resporation and enzymes

Question 1

what is a catalyst

Answer 1

a substance which increases the speed of a reaction, without being changed or used up in the reaction

Question 2

what is the role of enzymes as biological catalysts in metabolic reactions

Answer 2

• enzymes act as biological catalysts
• enzymes reduce the need for high temperatures and we only have enzymes to speed up useful reactions in the body. these reactions are called metabolic reactions
• enzymes are all proteins and all proteins are made up of chains of amino acids. these chains are folded up into unique shapes, which enzymes need to do their job.

Question 3

what is a substrate?

Answer 3

a molecule that is changed in a reaction

Question 4

what is an active site?

Answer 4

the part where a substrate joins on to the enzyme

Question 5

what is the lock and key model?

Answer 5

where the substrate and active site join together perfectly to make the enzyme because they fit together like a lock in a key

Question 6

how does temperature change the rate of an enzyme?

Answer 6

as temperature increases so does the rate, because more kinetic energy is put into the enzymes meaning that they speed up and more successful collins are made between the substrate and active site, called enzyme-substrate complexes.

however, if the enzyme gets too hot the shape of the active site changes so that the substrate no longer fits into the enzyme so it is denatured.

Question 7

other than temperature what affects enzymes

Answer 7

pH level

Question 8

what is aerobic respiration

Answer 8

happens when there is plenty of oxygen available and it is the most efficient way of transferring energy from glucose

Question 9

what is anearobic respiration?

Answer 9

when there is not enough oxygen to respire aerobically (respiration without oxygen) lactic acid is produced causing cramps

Question 10

word equation for aerobic respiration

Answer 10

glucose + oxygen —> carbon dioxide + water + energy

Question 11

word equation for anearobic respiration in animals

Answer 11

glucose —> lactic acid + energy

Question 12

word equation for anearobic respiration in plants

Answer 12

glucose —> ethanol + carbon dioxide

Question 13

symbol equation for aerobic respiration

Answer 13

C6H12O6 + 6O2 —> 6CO2 + 6H2O

Question 14

symbol equation for photosynthesis

Answer 14

6CO2 + 6H2O —> C6H12O6 + 6O2

Question 15

investigate the role of anearobic respiration by yeast in different conditions

Answer 15

• mix together sugar, yeast and distilled water, add the mixture to a test tube
• to create aerobic conditions add a layer of oil to prevent oxygen getting to the mixture
• attach a bung with a tube leading to another test tube filled with water.
• sit the test tube with yeast into a water bath of a chosen temperature, give the yeast a few minutes to adjust to the temperature change.
• start a timer and count how many bubbles are produced in the test tube of water over a set time.
• calculate rate of respiration by dividing the the bubbles by the time.
• repeat all steps for different temperatures repeating 3 times at each temp.

Question 16

what should happen to the rate of anearobic respiration by yeast as temperature is increased?

Answer 16

the rate of respiration should increase as temperature increases up until it’s optimum temperature, past that the speed will rapidly decrease as the enzyme will have denatured.