Digestion

Question 1

What is digestion?

Answer 1

The breakdown of large insoluble food molecules into smaller, more soluble molecules that can be diffused into the blood

Question 2

What does the mouth do in digestion?

Answer 2

It’s where food enters the alimentary canal and digestion begins

Question 3

What’s the oesophagus do?

Answer 3

Muscular tube that moves ingested food to the stomach

Question 4

What does the stomach do?

Answer 4

Muscular organ where digestion continues

Question 5

What does the pancreas do?

Answer 5

Produce digestive enzymes

Question 6

What does the liver do?

Answer 6

Produced bile

Question 7

What does the large intestine (rectum) do?

Answer 7

Where faeces are stored until ready to leave the body

Question 8

What does the small intestine (duodenum) do?

Answer 8

Where food is mixed with digestive enzymes and bile. Digestion is completed and digested food is diffused into the bloodstream

Question 9

What does the gall bladder do?

Answer 9

Stores bile before releasing it into the duodenum

Question 10

What des the salivary glands do?

Answer 10

Produces saliva containing amylase

Question 11

What are the first 3 steps to the digestion process?

Answer 11

• food enters the digestive sustem through the mouth. This process is called ingestion
• once in mouth, food is chewed to form a ball of food called a bolus
• this passes down the oesoghagus and into the stomach

Question 12

What process is food moved through the tubes of the digestive system called?

Answer 12

Peristalsis

Question 13

What is peristalsis?

Answer 13

• muscles in the gut wall are involved, circular muscles and longitudinal muscles work together to produce wave like contractions
• these have a squeezing action that pushes the bolus through the gut

Question 14

What happens after peristalsis in the gut?

Answer 14

Food is digested through mechanical and chemical processes

Question 15

What is mechanical digestion?

Answer 15

Chewing in the mouth

Churning in the stomach

Question 16

What is chemical digestion?

Answer 16

Involves enzymes, (proteins that function as biological catalysts) form part of digestive juices produced in glands

Question 17

What do all organs in the digestive system have?

Answer 17

Epithelial tissue, which covers the stomach inside and out

Question 18

What does the epithelial tissue allow the stomach to do?

Answer 18

Protects the stomach, helps keep its structure and allows substances to be exchanged through it

Question 19

What does the stomach produce? What does it do?

Answer 19

Produce hydrochloric acid

Kills harmful microorganisms that may have been swallowed with food

Question 20

Where do enzymes in the stomach work best?

Answer 20

In acidic conditions- at a low pH 1-6

Question 21

Where does the food go after it has been in the stomach?

Answer 21

Food travels to the small intestine

Question 22

Where do the enzymes in the small intestine work best in?

Answer 22

Alkaline conditions pH8-14

Question 23

What is bile? Where is it produced and stored?

Answer 23

A substance produced by the liver and stored in the gall bladder

Question 24

What two effects does Bile have in the small intestine?

Answer 24

1) . Neutralises the acid - providing alkaline conditions needed in the small intestine
2) . Emulsifies fat - providing a larger surface area over the enzymes can work

Question 25

What is absorption?

Answer 25

The movement of digested food molecules through the wall of the intestine into the blood and lymph l

Question 26

Which region is digested food absorbed?

Answer 26

Small intestine

Question 27

What does the small intestine have for absorption?

Answer 27

Large internal surface area for absorption to happen quickly and efficiently

Question 28

What are villi?

Answer 28

Tiny finger shaped structures that increase the surface area.

Question 29

What 3 features do Villi have?

Answer 29

1) . Wall just one cell thick - ensures there is only a short distance for absorption to happen by diffusion 2) . Network of blood capillaries- transports digested food eg glucose away from the intestine in the blood 3) . Internal structure a lacteal - transports fatty acids and glycerol from the small intestine in the lymph

Question 30

What does the remaining material of 'digested food' consist of after absorption?

