Microbial Metabolism: Fueling Cell Growth
What is the net production of ATP by glycolysis?
2 ATP.
How many carbons of the pyruvate molecule remain when it is attached to the Coenzyme A?
2 Carbons of pyruvate.
How many turns of the Kreb Cycle occur for every glucose molecule that undergoes cellular respiration?
2 cycles.
For each 6 carbon molecule of glucose that enters glycolysis, how many molecules of pyruvate are made, & how many carbon atoms does each pyruvate have?
2 molecules of pyruvates each with 3 carbon atoms
Cells constantly use ATP to power what kind of reaction?
Endergonic reaction of anabolism
Is the release of an electron from NAD and/or FAD oxidation or reduction?
Oxidation because of losing a H+.
What molecule is the final electron acceptor after the electron has moved through the electron transport chain?
Oxygen.
Fermentation
cells break down glucose via glycolysis & the use pyruvate or a derivative as a terminal electron acceptor
How many pyruvate molecules are made from each glucose molecule?
2 pyruvate molecules are made.
Precursor Metabolites
chemicals that can either be further broken down to generate energy (catabolism) or used to make certain subunits of macromolecules (anabolism).
Certain atoms are more................
electronegative than others, meaning they have a greater affinity (attraction) for electrons
Activation energy
energy it takes to start a reaction
kinetic energy
energy of motion
Substrate-level Phosphorylation
energy released in an exergonic reaction is used to power the addition of Phosphate to ADP
What occurs when an molecule with a low electron affinity moves to one with an higher electron affinity?
energy releases
potential energy
energy stored
Co-factor
enzyme that act as an assistance of a non-protein
The mutual interaction of the active site and the substrate is termed
enzyme-substrate complex
Allosteric
enzymes that can be controlled
Chemolithoautotrophs
play the most significant role in synthesizing organic compounds
oxidation reduction reaction or redox reaction
series that a cell removes electrons from the energy source
If the temperature of an enzyme is too high, what would occur to the protein?
it will denature and no longer function.
Coenzyme
organic cofactors that function as loosely carriers of molecules or electrons
What occurs during the transition step? (3 things)
1. 2 carbon-acetyl group is joined to coenzyme A to form acetyl CoA. 2. CO2 is removed from pyruvate 3. Electrons are transferred from NAD+ , reducing it to NADH+ H+.
When a cell process glucose or other organic molecules through its central metabolic pathways, it does so to generate what three critical things?
1. ATP 2. reducing power 3. precursor metabolites
Rank aerobic respiration, fermentation and anaerobic in order of greatest energy yield to lesser energy yield.
1. Aerobic 2. Anaerobic 3. Fermentation
Describe the transition step & the TCA.
1. TCA cycle oxidizes a 2 carbon acetyl group to release 2 molecules of CO2 2. Together the generate the most reducing power in the central metabolic pathway 3. They produce 3 precursor metabolites & ATP 4. Transition step converts pyruvate from glycolysis into acetyl-CoA
What state to enzyme function best? (2 things)
1. At low salt concentration levels 2. PH values slightly above 7
How many of each molecules are produced in the Kreb Cycle of every glucose molecule that undergoes cellular respiration?
1. CO2~4 2. FADH~2 3. NADH2~6 4. ATP~2
Metabolism is separated into 2 components. What are they?
1. Catabolism 2. Anabolism
What are important electron carriers for the cell? (3 things)
1. FAD/FADH2 2. NAD+/NADH 3. NADP+/NADPH
What are the 3 central Metabolic Pathways?
1. Glycolysis 2. Pentose Phosphate Pathway 3. Tricarboxylic acid (TCA, Kreb Cycle, Citric Cycle)
Where is the highest concentration of Protons (H+) & how do the hydrogen atoms reach this area?
1. Highest concentration of protons is outside the cell. 2. Hydrogen Ions reach this area by the active transport.
Microbial cells need to accomplish two fundamental tasks. What are they?
1. Must synthesize new parts 2. Must harvest energy & convert it to a form that can power various-energy consuming reactions.
Catabolism (2 things)
1. Set of chemical reaction that degrade compounds. 2. Releases energy
Anabolism (AkA~biosynthesis) 2 things
1. Set of chemical reactions that cell use to synthesize & assemble the subunits of macromolecules 2. Uses ATP for energy
How much rise is temperature is necessary to double the speed of enzymatic reactions?
10 degree celcius
Why are the 3 central metabolic pathways referred to as "amphibolic pathways?" (2 things).
1. although they are catabolic, the precursor metabolites & reducing power they generate can be diverted for biosynthesis (anabolism) 2. Amphi means "Both Kinds" which reflects the dual role of these central metabolic pathways.
Oxidative Phosphorylation involves what 2 steps?
1. electron transport chain generates a proton motive force. 2. ATP synthase uses the energy of proton motive force to drive the synthesis of ATP.
Describe respiration (2 things)
1. electrons extracted from glucose are transferred to the electron transport chain 2. Electron Transport Chain uses the electrons to generate a proton motive force that can be used to generate ATP.
Describe fermentation (3 things)
1. glucose is broken down into glycolysis 2. NAD+ is regenerated from NADH by the transfer of electrons to pyruvate or a derivative 3. Fermentation does not involve the TCA cycle
Describe the pentose phosphate pathway (3 things).
