topic 5 energy/metabolism

Energy is

The capacity to do work

Chemical work

Making and breaking of chemical bonds

Transport work

– Moving ions, molecules, and larger particles

– Useful for creating concentration gradients

Mechanical work

– Moving organelles, changing cell shape, beating flagella and cilia

– Contracting muscles

Two classes of energy:

Potential and kinetic

▪Potential energy =

▪Kinetic energy =

= energy of position or stored energy

= energy of motion

Chemical energy form of

Potential energy

Energy stored in molecule’s chemical bonds is

– Released when bonds broken

Glucose broken down through metabolic pathways

through metabolic pathways

Broken down glucose forms

???Which is energy currency of cells

Kinetic energy forms

Electrical and mechanical

Electrical energy (transport work):

Charged particles across plasma

membrane

Mechanical energy:

Exhibited by objects in motion due to applied force

• Concentration gradient exists

across plasma membrane

Decomposition reaction

Initial large molecule broken down into smaller

structures

Synthesis (Combination) reaction

Two or more structures combined to form larger

structure

• Exchange (Displacement) reaction

Groups exchanged between two chemical structures

▪ Has decomposition and synthesis components

Most prevalent chemical reaction in human body?

Exchange (displacement)

Reaction rate

– How quickly chemical

reaction takes place

Free energy

– Potential energy stored in

bonds

Potential energy stored in

bonds

Activation energy

– Initial input of energy to

begin reaction

Initial input of energy to begin reaction

Exergonic reactions

Energy released with net decrease in potential energy

Endergonic reaction

Energy supplied with a net increase in potential energy

N2 + 3 H2  2 NH3 is an example of a(n) _______

reaction.

a. exchange

b. synthesis

c. decomposition

d. replacement

e. hydrolys

Most enzymes are

Globular proteins

Globular proteins

• Unique 3-dimensional structure in protein chain =

– Temporarily forms enzyme-substrate complex

Explain enzyme action

A) Substrates fit into active sites

(b1) Enzyme-substrate complex formed

(b2) Reaction occurs

(c1) Products dissociate

(c2) Enzyme is unaltered

Phosphorylation

addition of a phosphate group

Hydrolysis-dehydration reactions

– Dehydration reactions

– Dehydration reactions

Oxidation Reduction reaction

– Exchange where electrons moved from one chemical structure to another

In oxidation reduction:

Oxidized is__ and reduction is __.

Oxidize: losing electrons

Reduction: gaining electrons

Metabolism

All chemical reactions that take place in an organism

Catabolism

Energy-releasing breakdown

Anabolism

Energy utilitizimg synthesis

Intermediates

Molecules in pathways

Cells regulate their metabolic pathways:

1. Controlling enzyme concentrations

2. Producing modulators that change reaction rate

3. Using different enzymes to catalyze reactions

4. Compartmentalizing enzymes within organelles

5. Maintaining optimum ratio of ATP to ADP

In metabolic pathways, feedback inhibition

Is used for producing modulators that change reaction rate

ATP transfer need

High energy phosphate bond

ATP transferring: Aerobic metabolism (aka cellular respiration):

– One glucose molecule can yield 30-32 ATP

ATP transfer anaerobic

Makes 2 ATP

Catabolic pathways produce ATP

– Glycolysis

– Citric acid cycle

– Electron transport system

Glucose oxidation

–Step-by-step breakdown of glucose with energy release

Glucose energy rich molecules

(many C—C, C—H, C—O bonds)

• C6H12O2 + 6 O2 → 6 CO2 + 6 H2O

Stages of glucose oxidation:

Glycolysis, intermediate, citric acid cycle, electron transport system

Glycolysis is the

Breaking into 2 pyruvate molecules

Glycolysis occurs in __ and does __

cytosol and does not require oxygen

Glycolysis phases

Investment and capture

Investment phase

Uses 2 ATP to turn 6 carboned- glucose into pyruvate (3 carbon sugar)

Capture phase:

The 2 3-carboned molecules are oxidized into 2 ATP and 2 NADH

glycolysis initial substrate is __ and the final product is __

Glucose that is produced into 2 pyruvate, 2ATP, and 2 NADH

Intermediate stage: Catalyzed by pyruvate dehydrogenase

Pyruvate and coenzyme A (CoA) react to form acetyl CoA

Intermediate: – During decarboxylation,

carboxyl group is released from pyruvate as CO2

during intermediate stage, decarboxylation reduces this to __.

– Energy released as NADH formed from

NAD

Intermediate stage must occur __ because

Twice / because two NADH molecules from original glucose molecule need to be converted into acetyl-CoA

Citric Acid Cycle Steps

1. for every glucose, 2 acetyl groups enter the cac

2. Acetyl group transfers its two-carbon group

3. Citrate, a six-carbon group is formed

CAC removes

2 CO2 molecules

In CAC every 1 acetyl group, energy is captured as:

3 NADH molecules

1 FADH2 molecule

1 ATP molecule

Function of electron transport system:

–Electron transfer from NADH and FADH2

Electron transport system uses ets/etc to

Energy used to make ATP

Electron transport system located

Within inner membrane cristae

H+ pump: proteins __

transporting H+ from matrix to outer membrane

▪ Maintains H+ gradient

Electron transport chain is

Series of H+ pumps and electron carriers

is the electron transport chain considered oxididation or redox?

Series of redox reactions

Redox reaction in ETS:

Each protein in ETC accepts electrons

Oxidation reaction in Electron transport system:

Passes electrons to next protein

Electron transport system is endo/exer tonic because:

Exergonic because of oxidative phosphorylation

Oxidative Phosphorylation:

▪Exergonic energy used to phosphorylate ADP to make ATP

Fill out

If insufficient oxygen,

Electron Trans chain:

Cell becomes

Glycolysis will

NAD+ must

Electron Trans chain decreases

Cell becomes dependent on glycolysis and requires NAD+ to continue

Glycolysis will shut down w/o NAD+

NAD+ must be regenerated for glycolysis to continue

During regeneration of NAD+, hydrogen

Transferred from NADH to pyruvate

Lactate=

Pyruvate + H