B2.3 Enzymes Flashcards Preview

GCSE AQA Biology (old spec) > B2.3 Enzymes > Flashcards

Flashcards in B2.3 Enzymes Deck (29):
1

Enzymes act as ______

Catalysts

2

How do enzymes work?

An enzyme has an active site and using the lock and key mechanism, it fits into the substrate
Substrate splits into products which leave the active site and the enzyme is ready to use again
The active site is a specific shape

3

An enzyme doesn't die, it ________

Denatures

4

What do enzymes do in the liver?

It breaks down poisonous hydrogen peroxide into non poisonous water and hydrogen
H2O2 ----catalase----> 2H2O + H2

5

Define catalyst

A substance which changes the rate of a chemical reaction without being change itself

6

Define enzyme

A biological catalyst made from proteins

7

Define enzyme-substrate complex

The enzyme and substrate bound together

8

Define activation energy

The energy needed for a chemical reaction to take place

9

Define active site

The special site in the structure of an enzyme where the substrate binds

10

Why would a human die if their body temperature reached 50 degrees c?

The enzymes would denature and not be able to break down anything in their body therefore their respiratory system would stop and enzymes allow you to sweat so thermoregulation in your body would stop too. Not enough energy would reach your brain meaning you'd die.

11

What factors affect rate of reaction in enzymes? (6)

Temperature
pH
Enzymes concentration
Substrate concentration
Surface area
Pressure

12

What's the optimum temperature of enzymes?

The temperature where enzymes work best at - different enzymes have different optimums

13

What are the graphs for rate of reaction with a) temperature, b) pH, c) pepsin?

Look them up 👊🏽

14

What is pepsin?

An enzyme in gastric juice that digests protein. It's in the membrane lining the stomach. It can deal with pH 1.5 acidity

15

What's lipase?

And enzyme that breaks down dietary fats into smaller molecules called fatty acids and glycerol
It's mainly in your pancreas but also in your stomach

16

What's amylase?

An enzyme that acts on starch in foods breaking it into smaller carbohydrate molecules. It's made in your saliva and pancreas

17

What does amylase break down and produce

Starch -> sugars

18

What does protease break down and produce

Protein -> amino acids

19

What does lipase break down and produce

Fat -> glycerol + fatty acids

20

What does catalase react with

Hydrogen peroxide

21

What does invertase react with

Sucrose

22

How are enzymes used in industry?

Extracting juice from fruits
Tanning leather
Making cheese and bread
Brewing beer
Baby food (protease breaks down food for them so it's easier to eat)
Biological detergents (enzymes break down stains)

23

What are the advantages of using enzymes in industry? (5)

Work at relatively low temperatures
Work at relatively low pressure
Efficient catalysts
Processes often cheap to run
Sometimes environmentally friendly(less fossil fuels)

24

What are the disadvantages of using enzymes in industry (3)

Denature at high temperatures
Sensitive to pH changes
Enzymes can be expensive

25

What does isomerase do?

It converts the sugar glucose into fructose. Fructose is sweeter than glucose so a smaller amount is needed. This makes it useful in diet foods

26

How are enzymes used in medicine

Finding out if someone has diabetes
Treating cancer - chemotherapy
Testing for pregnancy - the enzyme react with a hormone produced during pregnancy

27

Why are enzymes commonly used to treat/cure/diagnose/control diseases?

They can break down antibodies and antigens and they can differentiate healthy and infected cells

28

What acid is in the stomach to allow pepsin work?

Hydrochloric acid

29

Why do molecules of starch, protein and fat need to be digested? (2)

Large molecules need to be broken down
To allow the nutrients to go through your bloodstream