digestion and ezymes

Question 1

what do carbohydrates become when they are digested by which enzyme ?

Answer 1

carbohydrase/amylase
sugars eg glucose

Question 2

what do lipids become when they are digested by which enzyme?

Answer 2

lipase
fatty acids and glycerol

Question 3

what does protien become when it is digested by which enzyme?

Answer 3

protease
amino acids

Question 4

what is the function of the mouth in the digestive system?

Answer 4

• where chemical and mechanical digestion begins
• chewing breaks down food to increase surface area
• saliva containing amalyse (starch>glucose)

Question 5

what is the function of the oesophagus in the digestive system?

Answer 5

moves food to stomach through peristalsis (strong muscle contractions)

Question 6

what is the function of the stomach in the digestive system?

Answer 6

• muscular walls contract 3x/min to increase surface area of food
• stomach acid kills microbes
• acidic pH perfect for protease

Question 7

what is the function of the liver in the digestive system?

Answer 7

• produces alkaline bile which neutralises stomach acid
• detoxifies blood
• stores carbohydrates as glycogen

Question 8

what is the function of the gall bladder in the digestive system?

Answer 8

• small bag-like structure stores bile
• slowly drains bile into small intestine where it is needed

Question 9

what is the function of the pancreas in the digestive system?

Answer 9

• produces enzymes needed for digestion
• produces isulin to control blood sugar

Question 10

what is the function of the small intestine in the digestive system?

Answer 10

• large surface area to maximise absorption of soluable food
• produces enzymes

Question 11

what is absorption?

Answer 11

where the soluable food passes through the small intstine wall into the blood stream

Question 12

what is the function of the large intestine in the digestive system?

Answer 12

• absorbs water
• solidifies waste

Question 13

what is the function of the anus in the digestive system?

Answer 13

• strong muscle that releases waste

Question 14

what are the parts of the digestive system? (10 in order)

Answer 14

1. mouth
2. oesophagus
3. stomach
4. liver
5. gall bladder
6. pancreas
7. small intestine
8. large intestine
9. rectum
10. anus

Question 15

what is the function of the bile in the digestive system?

Answer 15

• bile emulsifies fat into smaller droplets witha larger surface area increasing the rate of digestion
• bile is allkaline which neutralises stomach acid so that there is the optimum pH for the lipase enzyme

Question 16

why is the small intestine an effective exchange surface? (good at absorption)

Answer 16

• 7m long
• covered in villi (which have very thin permeable membranes , lots of capilleries and good blood flow to mantain high concentratio gradient, increase surface area)

Question 17

what are amino acids used for?

Answer 17

sythesized into new protiens in the ribosomes

Question 18

.

Question 19

what are fatty acids and glycerol used for?

Answer 19

• for energy
• to build cell membranes
• to make hormones

Question 20

what test and colour change detects the presence of starch?

Answer 20

iodine test
orange > black

Question 21

what test and colour change detects the presence of lipids?

Answer 21

emulsion test
colourless > milky white

Question 22

what test and colour change detects the presence of protiens?

Answer 22

biuret test
blue > purple

Question 23

what test and colour change detects the presence of sugar?

Answer 23

benedicts test
blue > brick red

Question 24

how do enzymes work? (lock and key theory)

Answer 24

• large protien molecule which has a specific active site (lock) specific to one type of substrate (key)
• once the substrate is attached to the active site it is changed into the product

Question 25

what factors affect enzyme controlled reactions? (2)

Answer 25

- pH - temperature

Question 27

what are optimum pHs and temps?

Answer 27

- a pH or temp where the enzyme works best - above or below this optimum level, the RoR will slow down

Question 28

what is denaturation?

Answer 28

- if the pH or temperature is too extreme, the shape of the active site will change irreveribly - the enzyme will not work because the substrate cannot fit into the active sit, so it is DENATURED

Question 29

what is an enzyme?

Answer 29

biological catalyst

Question 30

what is the metabolism?

Answer 30

chemical reactions that convert food ito energy

Question 31

what are metabolic pathways?

Answer 31

a series of chemical reactions that start with a substrate and finish with an end product.

Question 32

what is the difference between catabolic and anabolic pathways?

Answer 32

catabolic - release energy - break down (degradation) anabolic - require energy - build up (biosythesis)

Question 33

what is the effect of enzymes of metabolic pathways?

Answer 33

lower activation energy neeeded for reaction to take placee