Chapter 8 Final

Metabolism

all chemical reaction with a cell

Anabolism

building into more complex molecules

Catabolism

breaking down complex molecular into simpler ones

Lithotrophs

inorganic compounds

organotrophs

organic compounds

ATP

3 phosphate

ADP

2 phosphate

AMP

1 phosphate

Electron Carrier

 molecules that bind and shuttle high-energy electrons between compounds 

Catalyst

substance that helps speeds up a chemical reaction 

Enzyme

• serves as catalyst for biochemical reactions  

Substrate

• The chemical reactants to which an enzyme binds 

Active Site

where enzyme binds

Cofacotrs

inorganic ions that help stabilize enzyme configuration

Coenzyme

organic helps

Apoenzyme

lacking cofactor or coenzyme h

Hapoenzyme

has cofactor or enzyme

Competitive Inhibitor

• similar enough to substrate that compete for the active site 

  • Needs to equal to concentration work

Allosteric inhibitors

• : binds to the enzyme at allosteric site  

  • Much lower concentration  

Feedback inhib

• involves the use of a pathway product to regulate its own further production  

EMP Path 1st phase

• Energy investment 

• Energy from 2 ATP to modify glucose so 6 C -> 2 phosphorylated three carbon (G3P)

EMP Path 2nd Phase

• : phosphate group is removed from an organic molecule → ADP  

PPP Pathway

• Favores when the cell has need for nucleic acid and/or protein synthesis 

Electron Transport System

 last component of respiration; comprises a series of membrane associated protein complexes

Fermentation

• When respiration is not possible 

  • NADH reoxidized to NAD 

• No ETC 

• No additional ATP beyond glycolysis 

B-Oxidation

• Phospholipases break down phospholipids in cell membranes, causing cell and tissue damage. 

Protein Catabolism

•  the breakdown of proteins into peptides and then amino acids by microbial proteases.

Lightt Dependent Reaction

• Energy from sunlight is absorbed by pigment molecules → stored chemical energy  

Light Independent Reaction

Chemical energy produced by light dependent reaction is used to drive assembly of sugar 

Photosystem (Light harvesting complex)

• Multiple proteins and pigments that may absorb light energy 

Reaction center 

• Pigment molecule that undergoes oxidation upon excited  

light energy to excited electron

Methanotrophs

Oxidize methane

Nitrogen Fixation

Nitrogen to Ammonia

Ammonification

Nitrogen from waste to ammonia

Nitrification

Ammonia to nitrite to nitrate

Denitrification

Nitrate to Nitrogen gas

Sulfur Cycle

Sulfure hydroxide to elemental sulfur to sulfate

Transition reaction/bridge reaction

pyruvate is decarboxylated by complex pyruvate dehydrogenase to 2 carbon acetyl group

Krebs Cycle

transfers remain electrons from the acetyl group to electron carriers

cytoplasm (prokaryote)

Mitochondrial matrix (eukaryotes)

Oxidative phosphorylation

Produces ATP using the proton motive force generated by the electron transport system, which powers ATP synthase.

Electron Transport System

A series of membrane-associated electron carriers that transfer electrons from NADH and FADH₂, releasing energy to pump H⁺ across the membrane and generate a proton motive force.

Proton Motive Force

An electrochemical gradient of H⁺ across a membrane, generated by the electron transport system, that powers ATP synthase to produce ATP.

EMP

The most common glycolysis pathway, breaking down one glucose into two pyruvate molecules and producing a net 2 ATP and 2 NADH.

Substrate level phosphorylation

ATP production through the direct transfer of a phosphate group from a phosphorylated organic molecule to ADP.

ED

produces less ATP than the EMP pathway but also generates NADPH, which provides reducing power for biosynthesis.