Ch 5 Part 1. Flashcards
Define metabolism
The collection of all the “controlled” biochemical reactions that take part in the cell.
Define catabolism
Breaking down food for energy.
Define anabolism
Using energy to build cell parts.
Define holoenzyme
Active form of enzyme that binds substrate to active (catalytic) site.
Define apoenzyme
protein that forms an active enzyme system by combination with a coenzyme and determines the specificity of this system for a substrate.
Define cofactor
a non- protein chemical compound that is bound to a protein and is required for the protein’s biological activity.
Define catalytic (active) site
region of an enzyme where substrate molecules bind and undergo a chemical reaction.
Define induced-fit model
the binding of a substrate or some other molecule to an enzyme causes a change in the shape of the enzyme so as to enhance or inhibit its activity.
Define saturation point
Enzymes are saturated when there is the maximum amount of substrate present and no more can be absorbed.
Describe how pH, temperature, substrate and enzyme concentrations and inhibitors effect enzyme activity
Can cause an alteration to number of H-bonds which can lead to denatured proteins meaning that without their structure, they have no function.
Distinguish between competitive, non-competitive, and feedback inhibition
Competitive- direct inhibitor, binds to active site on enzyme
Non-competitive- indirect inhibitor, binds to allosteric site of enzyme which causes distortion to active site so that enzyme can no longer fit properly
Feedback inhibition- metabolic product inhibits the first enzyme pathway and as a result the product “feeds back” to start of reaction. Allows for the cell to save substrate and energy as it is recycled.
List and describe the action of the common types of enzymes used in biochemical pathways
- Isomerase- rearranges atoms in a compound
- Transferase- transfer functional group from one compound to another
- Dehydrogenase (oxidoreductase) - remove/transfers e-
- Polymerase (ligases) -join molecules together RNA polymerase and DNA ligase
- Lyases and hydrolases - split molecules apart (hydrolysis)
Distinguish between an endergonic and exergonic reaction
Endergonic- energy absorbed during reaction
Exergonic- energy released during reaction
Describe a redox reaction
A chemical reaction that takes place between an oxidizing substance and a reducing substance. In redox reactions, energy is released when an electron loses potential energy as a result of the transfer.
Label which component is oxidized, and which is reduced
Electron acceptors become reduced (reduction reaction) Reduction Is Gain
Electron donors become oxidized (oxidation reaction) Oxidation Is Loss of e-
Describe the three types of phosphorylation
Where do they occur?
- Substrate lvl- transfer phosphate from a phosphorylated organic compound to ADP (glycolysis)
- Oxidative- energy from redox reaction of respiration is used to attach phosphate to ADP (respiration)
- Photo- light energy is used to start redox reactions that add phosphate to ADP (photosynthesis)
What is the goal of glucose catabolism?
Break down glucose completely to CO2 and release energy
Glycolysis (glucose to pyruvate):
o Is this complete oxidation of glucose?
o How much ATP used? Gained?
o How many NADH generated?
o Does it require oxygen?
o Where does this occur?
In glycolysis, 2 ATP molecules are consumed, producing 4 ATP, 2 NADH, and 2 pyruvates per glucose molecule. Requires O2 (aerobic) and occurs in cytoplasm
Respiration (Synthesis of Acetyl-CoA and Kreb’s Cycle):
o Pyruvate to CO2
▪ Is this complete oxidation of pyruvate?
▪ How much ATP is generated per glucose? How?
▪ How much NADH, FADH2 per glucose?
▪ Where does this occur?
The Krebs cycle takes place exactly in (the mitochondrial matrix) and converts mitochondrial pyruvate into carbon dioxide and water.
Fermentation (pyruvate to waste product(s)):
o What are some waste products?
o Why is this done?
o How much ATP does it generate?
o Does it require oxygen?
o Where does this occur?
.
Respiration, continued (Electron Transport Chain):
o Describe an electron transport chain.
▪ Where is it located?
o What is the final electron acceptor for aerobic respiration?
o What is the final electron acceptor for anaerobic respiration?
o What is the source of the electrons?
o How does a proton gradient form?
o How is ATP produced?
o What’s the name of the enzyme used for phosphorylation?
o What type of phosphorylation is this?
What is the overall reaction for aerobic glucose catabolism? (Glycolysis + aerobic respiration)
Lipid catabolism
o What kind of enzyme breaks triglycerides? (What do you get after this reaction?)
o What is beta oxidation?
o Where does this happen?
Protein catabolism
o What do proteases do? Where are they located?
o What is deamination?
