Enzymes, Cellular Respiration, Fermentation

Kinetic energy

energy of motion

Potential energy

energy of position

Gibbs free energy

amount of energy available to do work

Chemical potential energy

position of electrons relative to positive and negative charges

Molecular potential energy

electron configuration and position

First Law of Thermodynamics

energy cannot be created or destroyed

Enthalpy (H)

difference in heat content

Exothermic reaction

releases heat, less potential energy

Endothermic reaction

takes in heat, more potential energy

Entropy (S)

amount of disorder

Second law of thermodynamics

total entropy always increases in isolated systems

What is the Gibbs Free Energy Formula (G)

delta G = delta H - T delta S

gibbs free reaction is spontaneous if

delta G is less than 0

gibbs free reaction is not spontaneous if

delta G is greater than or equal to 0

How does the change in Gibbs Free Energy G react to temperatures?

High delta G in low temps, Low delta G in high temp

If the concentration of reactants are high then…

reactions proceed more quickly

Energetic Coupling

allows chemical energy released from one reaction to drive another

Reduction

an atom gains an electron and a hydrogen, losing an oxygen

Oxidation

Atom loses an electron and a hydrogen, gains an oxygen

Can NADH and NAD+ be completely oxidized?

yes

What does NADH do

donates electrons, carries electrons, reduces things

Reducing agent

donates an electron

Oxidizing agent

accepts an electron

How many negative charges does ATP have

4

What kind of energy does ATP store

potential energy

What do enzymes do to transition states

stabilize them

What causes ATP to release energy

by hydrolyzing it to ADP

Are enzymes consumed in the reaction?

no

Do enzymatic reactions change gibbs free energy

no

What do enzymes do to activation energy?

lower the required amount

Activation energy

amount of free energy required to reach transition state

Transition state

the intermediate condition

What kind of energy are reaction rates dependent on

kinetic energy

What are the three steps of enzyme catalysis

initiation, transition state facilitation, termination

Initiation of enzyme catalysis

substrates are precisely oriented

Transition state facilitation

substrate and R-groups lower activation energy

termination of enzyme catalysis

reaction products are released

Are enzymes able to be saturated?

yes

what is the rate of catalysis limited by

the amount of substrate present and enzymes available

Cofactors

inorganic ions that reversibly interact with enzymes

Coenzymes

organic molecules that interact with enzymes

Prosthetic groups

non-amino acid atoms that are permanently attached to proteins

Cofactor examples

Zn2+

Coenzyme examples

NADH or FADH2

Prosthetic group example

retinal

What two things affect how enzymes function

temperature and pH

Does high or low temperature increase enzymatic reaction rate

high

Allosteric regulation

a molecule changes an enzymes shape by binding to a location other than the active site

Conformational change

an enzyme changes its shape, induced fit

Feedback inhibition

an enzyme in a metabolic pathway is inhibited by the product of that pathway

Metabolic pathway

a series of reactions catalyzed by a different enzyme

Catabolism

breakdown of large molecules, release energy

Anabolism

synthesis of large molecules, absorbs energy

Linear metabolic pathway

generates a final product different from any reactant

Cyclic metabolic pathway

regenerates the first reaction

What are the 4 steps of cellular respiration?

glycolysis, pyruvate processing, citric acid cycle, electron transport chain

Folds in the mitochondrial membrane

cristae

what is the area between two mitochondrial membranes called

intermembrane space

what is the area enclosed by membranes called

matrix

what is the formula for cellular respiration

C6H12O6 + 6O2 —> 6CO2 + 6 H2O + free energy

What does glucose turn into during cellular respiration

oxidizes to carbon dioxide

what does oxygen turn into during cellular respiration

reduces to water

Anaerobic

no oxygen

Aerobic

oxygen

where does glycolysis occur

cytoplasm

how many chemical reactions are in glycolysis

10

What are the two phases of glycolysis

energy investment and energy payoff

What happens in the energy investment phase of glycolysis?

2 ATP consumed

What happens in the energy payoff phase?

sugar is split into two pyruvates, 2 NAD are reduced to NADH and 4 ATP

What enzyme do high levels of ATP inhibit

phosphofructokinase

What does phosphofructokinase phosphorylate

fructose-6-phosphate turns into fructose-1, 6-biphosphate

What binding sites does phosphofructokinase have

an active and regulatory site

What does ATP act as for phosphofructokinase

an allosteric regulator

What marks the end of glycolysis

two pyruvates

What is pyruvate processing catalyzed by

pyruvate dehydrogenase

Where does pyruvate processing occur

mitochondrial matrix

What does pyruvate turn into during processing?

Pyruvate I turns into acetyl CoA

What are the products of pyruvate processing

acetyl CoA, NADH, CO2

How many carbons are in pyruvate and what happens to them in pyruvate processing?

3 carbons, one is oxidized to CO2

Where does the citric acid cycle occur

mitochondrial matrix

What does acetyl CoA turn into during the citric acid cycle

oxidizes to two molecules of CO2

What does the potential energy in the citric acid cycle do

reduces NAD+ to NADH, reduces FAD to FADH2, phosphorilates GDP to GTP

What is GTP

ATP predecessor

Where does the electron transport chain occur

mitochondrial inner membrane

How many enzyme complexes does the ETC use

4

What donates electrons in ETC

NADH and FADH2

What do enzymes use electron energy for in ETC

pump protons into the intermembrane space

Where do the electrons from NADH and FADH2 go to in ETC

O2

What does ATP synthase do in ETC

allows protons to flow back, using the energy to make ATP

What is the yield from oxidative phosphorylation

10 ATP

What do the electrons in the form of hydrogen do in ETC

react with O2 to make water

Complex IV in ETC

iron-containing heme where CN and CO bind to iron to prevent formation of water

What is recycled in fermentation

NADH

What ferments in animal cells

lactic acid

What does fermentation in yeast, reactant and product

acetaldehyde into ethanol