Digestive System

Question 1

Test for sugars

Answer 1

Benedicts test - add drops of benedicts solution into sample and put into 75 degree water bath for 5 mins. If sugar is present it will go from blue to green, yellow or brick red

Question 2

Test for starch

Answer 2

Iodine solution - put a few drops of iodine solution into sample and shake. If starch is present solution will go from browny orange to blue/black

Question 3

Tests for protein

Answer 3

Biuret- add even parts of the food sample and biuret solution and mix by shaking. If protein is present solution will go from blue to purple

Question 4

Test for lipids

Answer 4

Sudan 111 test - add 5cm cubed of food sample into test tube, add a couple drops of Sudan 111 stain solution with a pipettes and shake. If containing lipids the mixture will separate into 2 layers top layer = bright red

Question 5

Cells

Answer 5

Basic building blocks that make up all living organisms

Question 6

Tissue

Answer 6

A group of similar cells that work together to carry out a particular function

Question 7

Organ

Answer 7

A group of different tissues that work together to perform a certain function

Question 8

Organ system

Answer 8

A group of organs working together to perform a particular function e.g. the liver, glands

Question 9

Carbohydrases

Answer 9

Convert carbohydrates into simple sugars

Question 10

Proteases

Answer 10

Convert proteins into amino acids

Question 11

Lipases

Answer 11

Convert lipids into glycerol and fatty acids

Question 12

What is bile?

Answer 12

An alkaline as hydrochloric acid in stomach makes the pH too acidic for enzymes in the small intestine to work properly so bile makes the conditions alkaline. The enzymes in the SMALL INTESTINE work best in these alkaline conditions

Question 13

Where is bile produced?

Answer 13

In the liver

Question 14

Where is bile stored?

Answer 14

The gall bladder

Question 15

Where is bile released into?

Answer 15

The small intestine

Question 16

What does bile do?

Answer 16

• makes conditions alkaline
• emulsified fats creating a bigger surface area of fat for lipase to work on -> makes digestion quicker

Question 17

What happens in the stomach?

Answer 17

~ pummels food with it’s muscular walls
~ produces the enzyme protease (called pepsin in the stomach)
~ produces hydrochloric acid to kill bacteria and give the right pH for protease to work

Question 18

What happens in the liver?

Answer 18

Bile is produced

Question 19

What happens in the gall bladder?

Answer 19

Bile is stored before it is released

Question 20

What happens in pancreas?

Answer 20

~ produces PROTEASE, AMYLASE, LIPASE and releases these into the small intestine

Question 21

What happens in the small intestine?

Answer 21

~ produces PROTEASE, AMYLASE, LIPASE to complete digestion
~ digested food is absorbed out of digestive system into the blood

Question 22

What happens in the large intestine?

Answer 22

Excess water is absorbed from food

Question 23

What happens in rectum?

Answer 23

Where the faeces is stored before leaving the body

Question 24

Where are carbohydrases made?

Answer 24

In the salivary glads, pancreas, small intestine

Question 25

Where are proteases made?

Answer 25

Stomach, pancreas, small intestine

Question 26

Where are lipase made?

Answer 26

Pancreas + small instestine

Question 27

What do the digestive enzymes do?

Answer 27

Break down big molecules like starch ,protein + fat into smaller molecules like sugars, amino acids, glycerol and fatty acids. The smaller molecules can pass through the walls of the digestive system easier allowing them to be absorbed into the bloodstream

Question 28

What are the purpose of enzymes?

Answer 28

They speed up useful chemical reactions in the body

Question 29

How do enzymes work?

Answer 29

Every enzymes has an active site with a unique shape that fits onto the substance involved in a reaction therefore they only catalyse one chemical reaction.

Question 30

What could cause an enzyme to denature?

Answer 30

> if the temperature is too high the bonds can break in enzyme causing the active site to change shape and denature
~ if the pH gets too high or too low it will interfere with the bonds holding the enzyme together (enzyme denatures)

Question 31

Amylase

Answer 31

Converts starch to sugar