food and digestion

Question 1

Fatty acids and glycerol are used

Answer 1

-For energy
-To build cell membranes
-To make hormones

Question 2

amino acids

Answer 2

used for building cell components

Question 3

Glucose

Answer 3

used to supply energy

Question 4

breakdown of fat

Answer 4

Firstly, bile (released by the gall bladder) allows the fat to ‘mix’ with water by breaking the fat into smaller droplets and increases the surface area of fat droplets. This is called emulsification

Secondly, the digestive enzyme lipase breaks each fat molecule into the smaller glycerol and fatty acid molecules.

Question 5

enzymes

Answer 5

Enzymes are biological catalysts and they catalyse most chemical reactions in cells such as respiration, photosynthesis and protein synthesis.

Enzymes are large protein molecules made from a unique sequence of coiled amino acids this gives the active site - the area that is attached to the substrate a very specific shape that fits the substrate exactly

COMPLIMENTARY

Question 6

enzymes function

Answer 6

enzymes help to:
* break down large molecules into smaller ones
* build large molecules from smaller ones.
* Change one molecule into another molecule.

Question 7

temperature effect on enzyme activity

Answer 7

Question 8

glucose food test

Answer 8

Reagent - Benedict’s
Method - add Benedict’s with food into test tube, heat
initial colour – blue
positive result - brick red

Question 9

starch food test

Answer 9

Reagent - iodine
Method - add iodine to food.
initial colour – yellow
positive result – blue/black

Question 10

lipids food test

Answer 10

Reagent - ethanol
Method - mash food in distilled water and pour liquid into test tube, add ethanol, shake and add cold water
initial colour – colourless
positive result – white milky emulsiom

Question 11

Carbohydrase

Answer 11

released in - Salivary glands, Pancreas, small intestine
function - breaks down carbohydrates into sugars e.g. starch into glucose

Question 12

lipase

Answer 12

lipase
released in – pancreas, small intestine
function - breaks down liquids into fatty acids and glycerol

Question 13

protease

Answer 13

released in – stomach, pancreas, small intestine
function - breaks down proteins into amino acids

Question 14

Carbohydrates

Answer 14

for energy

Question 15

fats (lipids)

Answer 15

for energy & making cell membranes

Question 16

protein

Answer 16

for growth and repair

Question 17

minerals

Answer 17

in small amounts to make body chemicals

Question 18

vitamins

Answer 18

in small amounts for cells to work properly

Question 19

fibre

Answer 19

to keep your bowels working

Question 20

water

Answer 20

for chemical reactions to occur + transportation

Question 21

mouth

Answer 21

Your teeth help chop up food here and masticates it. it gives the food a larger surface area for enzymes to work on. this mixes food with saliva making it easier to swallow.

Question 22

saliva

Answer 22

saliva contains Carbohydrase and mucus for lubrication.

Question 23

oesophagus

Answer 23

a muscular tube carrying food from the throat to the stomach. when food enters this tube, the muscles in the oesophagus start to contract & force the food towards the stomach by peristalsis.

Question 24

gastric juice

Answer 24

a mixture of hydrochloric acid mucus and enzymes

Question 25

stomach

Answer 25

muscular bag filled with gastric juice helping chemically digest food down further. There’s also mechanical digestion with the stomach churning the food and turning it into a pulp called chyme.

Question 26

pancreas

Answer 26

This makes a lot of enzymes. E.g. lipase carbohydrase protease.

Question 27

liver

Answer 27

stores some nutrients, vitamins and minerals from digestion, changes them from one form to another and releases them into the blood according to the needs of the body. The liver also makes bile which is stored in the gall bladder but released by the bile duct.

Question 28

small intestine

Answer 28

site of maximum absorption
three liquids are added here:
bile - helps to neutralise acid added to food in the stomach and is the best PH for enzymes to work. it also helps breakdown fats.
Pancreatic and intestinal juices - have enzymes to break food down so nutrients can dissolve into the blood stream

Question 29

Large intestine

Answer 29

Water & Body minerals are absorbed here back into the blood. the remaining non nutritional matter is formed into semisolid brown faeces.

Question 30

Rectum

Answer 30

end of large intestine where faeces are stored

Question 31

anus

Answer 31

the place where the faeces come out

Question 32

protein food test

Answer 32

Reagent - biuret
Method - mash food in distilled water and add to test tube with biuret.
initial colour – blue
positive result – purple / lilac