Digetsion

Question 1

What are enzymes

Answer 1

Proteins that act as biological catalysts, meaning they speed up reactions without being used up

Question 2

How do enzymes work?

Answer 2

They work on molecules known as substrates. The enzymes are complimentary in shape so they only work on certain substrates causing a reaction leaving products

Question 3

What is it called when enzymes and substrates collide?

Answer 3

Enzyme-substrate complex

Question 4

Which enzyme breaks down carbohydrates and what does it get broken into

Answer 4

Carbohydrase, simple sugar, glucose

Question 5

Which enzyme breaks down starch and what does it get broken down into

Answer 5

Amylase. Starch gets broken down into simple sugar glucose

Question 6

What enzyme breaks down protein and what are products of this reaction

Answer 6

Protease, amino acids

Question 7

What does fats/lipids get broken down into and which enzyme reacts with them.

Answer 7

Lipase. Glycerol and fatty acids

Question 8

What is an inhibitor

Answer 8

They are molecules that fit loosely or partially into the active site of some enzymes. They occupy the active site of the enzyme. This means the substrate cannot enter and be broken down leading to a reduced rate of reaction.

Question 9

What factors affect enzyme activity

Answer 9

Temperature, pH and enzyme concentration

Question 10

How does temperature affect enzyme activity?

Answer 10

Higher temperature, more kinetic energy resulting in more collisions between substrates and enzymes. Although eventually enzymes can become too hot and denatured as their complimentary shape will change due to heat.

Question 11

How does pH effect enzyme activity

Answer 11

Deviating from the optimum pH causes the enzymes active site to become denatured and the active site loses its important complimentary shape.

Question 12

How does the concentration of enzymes effect the enzyme activity

Answer 12

The more enzymes the more enzyme-substrate complexes. Eventually this plateaus as there will not be enough substrate molecules

Question 13

What is a thermostable enzyme

Answer 13

An enzyme which can work at a wide range of temperatures

Question 14

Define molecular breakdown

Answer 14

The breakdown of large, complex, insoluble molecules into small simple soluble ones

Question 15

How is food digested in the mouth physically and chemically

Answer 15

Physical: food is torn into smaller pieces by teeth. Food is mixed with saliva

Chemical: Saliva breaks down carbohydrates

Question 16

Physical and chemical digestion in the stomach?

Answer 16

Physical: food, hydrochloric acid and other digestive juices are mixed by the muscular contractions of the stomach wall to form chyme

Chemical: proteins broken down by hydrochloric acid

Question 17

Physical and chemical digestion in small intestine?

Answer 17

Physical: muscles in small intestine help the chyme mix with digestive juices

Chemical: fats, proteins and carbohydrates are broken down into smaller different molecules that can be absorbed by the body’s cells. Most digestion happens here

Question 18

Large intestine physical and chemical digestion?

Answer 18

Physical: water is absorbed back into the body

Chemical: bacteria break down some undigested materials and help produce certain vitamins

Question 19

What is the ileum?

Answer 19

To absorb the digested food products

Question 20

Adaptation of the ileum for absorption?

Answer 20

Large surface area due to it being long and folded

Thin so digested food doesn’t have to travel far to reach the bloodstream.

Permeable so digested food can pass through easily

Good blood supply to maintain the concentration gradient for diffusion between ilium and bloodstream

Villi

Question 21

What are villi

Answer 21

Finger like projections that further increase surface area.

Question 22

Features of the villi that aid absorption?

Answer 22

Good blood supply- large network of Capillaries

Lacteal- a tube that absorbs the products of fat digestion before returning them to the blood

Single layer surface epithelium cells- this reduces the diffusion distance that digested food products have to travel in order to enter the bloodstream.

Permeable- digested food can pass through easily