Which of the following enzymes converts starch to soluble sugars?

DSSSB - 29 August 2019 (Shift-1)

Biochemistry & Nutrition

Easy

Appeared in: DSSSB - 29 August 2019 (Shift-1)

Explanation

Amylase is the specific enzyme responsible for the hydrolysis of starch (a complex carbohydrate) into smaller, soluble sugar units like maltose and dextrins.
This digestive process begins in the mouth with salivary amylase (ptyalin) and is completed in the small intestine by pancreatic amylase.
The end products of amylase action are further broken down by other enzymes (like maltase) into glucose, which is then absorbed by the body.
This makes amylase the primary and correct answer for the enzyme that converts starch to soluble sugars.

Option B: Betaine is not an enzyme. It is a compound (a modified amino acid) that functions as a methyl donor in various metabolic pathways. Betaine HCl is a supplement used to increase stomach acidity, not digest carbohydrates.
Option C: Bromelain is a proteolytic enzyme, which means its primary function is to break down proteins, not carbohydrates like starch. It is found in pineapple.
Option D: This is a broad category of enzymes, not a specific enzyme. Proteolytic enzymes, by definition, digest proteins. They do not act on starches.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Enzymatic Digestion of Carbohydrates as background academic context rather than a clinical decision trigger.
A key clinical application is the measurement of serum amylase levels. Elevated levels are a primary diagnostic marker for acute pancreatitis, as a damaged pancreas releases large amounts of amylase into the bloodstream.
Nurses may administer pancreatic enzyme replacements (which include amylase) to patients with conditions like cystic fibrosis or chronic pancreatitis, helping them to properly digest food and absorb nutrients.
What if a patient has pancreatitis? Their secretion of pancreatic amylase would be impaired, leading to poor carbohydrate digestion. This can cause symptoms like bloating, cramping, and osmotic diarrhea due to undigested starch reaching the colon.

How to Approach the Question

First, identify the key terms in the question: 'enzyme', 'starch', and 'soluble sugars'. This points to the topic of carbohydrate digestion.
This is a factual recall question. Access your knowledge of the main digestive enzymes and the macronutrients they act upon.
Mentally categorize the major enzymes: Amylases for carbohydrates (starches), Proteases for proteins, and Lipases for fats.
Evaluate each option against this framework. 'Amylase' directly matches the enzyme for starch digestion.
Eliminate the other options by identifying their function. 'Betaine' is not an enzyme. 'Bromelain' and 'Proteolytic Enzyme' are related to protein digestion, not carbohydrate digestion.
Confirming that amylase is the specific enzyme for starch breakdown leads to the correct answer.

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