2.1 Enzymes as Biological Catalysts Flashcards
1
Q
Enzymes are biological catalysts. What are three things catalysts do not change in a chemical reaction?
A
- Equilibrium position
- Change in enthalpy of reaction
- Change in Gibbs free energy of reaction
2
Q
Are enzymes consumed in a chemical reaction
A
No
3
Q
Define enzyme specificity
A
A given enzyme will only catalyze a single reaction or class of reactions with these substrates
4
Q
6 categories of enzymes
A
Lil Hot
1. Oxidoreductases
2. Transferases
3. Hydrolases
4. Lyases
5. Isomerases
6. Ligases
5
Q
Oxidoreductases, give two typical names
A
- Catalyzes oxidation-reduction reactions
- Often have cofactor that acts as an electron carrier
- Dehydrogenase, reductase
- Oxidase - enzymes where oxygen is the final electron acceotor
6
Q
Electron donors are known as _____
A
Reductant
7
Q
Oxidant
A
Electron acceptor
8
Q
Transferase, example of it
A
- Catalyzes movement of functional group from one molecule to another
- Kinases are also transferases, since they catalyze movement of phosphate group from one molecule (generally ATPP) to another
9
Q
Hydrolases
A
- Catalyzes breakdown of a compound into two molecules using water
- Usually named with substrate (eg. phosphatase cleaves phosphate group from single molecule)
- Examples: peptidases, nucleases, lipases
10
Q
Lyases
A
- Catalyze cleavage of one molecule into two
- Differences to hydrolase: does not require water, can also synthesize two molecules into one (then it’s called synthase)
11
Q
Isomerases
A
- Catalyze rearrangement of bonds within a molecule
- Also classified as oxidoreductase, transferase, or lyase, depending on the mechanism
- Also catalyzes reactions between stereo and constitutional isomers
12
Q
Ligases
A
- Catalyze addition or synthesis reactions, especially between large and similar molecules
- Usually addition and synthesis of smaller molecules are catalyzed by lyases
- Often require ATP
- Nucleic acid synthesis and repair
13
Q
Endergonic/exergonic reactions give off energy
A
Exergonic
