Lecture 2 outline ch 8 9
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Lecture 2 Outline (Ch. 8, 9). Energy Thermodynamics Metabolism and Chemical Reactions V.Cellular Energy - ATP Enzymes & Regulation Cell Respiration Redox Reactions Glycolysis Coenzyme Junction VII. Preparation for next Lecture. Energy. What is Energy?.

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Lecture 2 Outline (Ch. 8, 9)

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Lecture 2 Outline (Ch. 8, 9)

  • Energy

  • Thermodynamics

  • Metabolism and Chemical Reactions

  • V.Cellular Energy - ATP

  • Enzymes & Regulation

  • Cell Respiration

    • Redox Reactions

    • Glycolysis

    • Coenzyme Junction

  • VII. Preparation for next Lecture


Energy

What is Energy?

Where does energy on earth come from originally?

[equivalent of 40 million billion calories per second!]

Types of Energy:

- Kinetic Energy = energy of movement

- Potential = stored energy


Energy

Potential Energy

Kinetic Energy

Thermodynamics – study of energy transformation in a system

Potential energy can be converted to kinetic energy (& vice versa)


Thermodynamics

Laws of Thermodynamics: Explain the characteristics of energy

  • 1st Law:

    • Energy is conserved

      • Energy is not created or destroyed

      • Energy can be converted (Chemical  Heat)

2nd Law:

  • During conversions, amount of useful energy decreases

  • No process is 100% efficient

  • Entropy (measure of disorder) is increased

Energy is converted from moreordered to less ordered forms


Potential vs. Kinetic Energy


Metabolism and Energy

Cells convert molecules chemically using cellular energy.


Metabolism

Metabolism – chemical conversions in an organism

Metabolic reactions: All chemical reactions in organism

  • Anabolic = builds up molecules

Catabolic = breaks down molecules

Two Types of Metabolic Reactions


Chemical Reactions

+

+

Reactants

Products

  • Chemical Reaction:

    • Process that makes and breaks chemical bonds

  • Two Types of Chemical Reactions:

    • 1) Exergonic = releases energy

    • 2) Endergonic = requires energy


Metabolism

  • Metabolic reactions:

    • Chemical reactions in organism

Two Types of Metabolic Reactions:

  • Anabolic = build up

Catabolic = break down

Exergonic = release energy

Endergonic = requires energy


Chemical Reactions

Glucose  CO2 + H20

CO2 + H20 Glucose

-ΔG

+ΔG (or 0)

release energy

intake energy

spontaneous

non-spontaneous

• Exergonic reaction

• Endergonic reaction


Question/Recall: Which has more order? Stores more energy? Polymer or Monomer, Diffused or Concentrated H+? What is relationship between order and energy?


What type of energy is stored in a covalent bond?

A.Kinetic energy

B.Diffused energy

C.Heat energy

D.Potential energy

E. Conventional energy


Cellular Energy - ATP

• ATP = adenosine triphosphate

• ribose, adenine, 3 phosphates

• last (terminal) phosphate - removable

Be able to diagram ATP! 


ATP + H2OADP + Pi

Cellular Energy - ATP

• ATP hydrolyzed to ADP

• Exergonic

• Energy released, used in another reactions (endergonic)


Cellular Energy - ATP

• ATP regenerated

• cells power ATP generation by coupling to exergonic reactions

Like cellular respiration!


ATP Cycle


Making ATP from ADP + Pi is…

  • Exergonic because it releases energy

  • Endergonic because it requires energy

  • Exergonic because it requires energy

  • Endergonic because it releases energy


Chemical Reactions

  • Chemical Reactions:

    • Like home offices – tend toward disorder

  • Endergonic – energy taken in; Exergonic – energy given off

Exergonic

Endergonic


Self-Check


Chemical Reactions

Nucleus

Nucleus

Repel

Activation

Energy

Activation

Energy

Nucleus

Nucleus

Repel

Activation Energy: Energy required to “jumpstart” a chemical

reaction

  • Must overcome repulsion of molecules due to negative

  • charged electrons


Chemical Reactions

  • Exergonic Reaction:

    • Reactants have more energy than products

Activation energy:

Make sugar and O2 molecules collide

sugar + O2

water + CO2

“Downhill” reaction


Respiration (ch. 9) preview

Cellular Respiration Equation:

C6H12O6 + O2 CO2 + H2O

You will need to KNOW this equation.


