Exercise 8

Can you detect the presence of contaminating amylase from your experiments?

It is not possible to determine whether contaminating amylase is present because amylase doesn't digest cellulose

Which of the following is/are reducing sugars?

both glucose and polysaccharides

Which of the following is true of enzymes and substrates?

enzymes are specific about the substrates they can act upon

One of the products of the chemical digestion of lipids is

fatty acids

What is the product of lipase hydrolysis?

fatty acids

Pepsin would be most active

in the stomach

With more enzyme activity the optical density

increased

Which of the following is/are true of bile?

it works by a physical process

Which of the following is an end product of starch digestion?

maltose and glucose

A spectrophometer measures

optical density

The results of tube 5 demonstrated that

peptidase does not digest starch

If pepsin were digesting an actual protein substrate, the product would be

peptides and amino acids

The substrate for pepsin is

protein and peptides

The Benedict's assay test for the presence of

reducing sugar

The reagent IKI test for the presence of

starch

Where in the body does protein digestion begin?

the stomach

Explain where and why salivary amylase would be most active.

Salivary amylase would be most active in the mouth because pH 7 is where its peak activity is.

Tubes 3,7, and 8 reveal that

amylase activity was highest at pH 7

Negative results with the negative controls

are expected and validate the experiment

From you results, which pH ideal for pancreatic lipase digestion?

pH 7.0

Proteins and peptides are formed by joining amino acids with a special type of covalent bond called a peptide bond. Which of the following enzymes do you think would be specific for a peptide bond?

peptidase

The substrate(s) for amylase is/are

starch

The substrate for amylase is

starch and carbohydrate

Why was the cellulose in tube 6 hydrolyzed to glucose?

the bacterial suspension contained the enzyme cellulase, which digested the cellulose

Which of the following is true of enzymes?

their activity can be affected by temperature and pH

This activity includes a number of negative controls. Which tube indicates that the amylase solution was not contaminated with maltose?

tube 4

Which tube confirms that there is no lipase in biie salts or vegetable oil?

tube 4

Which two tubes validated the results of the experiment?

tubes 3 and 4

Which tubes indicate that the deionized water did not contain contaminating starch or maltose?

tubes 4,5, and 6

The substrate used in this simulation is

vegetable oil

Hydrolases are enzymes that break down large molecules into smaller subunits through the addition of _____.

water

In this activity the substrate you will be using to detect protein digestion is

BAPNA

Which of the following is not true of controls?

a negative result with a positive control is required to validate the test

When fatty acids are liberated by lipase, the pH

decreases

From your results, where (in theory) would pancreatic lipase be active?

mouth and pancreas