B3 Organisation and the digestive system

Question 1

Mouth

Answer 1

Teeth grind the food into smaller pieces. Salivary glands produce saliva containing amylase

Question 2

Oesophagus/gullet

Answer 2

muscular tube which moves ingested food to the stomach

Question 3

Peristalsis

Answer 3

The relaxing and contracting of the muscles

Question 4

Stomach

Answer 4

Muscular walls pummel the food. Food is mixed with enzyme pepsin. Contains hydrochloric acid

Question 5

Amylase

Answer 5

Helps convert starch to glucose

Question 6

Pepsin

Answer 6

Breaks down proteins

Question 7

Hydrochloric acid in the stomach

Answer 7

creates optimal pH 2 condition for protease enzymes and kills bacteria

Question 8

Small intestine

Answer 8

produce protease, amylase and lipase enzymes to complete digestion. This is where the food is absorbed out of the digestive system into the blood

Question 9

Adaptations of small intestine

Answer 9

covered in villi to increase surface area, has a good blood supply and short diffusion distances to the blood vessels

Question 10

Large intestine

Answer 10

Where excess water is absorbed from the food

Question 11

Liver

Answer 11

Where bile is produced

Question 12

Function of bile

Answer 12

neutralises stomach acid and emulsifies fats

Question 13

Emulsify

Answer 13

breaking up fat globules into smaller droplets

Question 14

Pancreas

Answer 14

Produces protease, amylase and lipase enzymes and releases these into the small intestine

Question 15

Rectum

Answer 15

where the faeces are stored before they pass out of the anus

Question 16

Gall bladder

Answer 16

where bile is stored before it is released into the small intestine

Question 17

what do proteins contain?

Answer 17

carbon, hydrogen, oxygen and nitrogen.

Question 18

what are carbohydrates and fats made up of?

Answer 18

carbon, hydrogen and oxygen.

Question 19

Carbohydrates

Answer 19

Carbohydrates provide energy. There are two types - simple and complex. All carbs are made up of units of sugar

Question 20

simple carbohydrates

Answer 20

they are sugars, like glucose and lactose. They are a fast acting source of energy, like biscuits or energy bars

Question 21

complex carbohydrates

Answer 21

they are a source of slow release energy, like rice and pasta.

Question 22

examples of complex carbohydrates

Answer 22

Cellulose, starch and glycogen are complex carbohydrates. They are long chain of sugars joined together.

Question 23

Lipids

Answer 23

They are the most efficient energy store in the body. When combined with other molecules, lipids are very important in the cell membrane, as hormones, and in the nervous system

Question 24

What are lipids made up of?

Answer 24

three molecules of fatty acids joined to a molecule of glycerol. The glycerol is always the same but the fatty acids vary.

Question 25

Protein

Answer 25

Molecules that contain carbon, hydrogen, oxygen and nitrogen and are made up of long chains of amino acids. They are used for building the cells and tissues of the body and to form enzymes

Question 26

what is protein made up of?

Answer 26

Proteins are made up of long chains of amino acids. | Contain carbon, hydrogen, oxygen and nitrogen

Question 27

what do proteins do?

Answer 27

they act as... | structural components of tissues such as muscles and tendons, hormones such as insulin, antibodies, and enzymes

Question 28

reagent

Answer 28

a chemical that indicates the presence of a substance, usually by changing colour

Question 29

Starch test

Answer 29

add a few drops of iodine to food solution | brown-orange to blue-black

Question 30

Lipid test

Answer 30

Add ethanol to the food to dissolve the fat then add water. | Colourless to white emulsion

Question 31

Sugar test

Answer 31

Add Benedict’s reagent to the food and boil in a water bath. | Blue (minimum) to brick red (maximum)

Question 32

Protein test

Answer 32

Add Biuret reagent to the food. | blue to purple

Question 33

Enzymes

Answer 33

large protein molecules which catalyse chemical reactions.

Question 34

What are enzymes made up of?

Answer 34

long chains of amino acids folded to produce a uniquely shaped active site

Question 35

Active site

Answer 35

the part of the enzyme to which a specific substrate can attach or fit on to

Question 36

Lock and key theory

Answer 36

model which compares the specificity of enzymes with a key and its lock

Question 37

Metabolism

Answer 37

the sum of all the reactions in a cell or in the body

Question 38

affect of temperature on enzyme action

Answer 38

the rate of enzyme-controlled reactions increases as the temperature increases, however this only true for humans up to about 40 degrees c.

Question 39

what happens to the enzyme if it is too hot?

Answer 39

the long amino acid chains begin to unravel, and as a result, the shape of the active site changes.

Question 40

denature

Answer 40

to change the shape of an enzyme's active site. Denatured enzymes no longer work.

Question 41

effect of pH on enzyme action

Answer 41

A change in pH affects the forces that hold the folded chains in place and changes the shape of the molecule. Different enzymes work best at different pH levels

Question 42

carbohydrases

Answer 42

enzymes that break down carbohydrates into simple sugars

Question 43

proteases

Answer 43

enzymes that catalyse the breakdown of proteins to amino acids

Question 44

lipases

Answer 44

enzymes that catalyse the breakdown of lipids to fatty acids and glycerol

Question 45

effect of pH RP

Answer 45

place drops of an amylase, buffer and starch solution into the iodine on the spotting tile at intervals and record the time taken for the disappearance of starch (when the iodine remains the original colour)

Question 46

stomach protease enzymes

Answer 46

work best in acid conditions. The stomach produces hydrochloric acid, which maintains a low pH

Question 47

pancreas and small intestine enzymes

Answer 47

work best in alkaline conditions

Question 48

What is a tissue?

Answer 48

a group of cells with similar structure and function working together

Question 49

What is an organ?

Answer 49

collections of tissues