Chapter 4- Enzymes Flashcards
What is an enzyme?
An enzyme is a biological catalyst (re-usable) that speeds up metabolic reactions in living organisms without changing the end product.
Define Anabolic and Catabolic:
- Anabolic: involved in synthesis (make muscles, ligaments, cell structures, they build by joining AAs and carbo. together)
- Catabolic: hydrolysis types of reactions (digestion, breaks down e.g. lysosomes contain powerful hydrolytic enzymes)
Draw the graph for Enzyme Action, and explain why reactant energy begins at a figure above 0.
How is activation energy lowered by a catalyst?
- If 2 substrate molecules need joining?
- enzyme holds them together so they can bond easily = synthasase
- If enzyme is catalysing breakdown?
- Fitting into Active Site puts strain on bonds of substrate so they can be broken down easily = hydrolytic.
What is an intracellular enzyme?
Made + retained inside the cell.
E.g. Catalase - breaks down hydrogen peroxide into water + oxygen. (catalase is 1 of the fastest enzymes in body, has ‘high turnover number’, no.molecules catalysed per min = 5.6 million!!!
What is an extracellular enzyme?
E.g. Amylase - works outside of cells.
Amylase- works in saliva to catalyse hydrolysis of starch into maltose.
What is the structure of enzymes?
- Globular Proteins
- 3D shape, almost spherical
- Soluble in water due to position of hydrophobic / hydrophilic R groups
- Contain an ACTIVE SITE
- specific shape (complementary to substrate)
- Where substrate binds to
Describe the lock and key hypothesis of enzymes:
Describe the induced fit theory on enzymes:
According to the Induced Fit Theory, how does the active site change its shape slightly to fit the substrate?
Align the changed ‘R’ groups (H bonds form between delta+ and delta-)
so the attractions temporarily form H bonds and ionic bonds
Causes AS to change shape so not based on shape alone.
Although shape of Active Site should be mostly complementary to substrate.
How does temperature affect enzymes. Draw a graph and explain:
What is the temperature Q10 coefficient?
How does pH affect enzymes?
What are inorganic cofactors?
What are organic cofactors?
What are the two types of inhibition?
what are prosthetic groups?
Draw the inhibitors graph:
What is the abbreviation for Enzyme-Inhibitor Complex:
EHC
Describe Reversible and Irreversible inhibition and how they are different.
Reversible: Weaker H-bonds or weak ionic bonds. The inhibitor can be removed.
Irreversible: Strong Covalent Bonds, the inhibitors cannot be easily removed.
What is Cytochrome C?
A group of enzymes that work together- found in respiration + photosynthesis.
Describe how Snake Venom acts as an inhibitor:
Describe how Cyanide Poisoning act as an inhibitor response:
Describe how Medicinal Inhibitors such as antifreeze work as an inhibitor?
Just look at this card on end-point inhibition.
Define ‘denaturing’:
Denature- change in tertiary structure of protein/enzyme resulting in loss of normal function.
What is Vmax?
Vmax = maximum initial velocity / rate of enzyme-catalysed reaction.
What is co enzyme A?
A co enzyme with important roles in oxidation of pyruvate in Krebs - Cycle + synthesis + oxidation of fatty acids.
