Section 1 - Biochemistry Flashcards
What are carbohydrates and lipids (fats and oils) both made up of?
Carbon
Hydrogen
Oxygen
What are proteins made up of?
Carbon Hydrogen Oxygen Nitrogen Phosphorous Sulphur
Describe the structure of carbohydrates
They are:
- simple sugars
- monosaccharides
E.g. glucose is the basic carbohydrate, which join together to make more complex disaccharides and polysaccharides
Describe the structure of proteins
They are:
- made up of amino acids
- amino acids differ depending on what the ‘r’ (rest) is
Describe the structure of lipids
They are:
- made from combining glycerol and three fatty acids
What is the test for glucose?
Heat the object with Benedict’s or Fehling’s Reagent.
If it turns from blue to orange then glucose is present
What is the test for starch?
Apply iodine to the object you are testing
If it turns from red to blue/black then there is starch
Note: in an exam you are safest saying blue/black instead of blue or black
What do enzymes do in metabolic reactions?
Enzymes have the role of a biological catalyst in metabolic reaction. Since they are a catalyst, they must:
1) Lower the activation energy of a reaction - making the reaction faster
2) Be unchanged from the beginning to the end of the reaction
How does heat impact the rate of the functioning of enzymes?
As heat increases, the kinetic energy increases. This means enzymes and substrates move around more, so they are more likely to ‘bump into’ one another (collide) and bind. This means that as heat increases, so does the amount of reactions an enzyme catalyses.
How does the rate of the functioning of enzymes get impacted if the temperature is too high?
If the temperatures are too high, it will denature enzymes, so they cannot function. This is because, energy breaks the bonds that hold the shape of the enzyme: without these the structure will be distorted, which will mean the active site won’t be able to bind with the substrate to break it down.
What is the activation site on an enzyme?
The active site is the area on an enzyme that binds with a substrate to break it down; it is the lock in the lock and key theory
What is the optimum temperature for the functioning of enzymes?
The optimum temperature is where there is lots of energy form heat, but not enough to denature the enzyme. It is different for each enzyme.
What is an experiment that can prove that the enzyme activity can be affected by changes in temperature?
1) Put starch into a test tube and either heat it or cool it
2) Add amylase
3) With this mixture on white tiles, add iodine
4) Time how long it takes for the iodine to stop being blue/black
5) Repeat at different temperatures and compare results
When the iodine stops being blue/black, there is no starch present. Therefore, it must have been digested by the enzymes
What is glucose and starch both examples of?
Carbohydrates
What is the procedure for the iodine test for starch in a solid sample?
1) Peel off the skin of any vegetable e.g. potato and fruits as these are often impermeable. Use a clean spatula to remove samples of powdered food. Avoid cross contamination with other foods
2) Add a few (2-3) drops of bench iodine solution potassium to a piece of solid food on a white tile
3) Make observations
