What are metabolites?

Chemical intermediates

What are the 2 major purposes of metabolism?

- Obtain usable chemical energy from environment - Make specific molecules that cells need to live and grow

Anabolic pathways __(use/release)___ energy to __(break/build)___ larger molecules and are generally __(oxidative/reductive)____

- Use - Build - Reductive

From where do anabolic pathways get energy from?

From high energy molecule

What does reductive mean?

E- are used to make new bonds

Catabolic pathways __(use/release)___ energy and are generally __(oxidative/reductive)____

- Release - Oxidative

What does oxidative mean?

E- are removed as bonds are broken

What are amphibolic pathways?

Operate in both catabolic and anabolic pathways

What are the 4 dietary macromolecules?

- Nucleic acids - Proteins - Polysaccharides - Triacylglycerol

What are carbs stored as? Where?

Glycogen - In liver (hepatocytes) - In skeletal muscle (myocytes)

What are fatty acids stored as? Where?

Fat (triacylglycerols) - In adipocytes (fat cells)

During catabolism, carbon metabolites become more ____(oxidized/reduced)___

Oxidized

T/F: carbs are more reduced than fat

False, fat needs more oxidation steps to become oxidized

What is typically an end product after catabolism?

Carbon dioxide

Standard vs Actual free energy change

Standard: thermodynamic term Actual: depends on conc of the substrates

What is the pH, Conc, Temp, Pressure, H2O conc at the biochemical standard state?

pH: 7 [S]/[P]: 1M Temp: 25 deg cel Pressure: 1 atm [H2O]: 55M

A rxn will only process forward when ΔG` is _____

Negative

Is there a standard state for the equilibrium constant?

No - Keq

If ΔG` > 0

Rxn will NOT occur forward

If ΔG` < 0

Rxn WILL occur

If ΔG` << 0? Regulated?

Irreversible - Regulated

If ΔG` ~ 0? Regulated?

- Reversible - No regulation

What is "steady state"?

Ex Water coming in = Water coming out

T/F: Conc of metabolites change once pathways begin

False

What are the characteristics of the Rate limiting step?

- Irreversible - Regulated

What is product inhibition?

Enzyme inhibited by product of rxn

What is feedback inhibition?

Enzyme is inhibited by metabolite further down pathway

What is Feed forward activation?

Enzyme is activated by metabolite upstream

What is reciprocal regulation?

Opposing pathways catalyze reverse of another pathway - regulated so they dont go at the same time

What ΔG are high energy intermediates associated with?

>25kj/mol released

What are the 3 types of high energy intermediates?

E- carriers, Nucleoside triphosphates, thioesters

What are the electron carriers?

NADP, NADPH, FADH2, FMNH2 - e- acceptors

What are nucleoside triphosphates?

ATP, UTP, GTP - PA bonds are high energy bonds

What type of free energy change are thioesters associated with?

Phosphoanhydride hydrolysis

Are cofactors reduced or oxidized in catabolism?

Reduced

Are cofactors reduced or oxidized in anabolism?

Oxidized

What are the most important e- carriers in metabolism?

NAD+ FAD

What enzyme is used to carry out reoxidation of FADH2 to FAD for citric acid cycle?

Coenzyme Q

What is the ΔG for the hydrolysis of a PA bond?

-32kj/mol

What are the 3 reasons why ATP is a high energy molecule

- Decreased electrostatic repulsion - Resonance stabilization - Solvation effects

T/F: Thioesters have e- delocalization

True

What makes ATP "high energy"?

The PA bonds

By what process is ATP made? Catabolism or anabolism

Catabolism

T/F: free energy changes are additive

True

Can an unfavourable rxn happen when a favourable rxn occurs?

Yes, the overall ΔG must be < 0

What is "Phosphate transfer potential"

Free energies of hydrolysis for phosphate containing compounds