Chapter 8 - Microbial Metabolism Flashcards
What is all chemical reactions and physical workings of the cell called?
Metabolism
What is anabolism and what does it require?
Biosynthesis: synthesis of cell molecules and structures and it Requires energy input
What does Catabolism do and what does it release?
Break the bonds of larger molecules and release energy
What is an enzymes function?
Catalyzing the Chemical Reactions of Life
What is the role of catalysts
Speed up the rate of a chemical reaction without becoming part of the products or being consumed in the reaction
Most enzymes are composed of ______ and may require _______.
Protein
Cofactors
What has unique characteristics such as shape, specificity, and function, as well as an active site for target molecules(substrates)?
Enzymes
What is a reactant molecule upon which and enzyme acts?
Substrates
Enzymes bind to _________ and participate directly in changes to the substrate, Does not become part of the ________, Is not used up by the _______, and Can function over and over again.
substrates
products
reaction
What are nonprotein portion; organic or inorganic (metal ion) structure?
Cofactor
What are organic cofactors called?
Coenzyme
What is an apoenzyme?
Protein portion of the enzyme
What are holoenzyme?
Conjugated enzymes that contain protein and some other nonprotein molecule
What do simple enzymes consist of?
Consist of protein alone
How many protein molecules are there?
5
What is the active or catalytic site?
Actual site where the substrate binds
How and what is the active site formed?
Three-dimensional crevice or groove formed by the way amino acid chains are folded
Each enzyme has how many differences and what are they?
Three; primary structure, variations in folding, and unique active site.
Iron, copper, magnesium, manganese, zinc, cobalt, selenium, etc. are examples of what?
Metallic cofactors
What assists with precise functions between enzyme and substrate, activate enzymes, Help bring the active site and substrate close together, and participate directly in chemical reactions?
Metallic cofactors
What carries and transfers hydrogen atoms, electrons, carbon dioxide, and amino groups, and use vitamins as an important component?
Coenzymes
What is a coenzyme?
Organic compounds that work with the apoenzyme to alter the substrate and Remove a chemical group from one substrate and add it to another substrate
How many classes of enzymes are there?
Six
What are the six enzyme classes?
Oxidoreductases, Lyases, Transferases, Hydrolases, Isomerases, Ligases
What works opposite from oxidoreductases?
Dehydrogenase
What is Oxidoreductases?
Transfer electrons from one substrate to another
What is the transferring a hydrogen from one compound to another called?
Dehydrogenase
What is the transferring of functional groups from one substrate to another?
Transferases
What is hydrolases?
To cleave bonds on molecules with the addition of water
What is lyases?
Add groups to or remove groups from double-bonded substrates
What is the change a substrate to it its isomeric form called?
Isomerases
What is ligases?
To catalyze the formation of bonds with the input of ATP and the removal of water
What are exoenzymes?
They break down large food molecules or harmful chemicals and transport extracellularly
What are endoenzymes?
They are most enzymes of metabolic pathways and retain intracellularly and function there
What are always present in relatively constant amounts, regardless of the cellular environment?
Constitutive enzymes
What are regulated enzymes?
Production is turned on(induced) or turned off(repressed) in response to changes in concentration of substrate
Define denaturation
Weak bonds that maintain the shape of an apoenzyme are broken by heat, low or high pH, or certain chemicals
What is called when the enzymes shape is distorted by disruption, prevent the substrate from attaching to active site, causing the no longer function enzyme to block metabolic rates and leading to death?
Denaturation
What takes a cyclic form?
Metabolic Pathways
What is a metabolic pathway?
Metabolic reactions most often occur in a multistep series or pathway
What is catalyze by an enzyme at each step, the product of one reactant is often the reactant (substrate) for the next, and have alternative methods for nutrient processing?
Metabolic Pathways
What is it when a molecule that resembles the substrate occupies the active site, preventing the substrate from binding, and prevent the enzyme from acting on the inhibitor?
Competitive Inhibition
What are the two binding sites for some enzymes?
The active site and the regulatory site
What is regulated by the binding of molecules other than the substrate to the regulatory site, with the product of the enzymatic reaction often being the regulatory molecule?
No competitive Inhibition
Noncompetitive Inhibition provides negative feedback that?
Slows enzyme activity once a certain concentration of products is reached.
What is Repression?
Stops further synthesis of an enzyme somewhere along its pathway
What is induction?
Enzymes appear (are induced) only when suitable substrates are present
What happens if the end product of an enzymatic reaction reaches excess, the genetic apparatus for replacing enzymes is?
Repressed
What is the name of the reaction that releases energy as they go forward, and energy is available for doing cellular work?
Exergonic reactions
What is the reaction that requires the addition of energy to move forward?
Endergonic reactions
What two reactions are often coupled?
Exergonic and endergonic
What always occurs in pairs?
Redox reactions called redox pairs
What are the redox pairs called?
Electron donor and Electron acceptor
What is final electron acceptor in aerobic metabolism?
Oxygen
What is NAD reduced to?
NADH
What is the most common electron carrier?
NAD
What does NAD carry?
Carries hydrogens and electrons from dehydrogenation reactions
What are the three parts to adenosine triphosphate?
Nitrogen base, Ribose, and Three phosphate group
Removal of phosphates from the three part series releases?
Free energy
Substrate-level phosphorylation is the Generation of ___ through a transfer of a _________ group from a phosphorylated compound directly to ___.
