biological molecules

Question 1

carbohydrates contain three kinds of atoms which are

Answer 1

carbon
hydrogen
oxygen

Question 2

what are the simplest kinds of carbohydrates

Answer 2

monosaccharide, ex.glucose

Question 3

what is disaccharide

Answer 3

two molecules of monosaccharide joined together, ex.sucrose and maltose

Question 4

what is polysaccharide

Answer 4

when many simple sugars join together

Question 5

carbohydrates has a chain of?

Answer 5

glucose

Question 6

lipids has a chain of?

Answer 6

fatty acids

Question 7

protein has a chain of?

Answer 7

amino acids

Question 8

lipids contain only three kinds of atoms, which are?

Answer 8

carbon
hydrogen
oxygen

Question 9

what is a fat molecule made of

Answer 9

four smaller molecules joined together, one of these is glycerol attached to three long molecules called fatty acids

Question 10

protein molecules contain?

Answer 10

carbon
hydrogen
oxygen
nitrogen
small amounts of sulfur

Question 11

what is a catalyst

Answer 11

substance that increases rate of chemical reaction and doesn’t change

Question 12

what is an enzyme

Answer 12

protein that functions as biological catalyst

Question 13

what is the lock and key mechanism

Answer 13

the substrate molecule fits into the active site of the enzyme in a key-lock mechanism
the enzyme is the lock and the substrate is the key
after the end of the reaction the enzyme is not used up

Question 14

properties of enzymes

Answer 14

1.all enzymes are proteins
2.lower activation energy of metabolic reaction
3.enzymes work best at certain temperature. usually 37
4.enzymes work best at a specific ph
5.they are catalysts
6.enzymes are specific

Question 15

how does temperature affect enzyme activity

Answer 15

rate of reaction increases as temperature increases, as there is more kinetic energy so more collisions, after reaching optimum temperature enzyme becomes denatured, active site changes

Question 16

how does pH affect enzyme activity

Answer 16

at optimum ph shape of enzyme active site fits exactly into substrate
below or above ph the shape of active site changes

Question 17

effect of substrate concentration on enzyme activity

Answer 17

as the substrate concentration increases the rate of reaction increases, due to more collisions between active site of the enzyme and substrate molecules

Question 18

what are inhibitors

Answer 18

substances that reduce the rate of enzyme catalyzed reaction

Question 19

what is competitive inhibitors

Answer 19

molecules with similar shape to the substrate, they fit into the active site stopping the substrate from entering

Question 20

what is non competitive inhibitors

Answer 20

molecules of different shape than the substrate, they attach to other parts of the enzyme, which changes the shape of the whole enzyme

Question 21

what are immobilized enzymes

Answer 21

enzymes extracted from cells or tissues and used for industrial or medical purposes

Question 22

uses of immobilized enzymes

Answer 22

1.production of lactose free milk
-some people are lactose intolerant, as they don’t have lactase enzyme which breaks down lactose into glucose and galactose, immobilized lactase is used to produce lactose free milk and is inexpensive
2.conversion of sucrose into glucose and fructose
-invertase is used commercially to break down sucrose to produce a mixture of glucose and fructose called invert syrup, invert syrup is used for sweetening products
3.testing for glucose in blood and urine
-test strips for blood or urine glucose level use two immobilized enzymes, the first one is glucose oxidase which catalayses the oxidation of glucose to gluconic acid and hydrogen peroxide, hydrogen peroxide oxidises a colorless organic substance (XH2) to it’s colored form (X). The second reaction is catalysed by immobilised peroxidase enzyme

Question 23

advantages of immobilised enzymes over dissolved enzymes

Answer 23

1.enzymes are more stable at high temperatures and are less likely to denature
2.more resistant to changes in pH
3.less likely to be broken down by organic solvents