Answer 30

Water, bacteria (living&dead), cells from the lining of the gut and indegestable substances eg cellulose from plant cell walls

Question 31

What does the large intestine do?

Answer 31

Abosrb most of the remaining water

Question 32

What does the remaining mateial leave as it has been going through the large intestine?

Answer 32

Leaves a semi sold waste material called feaces

Question 33

Where do the faeces get stored?

Answer 33

In the rectum

Question 34

What is Egestion?

Answer 34

When the faeces passes out of the body through the anus

Question 35

What are enzymes?

Answer 35

A biological catalyst that helps to speed up chemistry reactions

Question 36

What is the area within the enzyme called?

Answer 36

A active site

Question 37

What are the smaller molecules that fit into the active site called? What does it do?

Answer 37

Substrate | A chemical reaction takes place

Question 38

What do the active site and substrate molecules have? How do they fit?

Answer 38

Have complementary shapes which fit together like a lock and key

Question 39

What is amylase? What does it catalyse the breakdown of and what into?

Answer 39

Type of carbohydrase, catalyses the break down of starch into sugar

Question 40

Where does amylase work?

Answer 40

Mouth and small intestine

Question 41

What does lipase catalyse the breakdown of and what into?

Answer 41

Catalyse the breakdown of fats and oils, into fatty acids and glycerol

Question 42

Where does lipase work?

Answer 42

Small intestine

Question 43

What does protease catalyse the breakdown of and what into?

Answer 43

Catalyses the breakdown of proteins into amino acids

Question 44

Where does protease work?

Answer 44

Stomach and small intestine

Question 45

What happens to the enzyme if it changes shape?

Answer 45

The active site may no longer work, the enzyme has been denatured

Question 46

What two things can enzymes become denatured by?

Answer 46

High temperature and extreme pH

Question 47

What is enzyme activity like with temperature upto 37degrees?

Answer 47

Its gradually increases

Question 48

What happens to enzymes when temperature rise above 40degrees?

Answer 48

The rate of reaction falls rapidly

Question 49

What does heat energy do to the structure?

Answer 49

Damages the enzyme structure, this changes the shape of the active site wich dentaures the enzyme

Question 50

What does the optimum pH for an enzyme depend on?

Answer 50

Depends on where it normally works

Question 51

What happens to the enzyme if the pH is different to its optimum?

Answer 51

Damges the enzymes structure, which leads to the enzyme changing the shape of its active site which denatures the enzyme

Question 52

What is protease used for in industry?

Answer 52

Used to pre-digest proteins during the manufacture of baby foods

Question 53

What is lipase used in industry?

Answer 53

In biological detergents with protease to break down stains into small water soluble substances

Question 54

What is carbohydrase used in industry?

Answer 54

Convert starch into syrup which is relatively cheap and then into sugar syrup in sports drinks

Question 55

What is isomerase used in industry?

Answer 55

Convert glucose syrup into fructose syrup so it can be used in smaller amounts in slimming foods

Question 56

What do enzymes in industry allow companies to do?

Answer 56

Reduce the need for expensive equipment as enzymes allow reactions at normal room temperature and pressures

Question 57

What are the benefits of enzymes in industry?

Answer 57

Cuts costs | Better for the environment since it reduces the amount of fuel and equipment needed

Question 58

What are the disadvantages of enzymes in industry?

Answer 58

Are expensive to produce and can be denatured

Question 59

What is the test for sugars?

Answer 59

Benedicts test | - if sugar is present it will change from blue to green, or yellow to brick red depending on amount of sugar present

Question 60

What is the test for starch?

Answer 60

Iodine solution | - if starch is present it will change from browny orange to black or blue-black

Question 61

What is the test for proteins?

Answer 61

Biuret test | - if protein in present it will change from blue to pink or purple

Question 62

What is the test for lipids?

Answer 62

Sudan III - if lipids are present, mixture will separate into two layers, top layer will be red - (if nothing is present no red layer will form)