EXAM 2: Metabolism Flashcards
Metabolism
Chemical processes that occur within a living organism in order to maintain life
Anabolism
The synthesis of complex molecules from simpler ones
Catabolism
The breakdown of complex molecules into simpler ones
Oxidoredeuctase
A class of enzyme that catalyzes oxidation reduction reactions
Transferase
A class of enzyme that catalyzes the transfer of chemical groups between molecules
Hydrolase
A class of enzyme that catalyzes hydrolysis of molecules
Ligase
A class of enzyme that catalyzes the joining of two large molecules by forming a new chemical bond
Lyase
A class of enzyme that catalyzes the breaking of various chemical bonds by means other than hydrolysis and oxidation
Isomerase
A class of enzyme that catalyzes the conversion of a molecule from one isomer to another
Enzyme
A substance produced by a living organism that acts as a catalyst to bring about a specific biochemical reaction
Apoenzyme
An enzyme that requires a cofactor but does not have one bound
Holoenzyme
An apoenzyme together with its cofactor(s)
Allosteric site
Relating to the alteration of a protein’s activity through the binding of an effector molecule at a specific site (that is not the active site)
Define the terms metabolism, catabolism and anabolism and explain how they relate to each other
- Define all three terms!
- Relation
Metabolism
- Catabolism and anabolism are types of metabolism
- Every cell acquires nutrients
Catabolism
- Simple units can be used in anabolic reactions
- releases ATP
Anabolism
- use units broken down from catabolism
- uses ATP
Discuss oxidation-reduction reactions. Explain how electrons are involved. List examples
- OIL RIG lose/gain electrons
- Transfer of electrons from an electron donor to an electron acceptor
- Reactions always occur simultaneously
- Electron carriers that carry electrons from one molecule to the next
Three important electron carriers:
1. NAD+
2. NADP+
3. FADH2
example: A + B—-> A+ and B-
Describe the function and role of enzymes in the cell. Describe common features and how they relate to function.
- Enzymes are organic catalysts & increase the likelihood of a reaction
- They lower the activation energy of a rxn
6 categories of enzymes (common features)
Oxidoreductase
Transferase
Hydrolase
Lyase
Isomerase
Ligase
What are inhibitors?
Discuss methods of enzyme inhibition.
- Inhibitors: Substances that block enzyme activity
Competitive inhibitors
- Shaped such that they fit into an enzyme’s active site and prevent the substrate from binding
- They can bind permanently or reversibly to an active site; reversible competition can be overcome by increase in substrate concentration
Noncompetitive inhibitors
- Do not attach to the active site but instead bind to an allosteric site on the enzyme
- This alters the shape of the active site so that enzymatic activity is reduced or eliminated
Feedback inhibition
- The end-product of a metabolic pathway allosterically inhibits the initial step, shutting down the pathway.
Describe the process cellular respiration, including glycolysis, the Krebs cycle and the electron transport chain.
CR: a metabolic pathway where glucose is catabolized into ATP energy
- Glycolysis
- in cytoplasm
- requires no Oxygen
in: A 6-carbon glucose
out: Net gain of 2 ATP, 2 NADH, and 2 pyruvic acid molecules - Pyruvate Oxidation (acteyl co-A)
- mitochondrial matrix
in: 2 pyruvic acid molecules
out:2 acetyl-CoA, 2 CO2, 2 NADH - Krebs Cycle
- Prok: cytosol, Euk: mit. matrix
- requires Oxygen
in: 2 acetyl-CoA, FAD+, NAD+, ADP + Pi
out: 2 ATP, 2 FADH2, 6 NADH, 4 CO2 - ETC
- Prok: cell membrane, Euk: inner mit. membrane
- requires Oxygen
in: FADH2, NADH, O2, ADP + Pi
out: ~34 ATP, NAD+, FADH
Compare and contrast cellular respiration and fermentation. Discuss the steps involved in each
Glucose catabolized by two processes
Cellular respiration:
- List out all the steps
- Pyruvic acid is completely oxidized to make ATP by redox reactions
Fermentation:
- Yields far less ATP but still generates the necessary NAD+ electron carriers.
- Cells require constant source of NAD+
- Provide cells with alternate source of NAD+
- Uses an endogenous electron acceptor
- Does not fully oxidize glucose
- Doesn’t include ETC or Krebs
- Conversion of pyruvic acid into other organic compounds
Discuss commercial products produced by fermentation process
CO2, ethanol - wine, beer
Acetone- nail polish remover
Identify when oxidative phosphorylation and substrate level phosphorylation occur during glucose metabolism
Substrate level phosphorylation: occurs during glycolysis, the Krebs cycle, and fermentation.
Oxidative phosphorylation: the ETC (chemiosmosis)
