2.1.4 Enzymes Flashcards
What are intracellular enzymes? Give an example
Enzymes that act within cells
E.g. catalase
What are extracellular enzymes? Give an example
Enzymes that act outside of the cell
E.g. digestive enzymes amylase and trypsin
What enzyme is needed to break down starch to maltose and where is it produced?
Amylase
Salivary glands and pancreas
What enzyme is needed to break down maltose to glucose and where is it produced?
Maltase
Small intestine
What is the normal temperature coefficient for enzyme controlled reactions?
Two
What is temperature coefficient?
Measure of how much rate of reaction increases with a 10ºC change in temperature
Explain the effects of increasing temperature on enzyme activity?
- Increased kinetic energy so more frequent successful collisions. Rate increases
- Optimum temperature reached. Highest rate of activity
- Bonds vibrate and break. Active site denatures as the tertiary shape changes
What are the adaptations of enzymes in cold environments?
- More flexible structures
- Less stable
- Smaller temperature changes will denature it
What are the adaptations of enzymes in hot environments?
- More stable
- More resistant to change as temperature rises
What is the optimum pH for pepsin and where does it act?
pH 1-2
Stomach
What is the optimum pH for trypsin, lipase and maltase and where does it act?
pH 8
Small intestine
What happens when substrate concentration increases?
- Higher collision rate
- More enzyme-substrate complexes
- Reaches Vmax
- Enzyme concentration becomes limiting factor
Same for increasing enzyme concentration, just substrate concentration becomes limiting factor
What is Vmax?
All of the active sites are occupied by substrates
How to get a higher Vmax on substrate concentration graph?
Increase concentration of enzyme to make more active sites available
How does a competitive inhibitor work?
- Has similar shape to substrate
- Binds to active site temporarily
- Reduced substrates binding so rate of reaction decreases
- Vmax remains same as increasing substrate concentration can overcome effects