B3 Organisation And Enzymes Flashcards
What is an enzyme?
A biological catalyst
What is a catalyst?
A substance which increases the speed of a reaction, without being changed or used up in the reaction
What is the active site?
A unique shape that fits onto the substances involved in a reaction
What happens if the substrate does not fit into the active site?
The reaction will not be catalysed
What does changing the temperature of an enzyme catalysed reaction do?
Change the rate
What initially happens in an enzyme catalysed reaction with an increase in temperature?
The rate increases
What happens to an enzyme when the temperature gets too high?
The bonds of the enzymes break
This means the active site changes shape so the substrate does not fit
This is when the enzyme is denatured
What is meant by the optimum temperature of an enzyme?
Where the enzyme is most active
this means there are the maximum number of successful collisions between the active site and substrate
How does the pH affect enzymes?
If the pH is too high or too low, the bonds are interfered with. This changes the shape of the active site so denatured the enzyme
What is meant by the optimum pH?
Where the enzyme is most active.
What do you digestive enzymes break down?
A breakdown big molecules into smaller ones
Why do digestive enzymes break down molecules?
The broken down molecules smaller and more soluble so they can pass through the digestive system
This is an absorbed into the bloodstream
What do carbohydrases breakdown?
Carbohydrates into simple sugars
Where is amylase made?
Salivary glands
Pancreas
Small intestine
What do proteases breakdown?
Proteins into amino acids
Where are proteases made?
Stomach – Pepsin
Pancreas
Small intestine
What does lipases convert?
Lipids into glycerol and fatty acids
What are lipids?
Fats and oils
Where are lipases made?
Pancreas
Small intestine
What are the products of digestion used for?
Used to make new carbohydrates, proteins, lipid
Glucose is used for respiration
Where is bile produced and stored?
It is produced in the liver
Stored in the gallbladder
What does bile do?
It’s neutralises the acid from the stomach to make the enzymes in the small intestine work at optimum pH
It’s emulsifies fats to give them a bigger surface area so the enzymes digest them faster
Why is hydrochloric acid produced in the stomach?
To kill bacteria
To give the right pH for protease enzymes
What does Benedict’s reagent test for?
Reducing sugars
What colour does Benedict’s reagent change in the presence of reducing sugars?
From blue to green, yellow or brick red
What does iodine solution test for?
Starches
What colour does iodine solution change to?
From browny orange to black or blue black
What does biuret’s solution test for?
Proteins
What colour does biuret’s solution change to?
From blue to purple
What does Sudan III test for?
It stains lipids
What colour does Sudan III solution change to?
Two separate layers with the top layer being bright red
What are the hazards of food test?
Iodine is an irritant to the eyes
Biuret’s solution is dangerous Sudan three stain solution is flammable
What safety precautions should you take during food tests?
Wear goggles
Wash chemicals of skin
Keep Sudan III stain solution away from Bunsen burners
what is a tissue?
a group of cells with a similar structure and function
what is an organ?
a group of tissues working together for a specific function
what is an organ system?
a group of organs
what does the churning action in the stomach do?
turns food into a liquid so it has a larger surface area to digest
what is a substrate?
the molecule the enzyme breaks down
what are proteins?
long chains of amino acids
why does temperature increase the rate of reaction of an enzyme?
as the temperature increases, the enzyme and substrate are moving faster so there are more collisions per second between the enzyme and the substrate
what are buffer solutions used for?
to control the pH of a solution in investigations
what is the positive result of the ethanol test?
the solution goes from clear to a white cloudy emulsion
what are the adaptations of the small intestine?
very long - provides a very large surface area for absorption
villi - increases surface area
microvilli - increase surface area further
good blood supply - increases concentration gradient
villi have thin membrane - ensures short diffusion path
