biological molecules

Question 1

chemical elements in carbs

Answer 1

HOC
Carbon
Oxygen
Hydrogen

Question 2

chemical elements in proteins

Answer 2

PHONCS
Phosphorus
Hydrogen
Oxygen
Nitrogen
Carbon
Sulphur

Question 3

chemical elements in lipids

Answer 3

HOC
Hydrogen
Oxygen
Carbon

Question 4

structure of carbs

as large molecules made up of smaller units

Answer 4

many glucose molecules –> starch/ glycogen

Question 5

structure of proteins

as large molecules made up of smaller units

Answer 5

many amino acids

Question 6

structure of lipids

as large molecules made up of smaller units

Answer 6

1 glycerol molecule

3 fatty acids

Question 7

test for glucose (sugar)

Answer 7

1) add benedicts solution
2) heat

\+ve= orange/red
-ve= blue

Question 8

test for starch

Answer 8

add iodine

\+ve= bluey black
-ve= orange brown

Question 9

role of enzymes as catalysts in metabolic reactions

Answer 9

the substrate fits onto the active site of the enzyme (protein molecule) (like a piece of puzzle) creating an enzyme-substrate complex

the substrate then splits as products leaving the enzyme unchanged.

enzymes need to break down starch, proteins and fats because they are too big to pass through the wall of the gut and into the blood.

Question 10

protein digestion needs what enzyme

Answer 10

protease to make amino acids

Question 11

lipid digestion requires what enzyme

Answer 11

lipase to make fatty acids & glycerol

Question 12

carbohydrate digestion requires what enzyme

Answer 12

it needs 2!
1) amylase
 to make maltose
2) maltase 
 to make glucose

Question 13

how does temperature affect the rate of enzyme- controlled reactions

Answer 13

C- put starch and amylase mixture in water baths of 30, 40, 60, 80*c and on ice
O- use same volume of amylase each time and keep the conc of amylase the same
R- repeat 3 times at each temp
M- time taken for the iodine not to change colour
M- test every 30 secs
S- keep the pH the same.

as the temp goes up, the time goes down, meaning it reacts faster up to 60*c because it then denatures.

Question 14

temp affects on enzyme activity

Answer 14

the rate of reaction increases between 0-40c because the enzyme-substrate molecules have more kinetic energy and are more likely to collide.
40c is the optimum temp
(human temp 37)
above 40*c enzymes denature and substrate molecules can no longer fit into their active sites

Question 15

pH effects on enzyme activity

Answer 15

optimal pH is 8
stomach= acidic (HCL)
small intestine= alkaline
denature, cant bind, cant catalyse.