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BIOCHEM LEC ENZYMES.pdf Flashcards
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BIOCHEM LEC ENZYMES.pdf Flashcards
BIOCHEM LEC ENZYMES.pdf Flashcards
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1
Question
What are enzymes?
Answer
Enzymes are proteins that catalyze chemical reactions in our bodies.
2
Question
What is the importance of enzymes?
Answer
Enzymes are important in nutrient breakdown and chemical building blocks. Enzyme quantity or catalytic activities can help diagnose and predict the prognosis of diseases.
3
Question
What is the enzyme-substrate relationship?
Answer
Enzymes convert substrates into products.
4
Question
What happens to enzymes during catalysis?
Answer
Enzymes may undergo transient modification during catalysis but they are neither consumed nor permanently altered.
5
Question
What is a stereospecific catalyst?
Answer
A stereospecific catalyst typically acts upon only one stereoisomer of a given compound.
6
Question
How do enzymes bind substrates?
Answer
Enzymes bind substrates through at least 3 points of attachment.
7
Question
What are the major classes of enzymes?
Answer
1. Oxidoreductases 2. Transferases 3. Hydrolases 4. Lyases 5. Isomerases 6. Ligases.
8
Question
oxidoreductases
Answer
Oxidoreductases are involved in oxidation and reduction, transferring electrons.
9
Question
What is the difference between oxidation and reduction?
Answer
Oxidation is the loss of electrons, while reduction is the gain of electrons.
10
Question
oxidases
Answer
Oxidases use O2 as an electron acceptor but do not incorporate it into the substrate.
11
Question
What are dehydrogenases?
Answer
Dehydrogenases use molecules other than O2, e.g. NAD, as coenzymes as electron acceptors.
12
Question
What is the function of oxygenases?
Answer
Oxygenases directly incorporate O2 into the substrate.
13
Question
What do peroxidases do?
Answer
Peroxidases use H2O2 as an electron acceptor.
14
Question
What are transferases?
Answer
Transferases catalyze the transfer of groups such as methyl or glycosyl groups from a donor molecule to an acceptor molecule.
15
Question
What are methyltransferases?
Answer
Methyltransferases transfer 1C methyl group units between substrates.
16
Question
What role do aminotransferases play?
Answer
Aminotransferases transfer NH2 from amino acids to keto acids.
17
Question
What do kinases do?
Answer
Kinases transfer PO3 from ATP to a substrate.
18
Question
What are hydrolases?
Answer
Hydrolases catalyze the hydrolytic cleavage of CC, CO, CN, or certain other bonds including acid anhydride bonds.
19
Question
What is the function of phosphatases?
Answer
Phosphatases remove PO3 from a substrate.
20
Question
What do phosphodiesterases do?
Answer
Phosphodiesterases cleave phosphodiester bonds such as those in nucleic acids.
21
Question
What are proteases?
Answer
Proteases cleave amide bonds such as those in proteins.
22
Question
What is the function of lyases?
Answer
Lyases catalyze the cleavage of CC, CO, CN, and other bonds by elimination, leaving double bonds.
23
Question
What are isomerases?
Answer
Isomerases catalyze geometric or structural changes within a single molecule.
24
Question
What do ligases do?
Answer
Ligases catalyze the joining together of 2 molecules coupled to the hydrolysis of a pyrophosphoryl group in ATP or a similar nucleoside triphosphate.
25
Question
What are prosthetic groups?
Answer
Prosthetic groups are tightly stable and are incorporated into a protein's structure by covalent or noncovalent forces.
26
Question
What are cofactors?
Answer
Cofactors bind in a transient dissociable manner either to the enzyme or to a substrate such as ATP.
27
Question
What are coenzymes?
Answer
Coenzymes serve as recyclable shuttles that transport substrates from their point of generation to their point of utilization.
28
Question
What are the roles of vitamin B derivatives?
Answer
Vitamin B derivatives supply important components of numerous coenzymes.
29
Question
What is the mechanism of action for enzymes?
Answer
Enzymes create an environment tailored to a single reaction by providing an active site cleft to shield substrates from solvent and facilitate catalysis.
30
Question
What is acid-base catalysis?
Answer
Acid-base catalysis involves ionizable functional groups of aminoacyl side chains of prosthetic groups contributing to catalysis by acting as acids or bases.