Microbial Metabolism Chapter 6: Nester

Both anabolism and catabolism happen at?

The same time in a cell.

Catabolism

The set of processes that degrade compounds, releasing their energy. Cells capture that energy and use it to make ATP.

Metabolism

The sum total of all chemical reactions in a cell.

Pentose Phosphate Pathway

This also breaks down glucose, but its primary role in metabolism is the production of compounds used in biosynthesis, including the form of NADPH and 2 precursor metabolites. A product of the pathway feeds into glycolysis.

Glycolysis

This pathway splits glucose and gradually oxidizes it to form two molecules of pyruvate. It provides the cell with a small amount of energy in the form of ATP, some reducing power, and 6 precursor metabolites. This happens in the cytoplasm of a cell.

4ATP, 10NADH, 2FADH2

Total of metabolism

Respiration

Transfers the electrons extracted from glucose to the electron transport chain.

2NADH

Transition step yields....

Electron Carriers

`(Hydrogen Carriers) 1. NAD+ 2. FAD 3. NADP+

Adenosine Diphosphate

(ADP) Can be viewed as the acceptor of free energy.

Adenosine Triphosphate

(ATP) The main energy currency of cells, serving as the ready and immediate donor of free energy. It is composed of ribose, adenine, and three phosphate groups.

Anabolism

(Biosynthesis) The set of processes that cells use to synthesize and assemble the subunits of macromolecules using ATP for energy.

Krebs Cycle

(TCA cycle) As a prelude to other cycles, this is a single reaction called the transition step which converts the pyruvate from glycolysis into acetyl-CoA. This cycle then accepts the 2-carbon acetyl group, ultimately oxidizing it to release 2 molecules of CO2. Generates the most reducing power of all the central metabolic pathways. They also produce 3 precursor metabolites and ATP.

Chemical Reaction

1. Endergonic 2. Exergonic

Metabolic Cast of Characters

1. Enzymes 2. ATP 3. Energy Source 4. Electron Carriers

Central Metabolic Pathways

1. Glycolysis 2. Pentose Phosphate Pathway 3. Intermediate Step 4. Krebs Cycle

Goals of Metabolism

1. Harvest Energy 2. Make stuff for the cell

Goals of Metabolism (revisited)

1. Make ATP from substrate level phosphorylation. 2. Make precursor Metabolites 3. Generate "reducing power" in the form of electron carriers.

Cells make energy in what 3 ways?

1. Respiration 2. Fermentation 3. Photosynthesis

FADH2

2 ATP for every.....

NADH

3 ATP for every....

Electron Transport Chain

A group of membrane embedded electron carriers that pass electrons sequentially from one to another, ejecting protons in the process. In prokaryotes the ET is located in cytoplasm and in eukaryotes it is in the inner membrane of the mitochondria.

Endergonic

A metabolic or chemical process. Accompanied by or requiring the absorption of energy, the products being of greater free energy than the reactants.

Exergonic

A metabolic or chemical process. Accompanied by the release of energy.

Metabolites

A product of a metabolic reaction. It is pulled out into biosynthesis.

Total 38

ATP yield in aerobic respiration

An enzyme catalyzes a chemical reaction by lowering the?

Activation Energy.

Fermentation

Cells break down glucose through glycolysis only and then use pyruvate or a derivative as a terminal electron acceptor. It does not use the electron transport chain.

Light Reactions

Convert radiant energy to ATP. They also generate a reducing power (NADH or NADPH).

The Krebs Cycle occurs in the mitochondria of _______.

Eukaryotes

Lactic Acid, Ethanol

Fermentation yields these interesting end products.

2 ATP, and 2NADH

Glycolysis yields....

2ATP, 6NADH, and 2FADH2

Krebs (TCA) cycle yields....

Intermediate/Transition Step

Needs to happen before pyruvate can enter the Krebs cycle. It is repeated twice for every glucose molecule to oxidize the two pyruvate molecules. It yields 2NADH for every glucose molecule.

Aerobic Respiration

Oxygen serves as the terminal electron acceptor.

The Krebs Cycle occurs in the cytoplasm of _______.

Prokaryotes

Enzymes

Proteins that function as biological catalysts, accelerating the conversion of one substance (Substrate) into another (The Product).

Precursor Metabolites

Serve as carbon skeletons from which subunits of macromolecules can be made. They can be converted into one of any three amino acids: alanine, leucine, or valine.

Anaerobic Respiration

Similar to aerobic respiration but uses a molecule other than oxygen as a terminal electron acceptor. Microbes employ a modified version of the TCA cycle.

Dark Reactions

The calvin cycle is an example.

Photosynthesis

The capture and subsequent conversion of radiant energy into chemical energy. Plants, algae, and several groups of bacteria harvest the radiant energy of sunlight and then use it to power the synthesis of organic compounds from CO2.

Activation Energy

The energy it takes to start a reaction.

Oxidative Phosphorylation

The energy of a proton motive force drives the reaction. Makes ATP from ADP. Need a membrane!

Substrate-Level Phosphorylation

The energy released in an exergonic reaction is used to power the addition of a phosphate group to ADP.