AP Biology - Metabolism, enzymes, and cellular respiration unit 2

metabolism

All of the chemical reactions that occur within an organism

metabolic pathways

a series of chemical reaction that either build up complex molecules or break down complex molecules

Catabolic pathways

pathways that release energy by breaking down complex molecules into simpler compounds

Anabolic pathways

pathways that consume energy to build complicated molecules from simpler compounds

Energy

the ability to do work

Kinetic energy

energy associated with motion

Thermal energy

energy associated with the movement of atoms or molecules

Potential energy

stored energy

Chemical energy

potential energy stored in chemical bonds

1st law of thermodynamics

Energy cannot be created or destroyed only transformed or transferred

2nd law of thermodynamics

Every energy transfer or transformation increases the entropy of the universe and during some energy transfer transformations some is unstable and lost as heat

Entropy

measure of disorder

Free energy

used to determine the likelihood of reactions in organisms or if the reaction is energetically favorable

equation of free energy

∆G = ∆H - T∆S

∆G

change in free energy

∆H

change in total energy

T

absolute temperature in K

∆S

change in entropy

Exergonic reactions

release energy, spontaneous, ∆G is less than zero

Endergonic reactions

absorb energy, not spontaneous, ∆G is greater than zero

Exergonic drives what?

Endergonic reactions

What are the three types of work cells can perfrom?

mechanical, transport, chemical

Mechanical work

movement

Transport wok

pumping of substances across membranes

Chemical work

synthesis of complex molecules

ATP

main energy source that cells use for most of their work

Phosporylation

the released phosphate moves to another molecule to give energy

Regeneration of ATP

ADP can be regenerated to ATP via the ATP cycle

Oxidation

loss of electrons

Reduction

gain of electrons

To catalyze

to speed up

Activation energy

the minimum amount of energy required to start a chemical reaction

Enzymes

macromolecules that catalyze reactions by lowering the activation energy

Active site

The part of an enzyme or antibody where the chemical reaction occurs

Substrate

A specific reactant acted upon by an enzyme

Induced fit

The change in shape of the active site of an enzyme so that it binds more snugly to the substrate, induced by entry of the substrate.

Enzyme-substrate complex

enzyme binds to its substrate

Enzyme catabolism

enzyme helps break down complex molecules

Enzyme anabolism

enzyme helps build complex molecules

Does the rate of enzyme activity increase or decrease with an increase in temperature?

Increase up to a certain point due to collision

What happens when an enzyme is outside it's optimal ph?

Hydrogen bonds break denaturing the enzyme

Cofactors

nonprotein enzyme helpers

Two types of cofactors

metals and minerals

Coenzymes

organic cofactors

Example of coenzyme

vitamins

Enzyme inhibitors

reduce the activity of specific enzymes

Competitive inhibitors

reduce enzyme activity by blocking substrates from binding to the active site

non-competitive inhibitor

bind to an area other than active site (allosteric site) which changes the shape of the active site preventing substrate from binding

Allosteric enzymes

two binding sites

Allosteric regulation

molecules bind to an allosteric site which changes the shape and function of the active site

Allosteric activator

binds to allosteric site and increases enzyme activity by opening it or unlocking it

Allosteric inhibitor

substrate binds to allosteric site and stabilizes the enzyme shape so that the active site remains closed

Cooperatvity

is a form of allosteric regulation that can amplify enzyme activity

Feedback inhibtion

sometimes end product of metabolic pathway can act as an inhibitor to an early enzyme in the same pathway

Cristae

folds in the inner membrane of mitochondria

Matrix

cytoplasm inside mitochondria

Equation of cellular respiration

C6H12O6 + 6O2 --> 6CO2 + 6H2O + energy

What is oxidized in cellular respiration

glucose to Co2

What is reduced in cellular respiration

O2 to H20

Electron pathway in CR

glucose to NADH to ETC to oxygen

Where does glycolysis occur

cytoplasm

Inputs of glycolysis

1 glucose

Outputs of glycolysis

2 pyruvate, 2 ATP, 2 NADH

Stage 1 of glycolysis

Energy investment - cell uses ATO to phosphorylate compounds of glucose

Stage 2 of Glycolysis

Energy payoff - energy is produced by substrate level phosphorylation

Inputs of pyruvate oxudation

2 pyruvate

outputs of pyruvate oxidation

2 acetyl CoA, 2 CO2, 2 NADH

pyruvate oxidation

pyruvate is oxidized to acetyl CoA and then acetyl CoA is used make citrate for citric acid cycle

Inputs of citric acid cycle

2 Acetyl CoA

Outputs of citric acid cycle

4 CO2, 6 NADH, 2 FADH2, 2 ATP

Where does the citric acid cycle occur?

mitochondrial matrix

Citric acid cycle...

turns CoA into citrate, release Co2, synthesizes ATP, electrons transferred to NADH and FADH2

Inputs of oxidative phosporylation

10 NADH, 2 FADH2

outputs of oxidative phosphorylation

32 ATP

two parts of oxidative phosphorylation

electron transport chain and chemiosmosis

ETC

a sequence of membrane proteins that shuttle electrons down a series of redox reactions

What does the ETC do?

release energy to make ATP and transfers e- to o2 to make H20

Where is the ETC located?

inner mitochondrial membrane

Biggest function of ETC

create a proton (H+) gradient across the membrane

final electron acceptor of ETC

oxygen

Chemiosmosis

the use of energy in a H+ gradient to drive cellular work

ATP synthase

the enzyme that makes ATP from ADP and P

When H+ binds...

the rotor spins

Anaerobic Respiration

generates ATP using an ETC in the absence of oxygen

Final electron of anaerobic

sulfates or nitrates

Fermentation

generates ATP without an ETC, an extension of glycolosis

2 types of fermentation

alcoholic and lactic acid

Alcohaulic fermentation

pyruvate is converted to ethanol

Lactic acid fermentation

pyruvate is reduced directly by NADH to form lactate

How many ATP is produced in fermentation

2 ATP

When lactate is built up in blood....

it lowers the ph

facultative anaerobes

can live with or without oxygen