metabolism - chapter 12

PHR 3200

energy coupling

• when energy is released from one reaction is used to power another reaction that requires energy

• How ATP drives unfavorable reactions and ATP synthesize

Electron transfer

the donating and accepting of electrons by NAD+ and FAD during nutrient oxidation

ATP

• major energy carried in cells

• broken down to ADP and AMP through hydrolysis

ATP hydrolysis

• breaks down ATP

• exergonic reaction

• the products are more stable

  • less electronegative repulsion

  • resonance

exergonic reaction

• more energetically favored and stable

• delta G less than 0

• spontaneous

• product has lower free energy

endogonic

• less energetically favored and stable

• delta G is more than 0

• non spontaneous

• product has more free energy

Oxidation

the loss of electrons

reduction

the gain of electrons

NAD

• nicotinamide adenine dinucleotide

• NAD+

  • oxidized form

• NADH

  • reduced form

FAD

• flavin adenine dinucleotide

• FAD

  • oxidized form

• FADH2

  • reduced form

coenzymes

• nonpolar organic molecules needed to start enzyme reactions

Vitamin B

• precursor of coenzymes

• Vitamin B2 (riboflavin)

  • FAD/FMN

  • used for electron transfer

• Vitamin B3 (Niacin)

  • NAD+/NADP+

  • used for electron transfer

metabolism

• cells capture energy from nutrients and use it to make ATP

• network of chemical reactions

shared intermediates

• connects metabolic pathways

  • glyceraldehyde - 3- phosphate

  • Acetyl CoA

catabolism

• breaks down nutrients into smaller molecules

• release energy (ATP)

• Net delta G is always negative

anabolism

• synthesize molecules

• builds molecules

• uses ATP (energy)

• Net delta G is always negative

ATP + H2O → ADP + Pi

delta G = -30.5 kJ/mol

ATP + H2O → AMP + PPi

delta G = -45.6 kJ/mol

PPi + H2O → 2 Pi

delta G = - 19 kJ/mol