Ch. 5 Part 1

Front 1

Catabolism

Back 1

Releases energy by oxidation of molecules

Front 2

Anabolism

Back 2

Uses energy to synthesize macromolecules that make up the cell

Front 3

Metabolism

Back 3

- Catabolism

- Glucose --> CO2 + H2O

- Energy = released by hydrolysis of ATP

- Energy is stored in molecules of ATP

- Amino Acids --> Proteins

- Anabolism

Front 4

Enzymes

Back 4

1. Are biological catalysts

2. Increase rate of reaction by decreasing the activation energy of a reaction

3. Chemical reactions require activation energy

Front 5

Activation Energy

Back 5

Energy required to alter reactants so that product can form

Front 6

Proteins: Enzymatic Reaction

Back 6

1. Substrate binds to active site

2. Enzyme-substrate complex

3. Products leave

4. Becomes Enzyme again

Front 7

Components of a holoenzyme

Back 7

1. Apoenzyme (protein portion), inactive

+ 2. Cofactor (nonprotein), activator

= 3. Holoenzyme (whole enzyme), active

Front 8

Factors Influencing Enzyme Activity

Back 8

1. Temperature

2. pH (most active @ 5.0)

3. Substrate concentration

Front 9

Temperature affecting enzyme activity

Back 9

- Temperature increases rate of chemical reactions; increases kinetic energy of atoms

- Too low temp: reduces freq. with enzyme and reactants collide

- Too high temp: enzyme (protein) denatures = looses activity

Optimal temp for human (bacteria): 35-37 C

Thermophile Archaea: 100-120 C

Front 10

Substate concentration affecting enzyme activity

Back 10

- Increase in substrate concentration increases rate of enzymatic reaction

- High substrate concentration results in saturation (active site of enzyme is at all times occupied with substrate).

- Increase of substrate concentration doesn't increase reaction rate

Front 11

pH affecting enzyme activity

Back 11

- Precise pH req. for folding of protein

- Too high or low pH denatures enzymes, then = inactive

Front 12

Inhibitors

Back 12

1. Competitive inhibitor

2. Noncompetitive

3. Feedback Inhibition

Front 13

Competitive Inhibition

Back 13

- Inhibitor competes with substrate for binding to the active site

- Increase in substrate concentration reverses inhibition

- Some competitive inhibitors bind covalently to amino acid(s) in active site and inactivate enzyme permanently

Front 14

Noncompetitive Inhibitors

Back 14

- Do not bind to active site but other regions in enzyme (allosteric inhibition)

- Inhibitor binds allosteric site

- Cyanide binds iron-containing enzymes

Front 15

Feedback Inhibition

Back 15

- Product of metabolic pathway binds and inhibits first enzyme of metabolic pathway

- Feedback inhibition prevents the synthesis of excess product

Front 16

Oxidation

Back 16

Loss of electrons

Front 17

Reduction

Back 17

Gain of electrons

Front 18

Oxidation reaction = ?

Back 18

Dehydrogenation reaction

Front 19

NAD+ serves as?

Back 19

- Electron (Hydrogen) acceptor

- NADH contains more energy

Front 20

Glucose redox reaction

Back 20

glucose

C6H12O6 + 6O2 ---> 6CO2 + 6 H2O + ATP (cellular energy)

Front 21

ATP (Adenosine Triphosphate)

Back 21

- ATP serves as energy currency in cells

- Primary energy-harvesting and transferring molecule

- Energy released during chemical rxns is harvested and stored in form of ATP, cell uses ATP as energy source to drive biochemical rxn, generated primarily during cellular respiration

Front 22

Phosphorylation

Back 22

Enzymes transfer terminal phosphate-group of ATP to other compounds and thereby prime (activate) the molecules for further reactions

Front 23

Dephosphorylation

Back 23

Enzymes remove phosphate group from molecule and deactivate molecule

Front 24

Generation of ATP

Back 24

1. Substrate level phosphorylation

2. Oxidative phosphorylation

3. Photophosphorylation

Front 25

Substrate level phosphorylation

Back 25

ATP is generated when enzyme transfers high-energy Pi from phosphorylated substrate directly to ADP

Front 26

Oxidative Phosphorylation

Back 26

- Electrons are transferred from organic substrate to electron carrier (NAD+; FAD+)

- Electrons are transferred to terminal electron acceptor oxygen via an electron transport chain (ETC)

- Energy released during electron transport is used to generate ATP

Front 27

Photophosphorylation

Back 27

- Occurs in photosynthetic cells

- Light energy is converted into ATP and NADPH

- ATP and NADPH are used to produce organic molecules from CO2 and H2O