Starch and Sugar Lab Quiz

What is the main purpose of using iodine in testing for the presence of starch?

• To catalyze the breakdown of starch into simpler sugars

• To colorimetrically indicate the presence of starch by turning blue-black

• To increase the rate of enzymatic reaction of amylase

• To precipitate starch out of solution

Which test is used to identify reducing sugars in food samples?

• Iodine test

• Biuret test

• Benedict’s test

• Bradford assay

How does Benedict's solution react in the presence of reducing sugars?

• It precipitates as a white solid

• It remains colorless

• It changes color from blue to green, yellow, or brick-red

• It produces a fluorescent glow

What role does amylase play in the breakdown of starches during the lab experiment?

• Amylase catalyzes the hydrolysis of glycosidic bonds, converting starch into maltose and glucose.

• Amylase denatures the starch molecules, making them insoluble.

• Amylase increases the pH, facilitating faster digestion.

• Amylase acts as a buffer, stabilizing the reaction environment.

Which of the following conditions is NOT ideal for the activity of amylase?

• Temperature around 37°C

• High concentrations of salt

• pH close to neutral

• An aqueous, buffered environment

During the enzymatic action of amylase on starch, which type of bond is broken down?

• Peptide bonds

• Glycosidic bonds

• Ester bonds

• Hydrogen bonds

Why is it important to maintain a controlled temperature during the iodine test for starch?

• High temperatures can cause the iodine to evaporate.

• Low temperatures may slow down the rate of the reaction.

• High temperatures can denature the iodine, changing its chemical properties.

• Temperature fluctuations can alter the color response, leading to inaccurate readings.

Tags

NGSS.HS-PS1-5

What does a positive Benedict's test indicate about the sample?

• Presence of peptide bonds

• Presence of unsaturated fats

• Presence of reducing sugars

• Absence of carbohydrates

Which enzyme would you expect to continue the breakdown of maltose produced by amylase action?

• Lipase

• Maltase

• Sucrase

• Lactase

In the context of enzymatic reactions, what does the term 'substrate specificity' refer to?

• The ability of an enzyme to increase reaction rates

• The preference of an enzyme for a particular substrate

• The change in enzyme structure upon substrate binding

• The concentration of substrate required to deactivate an enzyme