Living organisms must be able to _______ and _______ ________.

Cells are "________" hundreds of biochemical reactions that collectively accomplish the activities of life.

What are some functions that exist because of metabolic pathways?

1) Harness, Utilize, Energy

2) "Miniture factories"

3) Growth, Movement, Reproduction, Ability to respond to stimuli

Metabolic pathways occur in highly regulated steps 

They are compartmentalized 

Product of one reaction is a product of the next 

Each step is catalyzed by a different enzyme

Can be regulated by a feedback mechanism "Feedback inhibition)

Anabloic Reaction

Creates larger molecules from smaller molecules - Energy is consumed!

Examples: Synthesis of amino acids

Synthesis of proteins

Photosynthesis

Catabolic Reactions

Larger molecules broken down to smaller molecules

Example : Cellular respiration

Energy is released!

What is energy?

What are the two types of energy?

Energy is the capacity to do work

1) Kinetic Energy = Energy in motion

E.g A falling rock

2) Potential Energy = Energy of structure or position

E.g Energy stored in a falling rock, Concentration gradients, and charge imbalances

Potential energy -> Kinetic energy

What is the study of thermodynamics?

Are are the 1st and 2nd laws of thermodynamics?

The study of energy and its transformations

1) First Law : Energy can be transferred, but cannot be created or destroyed

2) Second Law : Every energy transfer or transformation increases the entropy of the universe (entropy = randomness / disorder)

Organisms display ________. How do they do this?

Order. They do this by creating disorder of their surroundings!

Living organisms are an island of low entropy in a sea of increasingly high entropy

What is the free energy equation?

What does G equal?

Derived from H = G + S

G = H - TS

Where G is free energy

H is Enthalpy / Total energy

T is absolute temperature

S is Entropy

Explain Exergonic reactions and Endergonic reactions

Exergonic reactions - Spntaneous, Release free energy

Endergonic reactions - Nonspontaneous, Absorb (require) free energy

Read page 10 lecture 8

Catabolic reactions (Release energy) can have reactions that absorb energy

Negative reactions (Absorb energy) can have reactions that release energy

True

ATP is the energy currency of the cell. Adenosine triphosphate

ATP is very unstable

Requires energy to put phosphate in ADP to make ATP

Look at page 12 for pictures!

How does ATP break down to ADP? 

How does this make energy?

ATP break down in aqueous environments through HYDROLYSIS reactions

ATP + H20 -> ADP + Pi (Phosphate inorganic)

The hydrolysis reaction makes energy because it is CATABOLIC/EXERGONIC

G = -7.3kcal/mol

1) Both ADP and Pi are negatively charged - Repulsion favours hydrolysis

2) Release of terminal phosphate is energetically favoured

3) Release of Pi increases the disorder of the system

What is energy coupling?

What is the energy from the hydroysis of ATP into ADP + Pi used for?

Energy coupling is when one reaction's energy production is used to power another reaction.

The hydrolysis of ATP into ADP + Pi is used for powering endergonic reactions

Phosphorylation requires an enzyme driven catalysis - Enzyme brings ATP close to reactant molecule

Free energy is transferred to reactant molecule via transfer of phosphate group

How do cells generate ATP?

How many ATP are broken and resynthesized in a typical cell?

ATP synthesis is endergonic

-> An endergonic reaction that gets its energy from the breakdown of complex molecules like carbohydrates, fats, proteins

Cell respiration makes energy and gives it to ATP -> ATP is broken down by active transport / cell movement / anabolism removing phosphate group and transferring energy outside -> ADP + Pi, Gets energy back from cell resp -> ATP. (Cycle)

About 10,000,000 ATP are broken down and resynthesized in a typical cell

The law of thermodynamics tell us about the rate of reaction.

True or false?

How can the rate of reaction be affected in a cell?

False

The rate of reaction can be affected in a cell by enzymes

Activation energy - What is it?

Transition state - What is it? Are bonds stable during transition state?

What is a Catalyst? Is an enzyme a catalyst?

Activation energy is the minimum amount of energy to start a reaction.

Bonds are unstable during transition state. Transition state is when molecules are exposed to activation energy to start a reaction

A catalyst is something that speeds up the rate of reaction. Yes, an enzyme IS a catalyst

What are enzymes and how do they work? How do they do it?

Do enzymes alter/change the amount of free energy recieved / made.

Enzymes are protein that catalyze reactions. They do this by lowering the activation energy. They do this by briefly combining with the reactants and releasing them when the reaction is complete

Enzymes do changed the amount of free energy recieved / made.

Are enzymes specific or do they bind to any substrate?

What do the substrate interact with? What happens there?

Is the lock and key method old or new?

Enzymes are specific to certain substrates.

The substrate interacts with the active site of the enzyme, which is also where the catalysis happens.

Lock and key method is old, superceded by induced fit method

1) Enzyme binds with substrate

2) Enzyme catalyzes the breakage of a bond (Breakage since its a catalytic cycle(

3) Enzyme releases the changed substrate

4) Back to step 1)

1) Enzymes bring the two reacting molecules together - two possibilities

a) the molecules reach transition state when they collide

b) the active site brings reactants into orientation for catalysis

2) Expose the reactant to an altered charge environment so that they may favour catalysis

a) Active site may contain ionic groups

3) Enzyme changes the shape of the substrate to mimick the transition state.

When there are only a little bit amounts of enzyme and too many substrate the rate of reaction ___________ because all the enzymes are ____________

Plateus

Saturated

What are Enzyme inhibitors?

List the two types of inhibitions at describe them.

Enzyme inhibitors are non substrate molecules that bind to an enzyme and reduce its activity.

1) Competitive inhibition : Where the inhibitor attaches to the enzyme active site, therefore blocking the substrate. They do this because they are similar in shape to the substrate

2) Non-Competitive inhibition : Where the inhibitor attaches to the allosteric site, changing the enzyme shape and therefore blocking the active site.

What are the two types of enzyme regulation?

1) Allosteric regulation

2) Covalent modification

Allosteric regulation is a reversable binding of a regulatory molecule to the allosteric site

They change the affinity of the enzyme from low affinity (Where substrate does not bind) to high affinity (Where substrate can bind) or high affinity to low affinity.

Allosteric regulation : Low to high

Allosteric inhibition : High to low

Covalent modification is when you covalently modify an enzyme to either stop it from working completely, or to get it from not working to working.

I.e adding a phosphate group to an enzyme or taking a phosphate group out

What two things affect enzyme activity? (other than substrates and other enzymes)

List their effects

1) Temperature

- As temperature increases, the rate of reaction increases, but if its too high the enzymes denature which decreases rate of reaction

2) PH

- Most enzymes are optimized for 7PH

- Some secreted enzymes can work out of 7PH

- PH affects the charged groups of the amino acids of enzymes

Takes 10 milliseconds with phosphatases

Takes 1 trillion years without phoshatases