Chap 4: Enzymes

Question 1

What is a catalyst?

Answer 1

A substance that can speed up a chemical reaction without being chemically changed itself.

Question 2

What are enzymes?

Answer 2

Enzymes are proteins that function as biological catalysts, speeding up chemical reactions and remaining unchanged at the end of the reaction.

Question 3

How do enzymes lower activation energy?

Answer 3

Enzymes provide an alternate pathway for the reaction with lower activation energy, making it easier for the reaction to occur.

Question 4

What is the role of enzymes in digestion?

Answer 4

Enzymes involved in digestion are called digestive enzymes, and they help break down large molecules into simpler substances that can be absorbed.

Question 5

What is the lock-and-key hypothesis?

Answer 5

According to the lock-and-key hypothesis, enzymes and substrates have specific complementary shapes, like a lock and key, allowing them to bind together.

Question 6

What is an enzyme-substrate complex?

Answer 6

It is a temporary molecule formed when the substrate binds to the active site of the enzyme, leading to a chemical reaction.

Question 7

What are the characteristics of enzymes?

Answer 7

Enzymes speed up reactions, are specific in their action, required in small amounts, and remain unchanged at the end of the reaction.

Question 8

How are enzymes affected by temperature?

Answer 8

Enzymes are less active at low temperatures, have an optimum temperature where they are most active, and denature at high temperatures.

Question 9

What is denaturation?

Answer 9

Denaturation is the alteration of the three-dimensional structure of an enzyme or protein, usually caused by heat or chemicals, resulting in loss of function.

Question 10

How does pH affect enzymes?

Answer 10

Different enzymes work best at specific pH levels, and deviations from their optimal pH can affect their activity.

Question 11

What is the role of amylase?

Answer 11

Amylase is an enzyme that breaks down starch into smaller sugars like maltose.

Question 12

What is the function of protease?

Answer 12

Protease is an enzyme that breaks down proteins into smaller peptides or amino acids.

Question 13

What is the optimum temperature for human enzymes?

Answer 13

Human enzymes are most active around 40-45 degrees Celsius.

Question 14

How does temperature affect enzyme activity?

Answer 14

Increasing temperature increases enzyme activity until the optimum temperature is reached, after which enzyme activity decreases due to denaturation.

Question 15

What is the importance of enzyme specificity?

Answer 15

Enzyme specificity ensures that enzymes only bind to and catalyze specific substrates, preventing unwanted reactions.

Question 16

What is the significance of enzymes being reusable?

Answer 16

Enzymes can be used repeatedly in reactions, making them highly efficient and allowing a small amount of enzyme to catalyze a large amount of substrate.

Question 17

What is the role of lipase in digestion?

Answer 17

Lipase is an enzyme that breaks down fats into fatty acids and glycerol.

Question 18

How are enzymes affected by denaturation?

Answer 18

Denatured enzymes lose their three-dimensional structure, including their active site, and can no longer function as catalysts.

Question 19

Why do enzymes have an optimum pH?

Answer 19

Enzymes have an optimal pH at which their active site is in the best conformation for catalysis.

Question 20

What happens to enzyme activity when pH deviates from the optimal range?

Answer 20

Enzyme activity decreases when pH deviates from the optimal range, as the conformation of the active site is disrupted.

Question 21

What are the different enzymes involved in digestion?

Answer 21

The enzymes involved in digestion include amylase, protease, lipase, and others specific to breaking down carbohydrates, proteins, and fats.

Question 22

What is the role of amylase in digestion?

Answer 22

Amylase breaks down starch into smaller sugar molecules, such as maltose, to facilitate their digestion and absorption.

Question 23

What is the function of protease in digestion?

Answer 23

Protease enzymes break down proteins into smaller peptides or individual amino acids for digestion and absorption.

Question 24

What does lipase do in digestion?

Answer 24

Lipase is responsible for breaking down fats or lipids into fatty acids and glycerol, enabling their digestion and absorption.

Question 25

What is the significance of peristalsis in digestion?

Answer 25

Peristalsis refers to the rhythmic contractions of the muscles in the digestive tract that propel food along the gut, aiding in digestion and absorption.

Question 26

What is the role of the liver in digestion?

Answer 26

The liver produces bile, which emulsifies fats, making them more accessible to digestive enzymes. It also detoxifies harmful substances and regulates blood glucose levels.

Question 27

What are the main sections of the small intestine?

Answer 27

The small intestine consists of the duodenum, jejunum, and ileum, with the duodenum being the initial part where digestion is primarily completed.

Question 28

What are the functions of the villi in the small intestine?

Answer 28

Villi are finger-like projections in the small intestine that increase the surface area for absorption of digested nutrients into the bloodstream.

Question 29

How do nutrients get absorbed into the bloodstream in the small intestine?

Answer 29

Absorption occurs through the lining of the small intestine, where nutrients diffuse across the epithelial cells and into blood capillaries or the lymphatic system.

Question 30

What is the role of the large intestine in digestion?

Answer 30

The large intestine absorbs water and electrolytes from undigested food, forming and storing feces before elimination.

Question 31

What is the purpose of digestion?

Answer 31

Digestion is the process by which complex food molecules are broken down into simpler forms that can be absorbed and used by the body for energy and growth.

Question 32

What is the difference between mechanical and chemical digestion?

Answer 32

Mechanical digestion involves physical actions, such as chewing and muscular contractions, to break down food into smaller pieces. Chemical digestion involves the action of enzymes to break down complex molecules into simpler forms.

Question 33

What is the role of saliva in digestion?

Answer 33

Saliva contains amylase, which starts the digestion of starch in the mouth, breaking it down into smaller sugar molecules.

Question 34

How does bile aid in digestion?

Answer 34

Bile is produced by the liver and stored in the gallbladder. It emulsifies fats, breaking them down into smaller droplets to enhance their digestion by lipase enzymes.

Question 35

How are nutrients transported to body cells after absorption?

Answer 35

Nutrients absorbed in the small intestine are transported through the bloodstream to body cells, where they are utilized for energy, growth, and repair.

Question 36

What is the role of enzymes in metabolism?

Answer 36

Enzymes are involved in various metabolic pathways, facilitating the conversion of substances, such as glucose, into energy or the synthesis of new molecules.

Question 37

How do enzymes play a role in cellular respiration?

Answer 37

Enzymes catalyze the reactions involved in cellular respiration, breaking down glucose and other molecules to release energy in the form of ATP.

Question 38

What happens to excess glucose in the body?

Answer 38

Excess glucose is converted and stored as glycogen in the liver and muscles for future energy needs.

Question 39

How do enzymes contribute to the synthesis of new molecules?

Answer 39

Enzymes are involved in processes such as protein synthesis, where they help link amino acids together to form polypeptides and ultimately proteins.

Question 40

What is the function of enzymes in the formation of nucleic acids?

Answer 40

Enzymes are essential for DNA and RNA synthesis, enabling the assembly of nucleotides into long chains to form these vital genetic molecules.