Enzymes Flashcards
What are enzymes?
Enzymes are biological catalysts that speed up chemical reactions in living organisms.
What part of the enzyme does the substrate molecule bind to?
The active site of the enzyme.
Fill in the blank: Enzymes are made up of __________.
proteins
What is the role of substrates in enzyme reactions?
Substrates are the reactants that enzymes act upon, and that bond to the active site of the enzyme.
What is the ‘lock and key’ model?
The ‘lock and key’ model describes how the substrate bonds perfectly with the active site of the enzyme (as the active site and the substrate are specific to one another), like a key fits into a lock.
What happens to an enzyme when it denatures?
When an enzyme denatures, the structure of the active site is altered, making the substrate molecule unable to bond to the enzyme.
Fill in the blank: The __________ of an enzyme is the temperature/pH at which it is most active.
optimum temperature/pH
What are coenzymes?
Coenzymes are organic molecules that assist enzymes in catalyzing reactions.
Multiple Choice: Which of the following is an example of a coenzyme? A) ATP B) H2O C) CO2 D) NaCl
A) ATP
What is the effect of substrate concentration on enzyme activity?
Low substrate concentration enables a low rate of reaction due to many unoccupied active sites.
Increasing substrate concentration increases enzyme activity up to a point, after which the rate of reaction decreases, due to the low enzyme concentration.
What is the primary function of digestive enzymes?
The primary function of digestive enzymes is to break down food into smaller, absorbable molecules.
True or False: Enzymes are only found in living organisms.
False
What is the significance of enzyme concentration on reaction rate?
Low enzyme concentration reduces the rate of reaction, as there is a greater competition for the limited active sites.
Increasing enzyme concentration generally increases the reaction rate, however, increasing it too much can lower the rate of reaction, due to the lack of substrate molecules.
Fill in the blank: Enzymes are sensitive to changes in __________ and temperature.
pH
What is the function of lactase?
Lactase is an enzyme that breaks down lactose into glucose and galactose.
True or False: Enzymes can function outside their optimum pH range.
True, but their efficiency may be reduced.
What are biological catalysts
Substances that increase the rate of a chemical reaction without being consumed (e.g. enzymes)
What is ATP
ATP is a coenzyme that assists enzymes in catalyzing the reaction of respiration.
What does the substrate bind to the enzyme to form?
An enzyme-substrate complex
What does the enzyme-substrate complex form?
A product and the original enzyme.
What factors affect enzyme activity?
- Temperature
- pH
- Substrate concentration
- Enzyme concentration
How do you calculate the rate of reaction?
Rate of reaction = amount of substrate used or amount of product formed divided by time taken