ATP
Phosphate
ADP
ATP utilization and replenishment are?
An ongoing cycle
What is the primary energy currency of the cell?
ATP
When ATP is formed through a series of sunlight-driven reactions in phototrophs it is called?
Photophosphorylation
A series of redox reactions occurring during the final phase of the respiratory pathway is called?
Oxidative phosphorylation
How many basic catabolic pathways are there?
Three
What are the three catabolic pathways called?
Aerobic respiration
Anaerobic respiration
Fermentation
What is the most common pathway used to break down glucose?
Glycolysis
What is aerobic respiration?
Series of reactions that converts glucose to CO_2 and allows the cell to recover significant amounts of energy
What is the pathway for aerobic respiration?
Glycolysis, The Karen’s Cycle, and Respiratory chain
What is Anaerobic Respiration?
Utilizes glycolysis, the Krebs cycle and the respiratory chain but does not use molecular oxygen as the final electron acceptor
What form of catabolism does fermentation pathway use?
Uses only glycolysis
Fermentation is __________ and __________ anaerobes, that do not require ______ but uses organic compounds as ______ acceptors.
Facultative
Aerotolerant
Oxygen
Electron
What is the principal energy-yielding scheme for aerobic heterotrophs?
Aerobic respiration
What provides ATP and metabolic intermediates for other pathways?
Aerobic respiration
Aerobic Respiration is a series of?
Enzyme-catalyze reactions
What is glucose enzymatically converted to?
Pyruvic Acid
What is the first phase of aerobic respiration or the primary metabolic pathway?
Glycolysis
What has pyruvic acid as an essential intermediary metabolite and synthesizes a small amount of ATP anaerobically?
Glyoclysis
What is utilized in several pathways by many organisms?
Pyruvic Acid
Where do strict aerobes and some anaerobes send pyruvic acid to for processing and energy release?
Krebs Cycle
What do facultative anaerobes utilize pyruvic acid into?
Acids or other products
Pyruvic is utilized in several pathways by many organisms and is considered?
A central metabolite
What is the first step of the Krebs cycle?
Pyruvic acid is first converted to acetyl coenzyme A (acetyl CoA) before it enters the Krebs cycle
What is the second step of the Kreb Cycle?
Oxidation reaction releases the first CO_2 molecule
What is the third step of the Kreb Cycle?
A cluster of enzymes and coenzyme A dehydrogenate pyruvic acid to a 2-carbon acetyl group
What is the fourth step of the kreb cycle?
NAD is reduced to NADH
What is the fifth step of the Kreb Cycle?
NADH formed is shuttled to the electron transport system to produce ATP
How many times reactions have to occur since two pyruvates are formed during glycolysis?
All reactions that occur in the Krebs cycle happen twice for each glucose molecule because two pyruvates are formed during glycolysis
The Krebs cycle serves to transfer the ______ stored in ______ ___ to NAD+ and FAD by ______ them
energy
acetyl CoA
reducing
What are the two main products of the kreb cycle?
Reduced NADH and FADH_2
2 ATP produced through substrate-level phosphorylation
What is known as a chain of special redox carriers that receives electrons from NADH and FADH_2, Electrons are passed sequentially from one redox molecule to the next, the Flow of electrons allows the active transport of hydrogens outside the cell membrane, and Oxygen receives hydrogens and electrons and produces water?
Electron Transport System (ETS)
What is another name the Electron Transport System is known as?
The Respiratory Chain
What is stationed along the membrane in close association with the ETS carriers, and captures released energy from the ETS carriers?
ATP synthase
What’s has the following steps; the coupling of ATP synthesis to electron transport, each NADH that enters the ETS gives rise to three ATP molecules, also NAD and FMN enter the ETS at a different point, so there is less energy released, and only give rise to two ATP molecules?
Oxidative phosphorylation
As the electron transport carriers shuttle electrons, hydrogen ions are actively pumped into the periplasmic space or the space between the cell wall and the cytoplasmic membrane, this sets up a concentration gradient of hydrogen ions called the proton motive force, this process is known as?
Chemiosmosis
What is Proton Motive Force?
Consists of a difference in charge between the outside of the membrane (+) and the inside (−)
The proton motive force allows the separation of charges to temporarily store what?
potential energy
What sets the stage for ATP synthesis?
H^+ can only diffuse into the membrane through ATP synthase
Where is the Electron Transport System stationed in Eukaryotes?
ETS is station in mitochondrial membranes, between the mitochondrial matrix and the outer intermembrane space
What is the total possible production of ATP?
40
Where does the 40 ATP come from?
4 from glycolysis
2 from the Krebs cycle
34 from electron transport
How many ATP is produced per molecule of glucose?
38 because you minus 2 ATP expended in early glycolysis
How is the total ATP produced different in some eukaryotic cells?
The total ATP produced may be lower
Define Fermentation
The incomplete oxidation of glucose or other carbohydrates in the absence of oxygen
What does fermentation use as the terminal electron acceptors?
Organic compounds
What does fermentation yield?
Small amount of ATP
Occurs in yeast or bacterial species that have metabolic pathways for converting pyruvic acid to ethanol, decarboxylation of pyruvic acid to acetaldehyde, reduction of acetaldehyde to ethanol, and
NADH formed during glycolysis is oxidized, regenerating NAD and allowing glycolysis to continue are examples of?
Alcoholic fermentation
