Biochemistry: Enzymes and Their Functions

Questions and Answers

What are the substrate and subunit product of amylase?

Starch and carbohydrate; maltose and glucose (correct)

Nucleic acid and nucleotides; DNA and RNA

Fat and fatty acids; triglycerides

Protein and amino acids; peptides and polypeptides

Boiling denatures the enzyme and inactivates it.

True

At what pH was the amylase activity most active?

pH 7.0

Describe the need for controls in an experiment.

Controls are necessary to validate the results and provide a standard for comparison. Signup and view all the answers

What is the significance of using a 37 degrees Celsius incubation temperature to test salivary amylase activity?

It is around the same temperature as body temperature, ideal for enzyme activity. Signup and view all the answers

Why are the results in tube 1 and tube 2 the same?

In tube 1, amylase is hydrolyzing starch to glucose, and tube 2 has glucose already present. Signup and view all the answers

Describe the results in tube 3 with amylase and cellulose.

Salivary amylase does not digest cellulose. Signup and view all the answers

What is the usual substrate for peptidase?

Peptides and proteins Signup and view all the answers

How do bacteria aid in digestion?

Bacteria break down cellulose that we can't digest. Signup and view all the answers

What effect did boiling have on pepsin?

Boiling inactivated pepsin. Signup and view all the answers

Was your prediction correct about the optimal pH for pepsin activity?

Yes, the correct prediction is pH 2.0. Signup and view all the answers

What would happen if you reduce the incubation time to 30 minutes for tube 5?

It is possible that no digestion of protein would be seen. Signup and view all the answers

Why can't you fully test the lipase activity in tube 5?

The pH is already very low, making it difficult to measure fatty acids released. Signup and view all the answers

Which tube has the highest lipase activity?

Tube #1 has the highest lipase activity. Signup and view all the answers

Explain why pancreatic lipase would be active in both the mouth and the pancreas.

Pancreatic lipase activity is highest at pH 7.0, which is found in both locations. Signup and view all the answers

Describe the process of bile emulsification of lipids.

Bile mechanically breaks up large globules of fat, producing small droplets. Signup and view all the answers

Study Notes

Amylase Function

Substrate for amylase: starch; products: maltose and glucose.
Peak amylase activity occurs at pH 7.0, the same as oral cavity environment.

Enzyme Activity and Temperature

Boiling adversely affects enzyme activity by denaturing it, disrupting its structure and ability to bind substrates.
Optimal incubation temperature for salivary amylase is 37°C, mimicking body temperature for ideal enzyme function.

Control in Experiments

Controls are essential for validation and comparison in experiments; negative controls help identify contaminants.
Tube #5 serves as a negative control to check for contaminating glucose in reagents.

Experimental Observations

In Tube 1 with amylase and starch, hydrolysis occurs resulting in glucose; Tube 2 simply contains pre-hydrolyzed glucose.
Salivary amylase does not digest cellulose, confirmed through negative results in Benedict's test from Tube 3.

Peptidase and Digestion

Peptidase substrates include peptides and proteins.
Bacteria contribute to digestion by breaking down cellulose, which humans cannot digest due to lack of cellulase.

Pepsin Activity

Boiling inactivates pepsin; evidenced by lack of activity in Tube #1 compared to active pepsin in Tube #2.
Optimal pH for pepsin is pH 2.0, correlating with the acidic environment of gastric juice.

Incubation and Lipase Activity

Reducing incubation time for pepsin may prevent significant protein digestion.
Difficulty in measuring lipase activity in Tube 5 due to already low pH, making it challenging to detect fatty acid release.

Lipase and Bile Function

Tube #1 shows highest lipase activity at pH 7.0, aligning with the small intestine's conditions.
Pancreatic lipase functions effectively in both the mouth and pancreas due to similar favorable pH levels.

Bile's Role in Fat Digestion

Bile emulsifies lipids, breaking down large fat globules into smaller droplets, enhancing lipase effectiveness by increasing the lipid's surface area for digestion.

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Description

This quiz explores the functions of amylase and peptidase, including their substrate interactions and optimal conditions for activity. It also covers the importance of controls in enzyme experiments and the effects of temperature on enzyme function, providing a comprehensive look at digestive enzymes.