4.2.2.1 the human digestive system

Question 1

What is the digestive system

Answer 1

It is an example of an organ system in which several organs work together to digest and absorb food.

Question 2

State the order of the digestive system

Answer 2

Mouth, oesophagus, stomach, small intestine, large intestine, rectum, anus.

Question 3

What is metabolism

Answer 3

The chemical processes (requiring energy) that occur within a living organism in order to maintain life.

Question 4

What is a metabolic rate

Answer 4

Speed at which the chemical reactions occur within an organism

Question 5

What happens during digestion

Answer 5

Large food molecules are broken down into small molecules by enzymes. The smalls molecules can then be absorbed into the circulating blood stream, travelling to tissue that needs repairing.

Question 6

What is the function of the mouth

Answer 6

To chew food, enzymes in saliva break down starch into smaller sugar molecules

Question 7

What does the oesophagus do

Answer 7

(Food pipe) this joins mouth and the stomach, food is squeezed to stomach.

Question 8

What does the stomach do

Answer 8

HCl and enzymes digests proteins. Food is churned for hours here.

Question 9

What does the small intestine do?

Answer 9

Small food molecules are absorbed into blood. The small intestine has small walls and villi to increase surface area.

Question 10

What are villi

Answer 10

They help increase the surface area within the small intestine

Question 11

What does the large intestine do

Answer 11

Water absorption and absorption of salts from undigested materials takes place here. The large intestine is the source of excretion, separating waste from wanted nutrients.

Question 12

What does the rectum do

Answer 12

Stores waste until faeces is released into the toilet.

Question 13

What does the liver do

Answer 13

Releases chemicals into small intestine. Bile is released here

Question 14

What is bile

Answer 14

Bile is made in the liver and is stored in the gall bladder. It is alkaline to neutralise hydrochloric acid from the stomach. It also emulsifies fat to form small droplets which increases the surface area.

Question 15

What increases the rate of fat breakdown by lipase

Answer 15

The alkaline conditions and large surface area

Question 16

The products of digestion are used to build new carbohydrates..

Answer 16

Lipids and proteins.

Question 17

Carbohydrases break down … into..

Answer 17

Carbohydrates into simple sugars

Question 18

What does amylase break down and what is it broken down into

Answer 18

Carbohydrates and starches are broken down into glucose

Question 19

Where is amylase found

Answer 19

In saliva and in the pancreas

Question 20

What does protease break down and what is it broken into

Answer 20

Proteins are broken down, into amino acids

Question 21

Where is protease found

Answer 21

In the stomach, small intestine and pancreas

Question 22

What does lipase break down and what is it broken down into

Answer 22

Lipids are broken, broken down into glycerol and fatty acids

Question 23

Where is lipase found

Answer 23

Pancreas and small intestine

Question 24

What are enzymes

Answer 24

They catalyse (speed up) chemical reactions

Question 25

_______ and ____ both emulsify fats, (speeding the reaction up)

Answer 25

Lipase and bile

Question 26

What is an enzymes active site

Answer 26

The groove on their surface

Question 27

What attaches to active sites

Answer 27

Substrates

Question 28

What is a substrate

Answer 28

The surface on which an organism lives on which an enzyme can act.

Question 29

Why are enzymes important during digestion

Answer 29

Enzymes are important as they break down food into certain acids and sugars. The three main enzymes are lipase, protease and amylase. For example, protease breaks down proteins into amino acids which then can be absorbed by the bloodstream. Food needs to be broken down as the molecules are too large to enter the bloodstream, therefore enzymes ensure that they are broken down so that the blood can absorb the useful product and the body can excrete the waste product.

Question 30

What happens to enzymes if they are too cold

Answer 30

They become inactive, meaning, the collisions are decreased with substrates, reducing chance of attachment.

Question 31

What happens to enzymes if they are too hot

Answer 31

They become denatured, meaning the active site changes shape and substrates de-attach

Question 32

Enzymes work best at the ________ Ph

Answer 32

Optimum

Question 33

What happens if the Ph of an enzyme is too high

Answer 33

The enzymes active site changes shape, becoming denatured

Question 34

Depending of the enzyme the ________ pH changes

Answer 34

Optimum

Question 35

What happens if the pH of an enzyme is too low

Answer 35

The active site changes shape and therefore the substrate can no longer fit within it. The enzyme has become denatured