1. it yields reducing power in the form of NAPDH 2. It breaks down glucose 3. primary role is the production of compounds used in biosynthesis
Chemoorganotrophs (2 things)
1. obtain energy by degrading organic compounds 2.they use some of that energy to make other organic compounds
Active site (2 things)
1. small crevice (narrow opening) 2. site where the substrate binds by weak force
Chemoorganotrophs use 2 different process to make ATP. What are they?
1. substrate-level phosphorylation 2. oxidative phosphorylation
What is true about glycolysis? (2 things)
1. the pathways splits glucose & oxidizes it to form 2 molecules of pyruvate 2. it provides the cell with a small amount of ATP, some reducing power & 6 precursor metabolites
The carbon atom from glucose end up in pyruvate molecules as a product of glycolysis. How many carbon atoms are in pyruvate molecule?
3 carbon atoms for each pyruvate molecule.
Total theoretical maximum number of ATP created in the ETC from one molecule of glucose is what?
34-36 ATP.
How many carbon atoms are in the glucose molecule
6
What is the name of the embedded protein that provides a channel for the hydrogen ions to pass through the membrane?
ATP Synthase
How are catabolism & anabolism intimately linked?
ATP made during catabolism is used in anabolism.
Can energy be created or destroyed?
Absolutely not. However, it can change from one form to another
What molecule is introduced to the Kreb cycle from the transition step?
Acetyl CoA
How many of the following molecules are produces in the transition step for each glucose molecule that undergoes cellular respiration?
Acetyl-CoA--2 Carbon Dioxide--2 NADH--2
Most coenzymes are derived from certain vitamins particularly a group referred to as.........
B vitamin
Why is energy required to move the hydrogen ions across the membrane?
Because they are going against the concentration gradient.
Scientist look for new supplies of energy by investigating what?
Biofuels
During the transition step, the pyruvic acid molecule is decarboxylated. What molecule is removed during this process?
Carbon Dioxide (CO2)
Cells constantly produce ATP during what type of reaction?
Exergonic reaction of catabolism
Energy released when a chemical bond is broken that is available to do work is called what?
Free energy
Non-Competitive Inhibition (by regulatory molecules)
Inhibitor changes the shape of the enzyme so that the substrate can no longer bind the active site.
Non-Competitive Inhibition (by Enzyme Poison)
Inhibitor permanently changes the shape of the enzyme making the enzyme non-functional.
How does energy exist?
It exists as potential energy & kinetic energy
What molecule serves as an electron acceptor in glycolysis?
NAD
High potential energy electrons provide the energy necessary to pump hydrogen ions across the membrane. What molecules carry these high potential energy electrons?
NAD & FAD
Is any ATP used or produced in the transition step?
No ATP is used/produced in the transition step
Is O2 needed as a reactant in the Kreb Cycle?
No.
Endergonic
Products that have more free energy than the starting compound, the reaction that requires an input of energy.
What is the name of the concentration gradient of protons outside the cell?
Proton Motor Force
When catabolism occurs and energy is released, what do the cells do?
They capture that energy & use it to make ATP
What compound is formed as a final product of the electron transport chain?
Water and ATP.
Terminal electron acceptor
a chemical that accepts the electron from the electron donor
Enzyme
a molecule (usually a protein) that functions as a catalyst, speeding the up the conversion of one substance (substrate) into another product
Metabolic Pathway
a series of chemical reactions that converts a starting compound to an end product.
Metabolic Pathways
a series of sequential chemical reactions that converts a starting compound to an end product
Where did the NAD & FAD (electron acceptors) molecules come from?
came from the Kreb cycle, transition step and Glycolysis
Proton Motive Force
form of energy that results from a electrochemical gradient established by the electron transport chain
What molecule from food is the primary reactant for glycolysis?
glucose
Photosynthetic Organism
harvest the energy of sunlight, using it to power the synthesis of organic compounds from CO2
Chemiosmotic Theory
how the electron transport chain is linked to ATP synthesis.
competitive inhibition
inhibitor binds to the active site of the enzyme; blocking access of the substrate to the site.
Cellular Respiration (AKA~respiration)
involves the transferring of the electrons taken from glucose to the electron transport chain which ultimately donates them to a terminal electron acceptor.
The interaction of an enzyme with its substrate...............
is very specific (think of hand fitting into a glove)
Exergonic
starting compounds have more free energy than the products, energy is released
Reduced
substance that gains electrons (adding of hydrogen~hydrogenation)
Oxidized
substances that loses electrons (removal of hydrogen atom~dehydrogenation)
certain molecules have a greater affinity for electrons.............
than others molecules.
What is it called when an enzyme catalysis a chemical reaction, lowering???
the activation energy
Energy
the capacity to do work
Energy source
the chemical that serves as the electron donor
Free Energy
the energy available to do work.
Adenosine Triphosphate (ATP)
the energy currency of a cell
Oxidative Phosphorylation
the energy of a proton motive force drives a reaction.
Metabolism
the sum of all chemical reactions in a cell
What can metabolic pathways be?
they can be linear, branched or cyclical
The binding of the substrate to the active site causes the shape of the flexible enzyme............................
to change slightly
What is the proton motor force used for?
to turn ATP synthase which then makes ATP.
How is ATP formed?
when you add a phosphate group to ADP (adenosine diphosphate)
Is the change in free energy for a given reaction the same regardless of the number of steps involved?
yes, it is the same
