Enzymes Flashcards
Define enzyme
A protein that speeds up a reaction, but is not changed by the reaction
- Organic catalyst
- Decreases the amount of energy needed to make the reaction happen
- Reduces activation energy
- Allows reactions to occur fast enough to match the body’s requirements
Define activation energy
The energy needed to start a chemical reaction
Define substrates
Molecules that enzymes react with
Factors affecting enzyme activity
- Concentration
- Temperature
- pH
- Presence of co-factors
How does concentration affect enzyme activity?
- More concentration = faster reactions
How does temperature affect enzyme activity?
- Higher temperature = faster reactions (up to 50 degrees)
- Denature
How does pH affect enzyme activity?
Acidity
How does the presence of co-factors affect enzyme activity?
Required for reaction to take place
Define denatured
When an enzyme is not able to function properly due to changes in its active site
Define catabolic
Breaking down a large molecule to smaller molecules
Define anabolic
Small molecules combined to make a large molecule
Why do cells need energy to do work?
- Make new molecules
- Building membranes and organelles
- Moving molecules in and out of the cell
- Movement
Types of metabolism
- Catabolism
- Anabolism
Where does a cell get energy?
- Food is broken down to a form the cell can use
- Extra energy is stored in the ATP molecule, a nucleotide
Define ATP
- Adenosine triphosphate
- A molecule made up of adenine, ribose and 3 phosphate groups
How does ATP work?
- Energy is stored in the bond between the second and third phosphate group
- When bond is broken, energy is released and ADP is formed
ADP
Adenosine diphosphate
Equation for ATP (energy currency)
ATP ADP + Phosphorus + Energy
How do cells make energy?
- Cells make energy via respiration
- Mostly takes place in the mitochondria
Equation for respiration
O2 + Glucose –> CO2 + Water + Energy
Define respiration
The process of breaking down food molecules to release energy
- Occurs in the mitochondria
Types of respiration
- Aerobic (requires oxygen)
- Anaerobic (requires an absence of oxygen)
Define cellular respiration
The process where organic molecules from food are broken down in the cells to release energy. Examples: - Glucose - Amino acids - Fatty acids - Glycerol
What can the energy from the breakdown of foods be used for?
- Building complex molecules
- Cell division/growth
- Movement of cell organelles and whole cells
- Maintaining cell organisation
- Active transport
- Transmission of nerve impulses
How is the energy stored from cellular respiration?
- As glucose is broken down, 60% of the energy released is heat, used to maintain body temperature
- Remaining energy is used to form ATP