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