chapter 8 | Metabolism

Potential energy

Energy stored due to location/position!

• held/stored ready to be used

Kinetic energy

Energy associated with motion

• In kinetic energy: working to get energy

• Out kinetic energy: released energy out

ATP

Energy currency of cells

• One a denoting, robust sugar, and three phosphate groups

Adenosine Triphosphate

• through hydrolysis it releases energy

• The bond between the 2nd and 3rd phosphate s hydrolyzed

First law of thermodynamics

Energy can be transferred but not created/destroyed

Second law of thermodynamics

Transfer/transformation not 100% efficient

Energy transfer/transformation releases entropy (disorder) of the universe

ATP

Phosphate groups are unstable

Hydrolysis reaction: makes ADP+energy

Reaction is reversible

ATP (charged) →H2O in (hydrolysis)→ADP (energy low)→H2O out (ATP is charged)

Metabolism

All the reactions that a cell or organism makes to sustain life

• Cells use the bonds in carbon and other molecules for energy

Metabolism

How cells obtain carbon depends on type of cell

• 2 types of this: autotrophs and heterotrophs

Autotrophs

“Self” “Feed”

• plants, algae, some bacteria

• Chemosynthesis and photosynthesis

Heterotrophs

“Other/different” “feed”

• eukaryotes, animals

Photoautotrophs

Convert sunlight energy into G3P (precursor to glucose)

Heterotrophs

Hydrolyzed ingested polymers of organic molecules into monomers

• dinner of steak and potato’s, protein hydrolyzed to amino acids, etc.

Metabolism more info

Monomers can be further broken down to obtain energy or used to build new macromolecules

• chemical energy in the bonds of polymers and monomers can be converted into ATP

Metabolic pathways

Begins with a specific molecule (reactant) which is altered in a series of steps to result in a product

• biological assembly line, sequence to make controlled steps!

• Takes place in: building proteins/carbs, transporting material, muscle cells require energy to move, etc

• 2 types! Catabolic and anabolic

Anabolic(endergonic energy)

Synthesize and builds large molecules

• requires energy, +G

Catabolic (Exergonic)

Degradative, breaks large molecules

• creates energy, -G

Gibbs free energy

Amount of free energy available to the cell to do work and energy created from breaking chemical bonds

Alpha Gibs

Change in free energy

= G of products- of reactants

• 2 types spontaneous and requires energy(endergonic and exergonic)

• All chemical reactions in the cell are coupled with ATP!

Endergonic reaction

• anabolic

• Uphill reaction’requires energy, no spontaneous

• Products have more potential energy than reactants

Exergonic reactions

Catabolic

• downhill spontaneous

• Produce energy in form of ATP

• -G

• Products have less potential energy than reactants

Activation of energy

• prevents reactions from spiraling out of control (called energy of activation)

• Requires stress to be placed on bonds to make them unstable

• Small inputs of initial energy needed (even exergonic)

Enzyme

A type of protein that catalyze chemical reactions by lowering EA

• doesn’t make a reaction occur that would not normally occur

• Does not add energy and does not change alpha gibs!

• Only changes: lowering the energy activation level!

Enzyme specificity (part of enzyme)

Binds to substrates (reactants)

• active site (lock and keyhole)

• Enzyme is unchanged and not consumed

• Converts substrate to a different product

Used a million times, works as a place to make reactions faster

Enzyme reaction

The process of a chemical reaction turning into a product

Enzyme function

They are proteins

• affected by temp, pH, salt

• High temps and acid/basic pH will denature enzyme structure

• Organisms in cold vs hot have ideal temperatures

Anzyme activation

Activators help enzymes!

• Co-factors help enzymes (dent in enzyme)

• Activator attached itself to co factor

Enzyme inhibitors

Blocks activity

• 2 types; non-competitive and competitive inhibitors

No competitive inhibitors

Bind to enzyme at site remote from active site (allosteric site)

• alters shape and prevents from binding

Competitive inhibitors

Mimics shape of substrate, binds to active site to block it

• Pharmaceutical applications (cancer treatments)

Feedback inhibitation

Type of enzymatic regulation/product acts as a non competitive inhibitor