Microbio Chapter 10: Introduction to Metabolism

Metabolism

total of all chemical reactions in the cell

What is metabolism divided into

Catabolism and Anabolism

Calorie (cal)

energy needed to raise 1g of water up 1 C

Joules (J)

1 cal = 4.184 J

Kilocalorie (kcal)

1000 calories

Exergonic reactions

standard free energy change is negative

reaction proceeds spontaneously

Endergonic reactions

standard free energy change is positive

reaction is not spontaneous

GTP is used in

protein synthesis

CTP is used in

Lipid synthesis

UTP is used in

peptidoglycan synthesis

ATP has a high…

phosphate transfer potential which means that it donates a phosphoryl group

What is substrate level phosphorylation (SLP)

Process in which ATP is made from ADP by adding a phosphoryl group

What happens during Redox

electrons move from a donor to an acceptor

Oxidized reaction…

loses electrons

Reduced reaction…

gains electrons

Standard redox potential (E’0)

• measures the tendency of the donor to lose electrons

  • more negative = better donor

  • more positive = better acceptor

• measured in volts

Redox Rules

1. reduced member of the pair that is more negative donates electrons to the oxidized member of the more positive pair

   1. difference in redox potential the greater amount of energy available

Substance being oxidized

electron donor / reducing agent / reductant

Substance being reduced

electron acceptor / oxidizing agent / oxidant

Nernst equation

DG⁰’    = -n F DE’₀

Faraday’s constant (F)

23 kcal/volt

96.5 kJ/volt

ETC

• First electron carrier = most negative E’0

• ETC is found

  • Eukaryotes: inner mitochondria or chloroplast

  • Prokaryotes: cell membrane

• As e- pass from one carrier to next, a small amount of energy is released at each step

NADH and NADPH

two electrons and one protons

FAD and FMN

two electrons and two protons

flavoproteins

CoQ/ubiquinone

two electrons and two protons

lipid

lipophilic, embedded in the membrane itself

Nonheme iron-rulfur proteins

one electron at a time

ferredoxin

iron is not part of a heme group