Pepsin: pepsin is the active protease formed from pepsinogen by HCl; parietal cells secrete HCl, not active pepsin.
Which enzyme begins digestion of protein in the stomach?
A. pepsin
pepsin: pepsin (activated from pepsinogen) is the primary enzyme that begins protein digestion in the stomach.
B. amylase
amylase: amylase digests carbohydrates, primarily in the mouth/small intestine, not proteins in the stomach.
C. intrinsic factor
intrinsic factor: intrinsic factor (from parietal cells) is needed for vitamin B₁₂ absorption, not protein digestion.
D. lipase
lipase: lipase digests fats; gastric lipase plays a minor role but is not the main stomach protease.
Full Explanation
A. pepsin: pepsin (activated from pepsinogen) is the primary enzyme that begins protein digestion in the stomach.
B. amylase: amylase digests carbohydrates, primarily in the mouth/small intestine, not proteins in the stomach.
C. intrinsic factor: intrinsic factor (from parietal cells) is needed for vitamin B₁₂ absorption, not protein digestion.
D. lipase: lipase digests fats; gastric lipase plays a minor role but is not the main stomach protease.
What is a function of saliva?
A. Absorbing fat from ingested food
Absorbing fat from ingested food: saliva does not absorb fat; lipid processing occurs later (emulsification by bile, digestion by lipase).
B. Breaking food into smaller pieces
Breaking food into smaller pieces: Incorrect (partly true) -mastication (teeth and jaw) breaks food down; saliva lubricates and moistens but does not mechanically triturate alone.
C. Beginning the chemical digestion of carbohydrates
Beginning the chemical digestion of carbohydrates: saliva contains salivary amylase, which begins starch digestion into smaller sugars.
D. Cleansing the esophagus
Cleansing the esophagus: saliva helps cleanse the mouth and aids swallowing, but it does not “cleanse the esophagus” as a primary function.
Full Explanation
A. Absorbing fat from ingested food: saliva does not absorb fat; lipid processing occurs later (emulsification by bile, digestion by lipase).
B. Breaking food into smaller pieces: Incorrect (partly true) -mastication (teeth and jaw) breaks food down; saliva lubricates and moistens but does not mechanically triturate alone.
C. Beginning the chemical digestion of carbohydrates: saliva contains salivary amylase, which begins starch digestion into smaller sugars.
D. Cleansing the esophagus: saliva helps cleanse the mouth and aids swallowing, but it does not “cleanse the esophagus” as a primary function.