Metabolism Flashcards
Define metabolism
The sum of chemical reactions in an organism
Define catabolism
Energy-releasing process. Exergonic reaction
Breaking down complex organic compounds
Extracts and stores energy in the form of ATP
Define anabolism
Energy-requiring processes Endergonic reactions
Building of complex organic compounds from simpler ones
Utilizes ATP energy
Define metabolic pathway:
A sequence of enzymatically catalyzed chemical reactions in a cell.
Define enzyme
Proteins that are biological catalysts. Specific for its designated chemical reactions.
What causes the specificity of enzymes?
By the 3D shape of the enzyme. “Induced fit” of a substrate into the active site.
Define cofactor
Nonprotein component of active enzyme.
Example: electron carriers.
What are the mechanisms of action of enzymes?
Substrate binds to the enzyme in its active site.
Enzymes positions the substrates in a way that makes the reaction proceed quickly.
Enzymes releases products, and returns to its original state.
Define denaturation
Loss of 3D conformation (shape).
Caused by the breakage of H-bonds and ionic bonds.
Causing the disruption of the active site.
Define competitive inhibitors
Inhibitor that blocks the substrates access to the actie site.
Can be reversible, or irreversible.
Example: Sulfa drugs (has a similar structure to the substrate)
Define noncompetitive inhibition
The inhibitor does not compete with the substrate for the active site. Inhibitor interacts with another area of enzyme (allosteric site); changing the shape of the enzyme’s active site.
Can be reversible or irreversible.
Define oxidation reaction
Reaction that results in the loss of electrons.
Define reduction reaction
Reaction that results in the gain of electrons.
Define ATP
Readily usable energy
Molecule that has unstable high energy bone.
Generated by the phosphorylation of ADP.
How is the energy of catabolic reactions retained to be used by the cell?
In the form of ATP
What are the 3 main steps of cellular respiration?
Glycolysis
Krebs cycle
Oxidative phosphorylation stage
What are the results of glycolysis.
Glycolysis is the oxidation of glucose, producing pyruvic acid.
The electrons are then delivered to the electron transport chain by NADH.
Produces 2 ATP
What are the end results of Krebs cycle?
Pyruvic acid is converted to Acetyl CoA, and oxidized producing CO_2 as a waste product.
Electrons are brought to the electron transport chain by NADH and FADH_2
Produces 2 ATP molecules
What is the electron transport chain?
A series of molecules that are sequentially reduced and oxidized as electrons are passed down the chain. Until it reaches a final electron acceptor at the end of the electron transport chain.
Contains transport proteins that transport H+ ions across the membrane. Forming a proton gradient.
Uses ATP synthase for produces ATP (Chemiosmosis)
Produces 34 ATP molecules.
Define chemoismosis
In the proton gradient of the electron transport chain, the protons diffuse down their gradient, causing energy to be released. ATP synthase uses the energy released to form ATP from ADP.
What is the final electron acceptor in the Electron transport chain during aerobic cellular respiration?
O_2 (oxygen gas)
What is the final electron acceptor in Anaerobic cellular respiration?
Inorganic molecule other than Oxygen gas
-NO_3
-SO_4
-Co_2
Define fermentation
Glycolysis pathway followed by the incomplete oxidation of organic molecules.
Glycolysis produces 2 Pyruvic acid, 2 NADH, and 2 ATP.
Pyruvic acid (or a derivative) is reduced and formed a fermentaion end product.
Does fermentation have one end product?
No, fermentation end products depends on the microbe, the substreate, and the enzymes present or active.
Streptococcus: Lactic acid
Lactobacillus Bacillus: Lactic acid
Saccharomyces: Ethanol and CO_2
Propionibacterium: Propionic acid, acetic acid, CO_2, and H_2.
Clostridium: Butyric acid, butanol, acetone, isopropyl alcohol, and CO_2.
Escherichia: Ethanol, lactic acid, succinic acid, acetic acid, CO_2, H_2.
Salmonella: Ethanol, lactic acid, succinic acid, acetic acid, CO_2, H_2.
Enterobacter: Ethanol, lactic acid, formic acid, butanediol, acetoin, CO_2, H_2.
Define a biochemical tests
Allow us to detect metabolic or enzymatic activity in a cell.
Used to identify unknown bacteria.
Define minimum growth temperature.
The lowest temperature that any growth occurs.
Varies by microbes
Define maximum growth temperature
The highest temperature at which any growth occurs
Varies by microbes
Define optimum growth temperature.
The temperature at which the growth rate is the highest.
Define psychrophiles
Cold loving
Optimum growth temperature: 4-10*C
Define psychrotrophs
Can tolerate cool temperatures
Optimum growth temperature: 20-25*C
Define Mesophiles
Loves moderate temperature
Optimum growth temperature: core body temperature 37*C
Define thermophiles
Heat-loving
Optimum growth temperature: greater than 40C-60C
Define extreme thermophiles
Optimum growth temperature: Greater than 80*C
Define acidophiles
Grows in environments below 5.5 pH
Define neutrophiles
Grows best in environments between pH 5.5-8.5.
Define alkaliphiles
Grows best in environments above pH 8.5.
Define microbial growth
Growth in microbial population.
Increase in number of cells
Define phototroph
Organism that uses light as an energy source
Define chemotroph
Uses organic molecules as an energy source.
Define autotroph
Uses inorganic molecules (CO_2) as a carbon source.
Define Heterotroph
Uses organic molecules as a source of carbon.
