Unit 3- Energy and Metabolism

Enzymes

Biological catalysts(made of protein) that speed up rate of chemical reactions by lowering activation energy required for reaction to occur

Enzymes

Has active site (exposed R groups) where reaction occurs

Enzymes

Can break down substance(Catabolic reaction) or build up substances (anabolic)

Enzymes

Substrate complex is formed

substrate

Is what enzyme acts on

How is rate determined

By collisions between substrate and enzyme

Identify enzyme

Ends in -ase, named after substarte

Enzymes

Specific to substrate; the substrate must be complementary to the surface properties (shape and charge) of the active site (which is made up of R groups with specific chemistry,i.e. hydrophobic)

How enzymes are affected

pH and temperature, increased temperature, increased collison between molecules, too much heat denatures enzymes

Enzyme concentration

More enzyme faster rate, less enzyme slower rate

Substrate Concentration

More substrate faster rate; Vmax is fastest enzyme can work when saturated)

Inhibition-competitive inhibition

Something competes for active site; can be overcome with more substrate

Non competitive inhibition

Attaches at allosteric site and changes shape of enzyme so it is not functional; cannot be overcome with more substrate

Coenzymes

Organic; NAD and vitamin B atc.) and cofactors (inorganic; zinc, magnesium etc.) interact with enzymes to put them into the right structure to do work

Cellular respiration

Makes ATP for cell use; uses glucose and oxygen makes waste products of carbon dioxide and water; occurs in mitochondria; NADH is electron carrier used

Glycolysis

Occurs in cytoplasm; anaerobic

Glycolysis

Rearranges the bonds in glucose molecules, releasing free energy to form ATP from ADP through substrate-level phosphorylation resulting in the production of pyruvate

Kreb’s Cycle

Occurs in mitochondrial matrix

Kreb’s Cycle

Also called the citric acid cycle

Kreb’s Cycle

Occurs twice per molecule of glucose

Kreb’s Cycle

Pyruvate is oxidized further and carbon dioxide is released ; ATP is synthesized from ADP and inorganic phosphate via substrate level phosphorylation and electrons are captured by coenzymes (NAD+ and FAD)

Kreb’s cycle

NADH and FADH2 carry electrons to the electron transport chain

Electron Transport Chain and Chemiosmosis

The electron transport chain captures electrons, pumping H+ ions into the intermembrane space of the mitochondria

Electron Transport Chain and Chemiosmosis

Electrons are accepted by O2 molecule forming H2O

Electron Transport Chain and Chemiosmosis

Concentration of H+ builds up within inner-membrane space lowering the pH and ions rush through ATP synthase into the mitochondrial matrix. Rush of ions “spins” ATP synthase protein, causing ADP and P, to join forming ATP by oxidative and phosphorylation.