Metabolism

Basic Concepts and DesignBasic Concepts and Design

Metabolism

What is metabolism?What is metabolism? all the chemical reactions that take place in all the chemical reactions that take place in

cellscells series of energy transformationsseries of energy transformations

Why do living organism require energy?Why do living organism require energy? to synthesize large molecules from small onesto synthesize large molecules from small ones to move substances in and out of cellsto move substances in and out of cells muscle contraction and cell movementmuscle contraction and cell movement

Metabolism

What is the difference between phototrophs and What is the difference between phototrophs and chemotrophs?chemotrophs? phototrophs obtain energy from sunlightphototrophs obtain energy from sunlight chemotrophs obtain energy from breaking chemical chemotrophs obtain energy from breaking chemical

bondsbonds What is the difference between anabolic and catabolic What is the difference between anabolic and catabolic

reactions?reactions? catabolic – fuels degraded to release useful energycatabolic – fuels degraded to release useful energy anabolic – energy used to synthesize biomoleculesanabolic – energy used to synthesize biomolecules

Metabolism

Why are reactions often coupled in metabolic pathways?Why are reactions often coupled in metabolic pathways? to insure that the overall free energy change is negativeto insure that the overall free energy change is negative

a reaction that requires energy may be paired with a reaction that requires energy may be paired with one that releases energyone that releases energy

Glucose 2Lactate G°' = -184.5 kJ mol-1

2ADP + 2Pi 2ATP +2H2O G°' = +61.0 kJ mol-1

Glucose +2ADP + 2Pi

2Lactate +2ATP +2H2O G°' = -123.5 kJ mol-1

Metabolism

What is the role of ATP in cells?What is the role of ATP in cells? donor of free energy in energy requiring donor of free energy in energy requiring

reactionsreactions Why is ATP an energy rich molecule?Why is ATP an energy rich molecule?

Metabolism

What are the factors that contribute to the What are the factors that contribute to the large amount of energy released when ATP large amount of energy released when ATP is hydrolzed?is hydrolzed? resonance stabilizationresonance stabilization electrostatic repulsion electrostatic repulsion ease of hydrationease of hydration

Metabolism

Metabolism

What do we mean by What do we mean by phosphoryl transfer phosphoryl transfer potential?potential? ability to donate a ability to donate a

phosphate groupphosphate group What molecules What molecules

besides ATP can besides ATP can transfer POtransfer PO44 groups? groups?

Metabolism

How is ATP How is ATP regenerated in cells?regenerated in cells?

Metabolism

The oxidation of which of these two molecules The oxidation of which of these two molecules will produce more ATP and why?will produce more ATP and why?

Metabolism

• How do molecules with high phosphoryl How do molecules with high phosphoryl transfer potential couple the oxidation of transfer potential couple the oxidation of carbon to the synthesis of ATP?carbon to the synthesis of ATP? glyceraldehyde-3-POglyceraldehyde-3-PO4 4 + NAD+ NAD++ + HPO + HPO44

1,3 biphosphoglycerate + NADH + H1,3 biphosphoglycerate + NADH + H++

1,3 biphosphoglycerate + ADP 1,3 biphosphoglycerate + ADP 3- 3-phosphoglyceric acid + ATPphosphoglyceric acid + ATP

Metabolism

Metabolism

What is happening at What is happening at each stage of each stage of catabolism?catabolism?

Metabolism

While ATP is an activated carrier of While ATP is an activated carrier of phosphoryl groups, what molecule(s) is phosphoryl groups, what molecule(s) is (are) activated carrier(s) of electrons during (are) activated carrier(s) of electrons during oxidation?oxidation? nicotinamine adenine dinucleotide nicotinamine adenine dinucleotide

(NAD)(NAD) flavin adenine dinucleotide (FAD)flavin adenine dinucleotide (FAD)

Metabolism

Metabolism

Ad

N

CNH2

O

++ H+ + 2e-

Ad

N

CNH2

OH H

NAD+

(oxidized form)NADH

(reduced form)

Metabolism

One H is transferred to NAD with 2 electrons and One H is transferred to NAD with 2 electrons and the other H goes into solution as a proton.the other H goes into solution as a proton.

Metabolism

Metabolism

Metabolism

What activated carrier for electrons is used in most What activated carrier for electrons is used in most biosynthetic reactions or the reaction shown biosynthetic reactions or the reaction shown above?above? NADPHNADPH

Metabolism

Why is coenzyme A an important molecule in Why is coenzyme A an important molecule in metabolism?metabolism? carrier of acyl groupscarrier of acyl groups

Metabolism

Metabolism

While metabolism consists of thousands of While metabolism consists of thousands of reactions, each reaction falls into one of six reactions, each reaction falls into one of six categories.categories.

Oxidation-Reduction Reaction

Ligation Reaction

Isomerization Reaction

Group Transfer Reaction

Hydrolytic reaction

Addition or Removal of Functional Groups

Regulation of Metabolism

What are the three basic ways in which metabolic What are the three basic ways in which metabolic reactions are regulated?reactions are regulated? controlling amount of enzymecontrolling amount of enzyme

influencing rate of transcriptioninfluencing rate of transcription altering catalytic activityaltering catalytic activity

allostericallyallostericallycovalent modificationcovalent modification

controlling accessibility of substratescontrolling accessibility of substrates

Regulation of Metabolism

How do hormones influence metabolism?How do hormones influence metabolism? alteration of enzyme activityalteration of enzyme activity

glucagon and glycogen phosphorylaseglucagon and glycogen phosphorylase What other factors influence metabolism?What other factors influence metabolism?

compartmentalizationcompartmentalization energy status of cellenergy status of cell

Metabolism

What do ATP, NADH, FAD and coenzyme What do ATP, NADH, FAD and coenzyme A have in common and what does this A have in common and what does this indicate about these molecules?indicate about these molecules? adenosine diphosphateadenosine diphosphate evolved from early RNA catalystsevolved from early RNA catalysts