B2.3 Enzymes Flashcards
Enzymes act as ______
Catalysts
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
An enzyme doesn’t die, it ________
Denatures
What do enzymes do in the liver?
It breaks down poisonous hydrogen peroxide into non poisonous water and hydrogen
H2O2 —-catalase—-> 2H2O + H2
Define catalyst
A substance which changes the rate of a chemical reaction without being change itself
Define enzyme
A biological catalyst made from proteins
Define enzyme-substrate complex
The enzyme and substrate bound together
Define activation energy
The energy needed for a chemical reaction to take place
Define active site
The special site in the structure of an enzyme where the substrate binds
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.
What factors affect rate of reaction in enzymes? (6)
Temperature pH Enzymes concentration Substrate concentration Surface area Pressure
What’s the optimum temperature of enzymes?
The temperature where enzymes work best at - different enzymes have different optimums
What are the graphs for rate of reaction with a) temperature, b) pH, c) pepsin?
Look them up 👊🏽
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
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
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
What does amylase break down and produce
Starch -> sugars
What does protease break down and produce
Protein -> amino acids
What does lipase break down and produce
Fat -> glycerol + fatty acids
What does catalase react with
Hydrogen peroxide
What does invertase react with
Sucrose
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)
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)
What are the disadvantages of using enzymes in industry (3)
Denature at high temperatures
Sensitive to pH changes
Enzymes can be expensive
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
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
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
What acid is in the stomach to allow pepsin work?
Hydrochloric acid
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
