Enzymes and Digestion

Question 1

What is an enzyme?

Answer 1

A biological catalyst that speeds up chemical reactions in living organisms.

Question 2

What are enzymes made of?

Answer 2

Proteins.

Question 3

What is a catalyst?

Answer 3

A substance that speeds up a chemical reaction without being used up.

Question 4

What is the active site?

Answer 4

The specific region of an enzyme where the substrate binds.

Question 5

What is a substrate?

Answer 5

The substance that an enzyme acts upon.

Question 6

What is the lock and key model?

Answer 6

A model explaining how enzymes work - the substrate fits into the active site like a key into a lock.

Question 7

What is enzyme specificity?

Answer 7

Each enzyme only works on one specific substrate or type of reaction.

Question 8

How does temperature affect enzyme activity?

Answer 8

Higher temperature increases activity up to optimum, then enzymes denature.

Question 9

What is the optimum temperature for human enzymes?

Answer 9

Around 37°C (normal body temperature).

Question 10

What happens when enzymes get too hot?

Answer 10

They denature - the active site changes shape and loses function.

Question 11

How does pH affect enzyme activity?

Answer 11

Each enzyme has an optimum pH; too acidic or alkaline causes denaturation.

Question 12

What is the optimum pH for pepsin?

Answer 12

Around pH 1.5-2 (very acidic).

Question 13

Name three types of digestive enzymes.

Answer 13

Carbohydrases, proteases, and lipases.

Question 14

What do carbohydrases break down?

Answer 14

Carbohydrates into simple sugars.

Question 15

What do proteases break down?

Answer 15

Proteins into amino acids.

Question 16

What do lipases break down?

Answer 16

Lipids (fats) into glycerol and fatty acids.

Question 17

Where is amylase produced?

Answer 17

Salivary glands, pancreas, and small intestine.

Question 18

What does amylase break down?

Answer 18

Starch into maltose (a simple sugar).

Question 19

Where is pepsin produced and what does it do?

Answer 19

Produced in the stomach; breaks down proteins into smaller polypeptides.

Question 20

Where are lipases produced?

Answer 20

In the pancreas and small intestine.

Question 21

What is bile and where is it produced?

Answer 21

A substance produced in the liver that helps digest fats.

Question 22

How does bile help with fat digestion?

Answer 22

It emulsifies fats, breaking them into smaller droplets for easier enzyme action.

Question 23

What does emulsification mean?

Answer 23

Breaking large fat droplets into smaller ones to increase surface area.

Question 24

What is the pH of bile?

Answer 24

Alkaline (around pH 8-9).

Question 25

What are villi?

Answer 25

Small finger-like projections in the small intestine that increase surface area.

Question 26

How are villi adapted for absorption?

Answer 26

Large surface area, thin walls, good blood supply, and lacteal for fat absorption.

Question 27

What happens to amino acids after absorption?

Answer 27

They are carried in the blood to cells for protein synthesis.

Question 28

What happens to glucose after absorption?

Answer 28

It's carried in the blood and used for respiration or stored as glycogen.

Question 29

How do you test for the presence of starch?

Answer 29

Add iodine solution - turns blue-black if starch is present.

Question 30

How do you test for the presence of glucose?

Answer 30

Add Benedict's solution and heat - turns brick red if glucose is present.

Question 31

What is Benedict's solution?

Answer 31

A blue chemical reagent used to test for the presence of reducing sugars.

Question 32

What is Benedict's solution used for?

Answer 32

To test for reducing sugars like glucose, fructose and maltose

Question 33

What colour change occurs when Benedict's solution detects sugar?

Answer 33

Changes from blue to green, yellow, orange, or brick red depending on sugar concentration.