B2b - part 1

Question 1

What are enzymes?

Answer 1

Biological catalysts

Question 2

What is a catalyst?

Answer 2

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

Question 3

What are enzymes made from?

Answer 3

proteins
proteins are made up chains of amino acids.
These chains create the unique shapes

Question 4

Normally what happens in a chemical reaction?

Answer 4

Things are split up or joined together

Question 5

Explain lock and key

Answer 5

All enzymes have a unique shape and only fit one type of molecule. so for reaction to work, enzymes have to fit with this unique shape.
The molecule will fit into the enzymes active site (key) and the enzyme will then split the molecule.

Question 6

How do enzymes work best?

Answer 6

At the right temp and pH
Temp - if too hot then the bonds holding the enzyme together will break and the enzymes special shape will change - denatured - best is around 37 degrees

pH - if too high or too low the pH will break the enzeymes bonds that hold it together and change the special shape - denatured - optimum is 7 (stomach acid - would be 2)

Question 7

What do digestive enzeymes do? (plus e.g)

Answer 7

Break big molecules into small ones

starch,proteins and fats into sugars, amino acids and glycerol.

Question 8

What is amylase?

Answer 8

Converts starch into sugar

Question 9

Where is amylase made?

Answer 9

Salivary glands
pancreas
small intestine

Question 10

What is protease?

Answer 10

Converts protiens into amino acids

Question 11

Where is protease made?

Answer 11

Stomach (known as pepsin)
pancreas
small intestine

Question 12

What is lipase?

Answer 12

Converts lipids into glycerol and fatty acids

Question 13

Where is lipase made?

Answer 13

pancreas

small intestine

Question 14

Job of bile

Answer 14

Prodcued in liver. stored in gall bladder
It neutaralises the acidic hydrochloric acid in the stomach as it is an alkaline
Also breaks down fats so lipase can work on them.

Question 15

Enzeymes in the digestive system

Answer 15

slivary glands - amylase in saliva
Stomach - protease
Pancreas - protease, lipase and amylase
Small intestine -protease, lipase and amylase

Question 16

What is respiration?

Answer 16

The process of releasing energy from glucose which goes on in every cell

Question 17

Equation for aerobic respiration

Answer 17

Glucose + oxygen ——-> CO2 + water + energy

Question 18

What is aerobic respiration?

Answer 18

Respiration using oxygen
happens all the time in plants and animals
happens in mitochondria

Question 19

What is energy made in respiration used for?

Answer 19

• To build up large molecules from small ones (proteins from amino acids)
• In animals, to allow the muscles to contract
• in mammals and birds the energy is used to keep their body temp steady
• In plants to build sugar, nitrates and other nutrients into amino acids which are built into proteins.

Question 20

How does exercise increase heart rate?

Answer 20

More oxygen used to release energy from glucose which is used to contract muscles. More muscle activity requires more glucose and oxygen so the blood then has to flow at a faster rate.
this is why we breath more / deeper and heart pumps faster.

Question 21

Why is glycogen used in exercise?

Answer 21

Glycogen is a form of glucose that has been stored
Each muscles has a supply of it
During exercise muscles need more glucose so glycogen is converted back

Question 22

What happens if the body doesn’t have enough oxygen (what process used)

Answer 22

Muscles start using anaerobic respiration
glucose is used to produce energy however as a consequence lactic acid forms in muscles which causes muscle fatigue
this doesn’t release a lot of energy but keeps muscles going for a little longer.

Question 23

What is anaerobic respiration?

Answer 23

anaerobic means without oxygen

glucose ——-> energy + lactic acid

Question 24

What is oxygen debt

Answer 24

happens after anaerobic respiration
You have to repay the oxygen that you didn’t get to your muscles in time
This is why you breath harder after you stop exercising to get more oxygen in blood
Only reduce when pulse and breathing rate are low.

Question 25

What are enzymes used in?

Answer 25

Biological detergents like washing powders
as they break down animal and plant matter, they’re ideal for removing stains like food and blood
Change foods
proteases put in baby food to digest proteins so its easier for babies to digest

Question 26

Advantages of using enzymes in industry

Answer 26

• Specific - only catalyse the reaction you want them to
• they work at low temps and pressure which reduced the cost
• they work for a long time meaning that they are worthwhile
• biodegradable so cause less environmental pollution

Question 27

Disadvantages of using enzymes in industry

Answer 27

• some can be allergic
• they can be denatured or poisoned so won’t work
• initially expensive
• contamination with other substances effects the reaction