Nursing practice questions with comprehensive rationales
NurseDive Free Nursing Practice Question
If you take a piece of white bread and chew it slowly for a long period of time, the flavor will become very sweet. This is due to the starch molecules in the bread being digested into smaller sugars that trigger a sweet sensation. Which substance is responsible for this breakdown?
A. Pepsin
Pepsin: pepsin is a stomach protease that digests proteins, not starch.
B. Mucus
Mucus: mucus lubricates and protects tissues but does not chemically digest starch.
C. Salivary amylase
Salivary amylase: salivary amylase (ptyalin) begins starch digestion in the mouth, producing maltose/oligosaccharides that taste sweet.
D. Bicarbonate ions
Bicarbonate ions: bicarbonate neutralizes acid but does not break down starch.
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Full Explanation
A. Pepsin: pepsin is a stomach protease that digests proteins, not starch.
B. Mucus: mucus lubricates and protects tissues but does not chemically digest starch.
C. Salivary amylase: salivary amylase (ptyalin) begins starch digestion in the mouth, producing maltose/oligosaccharides that taste sweet.
D. Bicarbonate ions: bicarbonate neutralizes acid but does not break down starch.
Similar Questions
The salivary glands secrete the enzyme
Full Explanation
A. lipase; lipids: lingual lipase (from tongue) begins lipid digestion, but major salivary secretion is amylase, not lipase.
B. amylase; carbohydrates: salivary (ptyalin) amylase begins digestion of starches (carbohydrates) into smaller sugars.
C. pepsin; proteins: pepsin is secreted as pepsinogen by the stomach, not salivary glands.
D. sucrase; sucrose: sucrase is a brush-border (intestinal) enzyme, not a major salivary gland secretion.
Where are sensory signals from the stomach and small intestine sent to trigger a vomiting reflex?
A. Cerebrum
Cerebrum: the cerebrum is involved in conscious processing; vomiting reflex is coordinated by brainstem centers.
B. Esophagus
Esophagus: the esophagus is a peripheral organ and a route for vomitus, not the control center for the reflex.
C. Pharynx
Pharynx: the pharynx is an anatomical structure involved in expulsion but not the central integrative center for vomiting.
D. Medulla oblongata
Medulla oblongata: the medulla oblongata (brainstem vomiting center and chemoreceptor trigger zone nearby) integrates visceral sensory input and coordinates the vomiting reflex.
Full Explanation
A. Cerebrum: the cerebrum is involved in conscious processing; vomiting reflex is coordinated by brainstem centers.
B. Esophagus: the esophagus is a peripheral organ and a route for vomitus, not the control center for the reflex.
C. Pharynx: the pharynx is an anatomical structure involved in expulsion but not the central integrative center for vomiting.
D. Medulla oblongata: the medulla oblongata (brainstem vomiting center and chemoreceptor trigger zone nearby) integrates visceral sensory input and coordinates the vomiting reflex.
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.
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.