Metabolism

• Metabolism – all the chemical reactions
• Catabolism – larger molecules are broken down to smaller molecules.
• Glucose – CO
2 and water – cellular respiration – energy is released
• Anabolism – larger molecules are synthesized from smaller molecules.
• CO
2
+ water – glucose –photosynthesis
• Energy is used
• Energy released in catabolic reactions is stored in ATP

• ATP – quick source of energy in cells
• Energy carrier molecule
• Synthesis, movement, transport
• ATP ----- ADP + Phosphate + energy
• ADP + phosphate + energy ---- ATP

• Almost all the chemical reactions – enzymes
• Biological catalysts
• Speed up chemical reactions
• Come out of the reaction unchanged
• Absence enzymes – chemical reactions take place slow – cells cannot survive
• Specific for its substrate
• Substrate – substance with which the enzyme reacts.

• Bring molecules together
• Weaken bonds in a molecule – breaks down

denaturation
Enzymes are saturated
No free enzymes to interact
With the excess substrate.

• Enzyme inhibitors – competitive, noncompetitive
• Compete with the substrate for the active site.
• Sulfanilamide – synthetic drug – UTI
• Para aminobenzoic acid (PABA) ------ folic acid
• Enzyme
• Drug takes the place of PABA on the enzyme
• Inactivates the enzyme

• Noncompetitive inhibitor binds to the allosteric site on the enzyme
• Allosteric site – site other than the active site
• Shape of the active site is changed
• Enzyme is inactivated
• Cyanide

• Glucose is catabolized
• Oxidation reduction reactions
• Loss of electron or hydrogen atom – oxidation
• Gain of electron or hydrogen atom – reduction
• Leo says ger

Oxidation reduction reactions are coupled
They take place simultaneously

• Catabolism of glucose – energy (ATP)
• Cellular respiration
• Aerobic respiration
• Anaerobic respiration
• Aerobic respiration – O
2 is used
• 6C
6
H
12
O
6
+6O
2
> 6CO
2
+ 6H
• Glucose – oxidized – CO
2
2
O + energy
• O
2 reduced to water
• Glycolysis, transition reaction
• Krebs cycle, oxidative phosphorylation
(electron transport chain)

Glycolysis
Sugar splitting
Cytosol = liquid
Part of the cytoplasm
Each molec. Glucose
2 pyruvic acid + 2NADH + 4ATP
Cell gains only 2 ATP
Substrate level phosphorylation
Phosphate is added from a substrate to
ADP

Transition reaction
Decarboxylated oxidized matrix of mitochondria each molecule of glucose
2 acetyl CoA + 2NADH + 2 CO2
6NADH + 2 FADH2 + 4CO2 + 2 ATP interact with the electron transport chain located on the inner membrane of mitochondria electron transport chain – inner membrane of mitochondria

Power house – cellular respiration
DNA
70S ribosomes intermembrane space

oxidized flavin mononucleotide FMN chemiosmosis ubiquinone Q oxidation of ETC cytochrome cyt phosphorylation of ADP

summary
NADH – 3ATP
10 NADH
– 30 ATP
FADH2 – 2 ATP
2 FADH2 – 4 ATP

• Similar to aerobic respiration
• Final e- acceptor is an inorganic substance other than O2
• Pseudomonas aeruginosa uses nitrate ion as the final e- acceptor

• O2 is not used
• Only glycolysis takes place
• 2ATP are made
• Organic molecule is the final e- acceptor

• Lipids, proteins – used for energy
• Triglyceride  glycerol + 3 fatty acids
• Exoenzyme - lipase
• Glycerol – dihydroxyacetone phosphate
• Goes into glycolysis
• Fatty acid  many units of acetyl CoA
• Goes into Krebs cycle
• Proteins – amino acids – proteases
• AA – intermediates of glycolysis, Krebs cycle

• Plants and algae – chloroplasts
• 6CO
2
+ 6 H
2
O  C
6
H
12
O
6
• Light dependent reactions
+6O
2
• Light independent reactions ( Calvin-
Benson reaction)

sunlight
CO2 + water ---------- glucose
ATP --- energy
Synthesis, transport, movement
Sun is the ultimate source of energy