B3: Organisation And The Digestive System

Question 1

What are carbohydrates made up of?

Answer 1

Units of sugar

Question 2

Test for sugar?

Colour change?

Answer 2

Benedicts solution

Blue - brick red on heating.

Question 3

What are complex carbs?

Examples?

Answer 3

Made up of long chains of simple sugar units bonded together.

Starch and cellulose.

Question 4

What are simple sugars?

Examples?

Answer 4

They contain only one sugar unit.

Glucose.

Question 5

What are lipids?

Answer 5

Fats (solid) and oils (liquids).

Question 6

What are the most efficient energy store in the body?

Answer 6

Lipids.

Question 7

Test for complex carbs?

Answer 7

(Starch test) yellow red iodine - blue/black

Question 8

What are lipids made up of?

Answer 8

3 molecules of fatty acids bonded to a molecule of glycerol.

Question 9

Test for lipids?

Answer 9

Ethanol, gives a cloudy white layer.

Question 10

What are proteins made of?

Answer 10

Long chains of amino acids, that are coiled and folded to make unique shapes.

Question 11

What happened when a protein is denatured?

Answer 11

The bonds that hold proteins into break and the shape of the protein is lost.

Question 12

Test for proteins?

Answer 12

Biuret regent turns from blue to purple.

Question 13

What are enzymes?

Answer 13

Biological catalysts - they speed up a reaction, whilst remaining unchanged.

Question 14

What do enzymes control in the body?

Answer 14

Metabolism.

Question 15

What are enzymes? (Structure)

Answer 15

Proteins.

Question 16

How do enzymes speed up reactions?

Answer 16

The substrate of the reaction fits into the active site and they join together.

THEY DECREASE THE ACTIVATION ENERGY REQUIRED FOR THE REACTION TO TAKE PLACE.

Question 17

What is metabolism?

Answer 17

The sun of all the reactions in the body.

Question 18

Factors that affect enzyme activity?

Answer 18

Temperature and PH

Question 19

Enzymes that break down carbs?

Answer 19

Amylase.

Question 20

Effect of ph on enzyme action?

Answer 20

The shape of the active site is controlled by forced between different parts of the protein molecule. Change in ph affects the forces so the active site shape changes.

Question 21

D. Denatured?

Answer 21

The breakdown of the molecular structure of a protein so it no longer functions.

Question 22

Optimum temperature for most enzymes?

Answer 22

37 degrees

Question 23

Effect of temperature on enzyme activity?

Answer 23

After about 40 degrees, the protein structure is affected and the long amino acid chains begin to unravel so the shape of the active site changes.

Question 24

Enzymes that break down proteins?

Answer 24

Protease

Question 25

What are proteins broken down into?

Answer 25

Amino acids.

Question 26

What enzyme breaks down fats?

Answer 26

Lipase

Question 27

What are fats broken down into?

Answer 27

Fatty acids and glycerol

Question 28

Where is amylase produced?

Answer 28

Salivary glands and pancreas.

Question 29

Where are carbohydrates digested?

Answer 29

Starch is mostly digested in the small intestine.

Question 30

Where is protease produced?

Answer 30

Stomach, pancreas and small intestine.

Question 31

Where does the digestion/break down of proteins occur?

Answer 31

Stomach and small intestine.

Question 32

Where is lipase produced?

Answer 32

Pancreas and small intestine.

Question 33

Where are lipids broken down?

Answer 33

Small intestine

Question 34

What conditions do the protease enzymes of the stomach work best in?

Answer 34

Acid

Question 35

How does the stomach maintain a low pH?

Answer 35

By producing hydrochloric acid so the protease secreted there can work.

Question 36

How is the acidic liquid from the stomach become alkaline in the small intestine?

Answer 36

The liver produces alkaline bile.

Question 37

Where is bike stored?

Answer 37

Gall bladder

Question 38

Why is bile important? (2 points)

Answer 38

• It neutralises the acidity of the food from the stomach and provides alkaline conditions for the enzymes in the small intestine.
• it also emulsified the fats in your food, so they are broken up into smaller droplets that lipase can act in. (Bigger surface area)

Question 39

Examples of diffusion in the body?

Answer 39

• Urea from cells to the blood plasma that goes to kidneys.

* Digested food molecules from small intestine into the blood

Question 40

Examples of diffusion in plants.

Answer 40

Oxygen and carbon dioxide diffuse during gas exchange.

Question 41

Active transport in the body?

Answer 41

Sugar molecules from gut to blood.

Question 42

Active transport in plants?

Answer 42

Mineral ions and water from soil to roots.

Question 43

Why is it important to add a buffer to the enzyme before the solution is added?

Answer 43

As the reaction will start as soon as the enzyme meets the starch (1). If the buffer is not already mixed with the amylase so the amylase is at the correct pH, you will be changing the pH after the reaction has started (1) and the results will be invalid (1).