Chemical Reactions and Enzymes

Enzymes

• lower activation energy only for specific reactions

• cell chooses which reactions proceed!

enzymes:

cannot make rxns go that wouldn’t otherwise

Cannot change endergonic into exergonic rxns

Dospeed up rxns that would occur anyway


Enzymes

• Enzymes – control rate of chemical reaction

• sucrase – enzyme sucrose breakdown

“-ase” enzyme

• sucrase – catalyst

-speed up rxn, but not consumed


Enzymes

• enzyme – specific to substrate

• active site – part of enzyme -substrate

• binding tightens fit – induced fit

• form enzyme-substrate complex

• catalytic part of enzyme: converts reactant(s) to product(s)


Enzymes

• Enzymes lowers EA by:

-template orientation

-stress bonds

• substrate(s) enter

-microenvironment

• enzyme reused

• product(s) formed

• What factors might affect enzyme activity?


Enzymes

• inhibitors:

binds & blocks active site

binds allosteric site – alters conformation

• Drug – blocks HIV enzyme at the active site


If a competitive inhibitor is in an enzyme reaction, can you reverse the inhibition by adding more substrate?

  • Yes

  • No

  • I’m not sure

  • Wait, what’s a competitive inhibitor?


Cellular Respiration

Overall purpose:

• convert food to energy

• animals AND plants

• complementary to photosynthesis


Cellular Respiration:

(Exergonic)

Cellular Respiration

• catabolizes sugars to CO2

• requires O2

• at mitochondrion


Redox Reactions

• as part of chemical reaction, e- are transferred

• e- transfer = basis of REDOX reactions

(reduction) (oxidation)


Redox Reactions

Use “H rule” for reactions in this class

Reactant with more H’s = e donor, will be oxidized

Reactant with more O’s = e acceptor, will be reduced

ZH2 + O2 yields ZO + H2O

• follow the H, e- move with them


Self-Check

Oxygen

ZH2


Redox Reactions

Equation for respiration


Redox Reactions

• transfer of e- to oxygen is stepwise


• glucose NADH ETC O2 (makes H2O)

Redox Reactions

• e- moved by NAD/H (from niacin/vit B3)

• NADH  carry e- (reduced!)

• NAD+  not carrying e- (oxidized!)

Where do e- come from?

Where do e- go?


In this equation is NAD+ to NADH oxidized or reduced?

NAD+ + H+ + 2e-  NADH

  • Reduced, it gained electrons

  • Oxidized, it gained electrons

  • Reduced, it lost electrons

  • Oxidized, it lost electrons


Steps of Respiration

• Steps of respiration:

1. glycolysis

2 CO2

Coenzyme Junction

2. Citric acid cycle

4 CO2

3. ETC

4. Chemiosmosis


Cellular Respiration

• Stages of respiration:

1. Glycolysis – prep carbons


Cellular Respiration

1. Glycolysis

• 1 glucose (6C)2 pyruvate (3C)

• Keep track of:

- inputs

- ATP

- NAD+/NADH

- CO2 and H2O

- outputs

• eukaryotes AND prokaryotes


Glucose

Glucose-6-phosphate

ATP

2

1

ADP

Fructose-6-phosphate

Glucose-6-phosphate

Glycolysis


ATP

Fructose-

1, 6-bisphosphate

ADP

4

5

Glyceraldehyde-

3-phosphate

Dihydroxyacetone

phosphate

Glycolysis


2 ADP

2 ATP

Phosphoenolpyruvate

2

2 ADP

10

2 ATP

Pyruvate

2

Glycolysis

Step not shown


How many NET ATP are produced by glycolysis?

  • one

  • two

  • four

  • six

  • eight


Cellular Respiration

Glycolysis

-inputs:

1 Glucose

2 ATP

-outputs:

2 pyruvate

4 ATP (2 net)

2 NADH

CO2 = none yet

(2 H2O)

Where do the outputs go?


Energy production

Mitochondria

• energy from nutrients  ATP


Cellular Respiration

Coenzyme Junction

• 2 pyruvate (3C) 2 Acetyl CoA (2C)

• pyruvate joins coenzyme A (from vitamin B5)

• 2 carbons lost (as CO2)

• 2 NAD+  NADH


Things To Do After Lecture 2…

  • Reading and Preparation:

  • Re-read today’s lecture, highlight all vocabulary you do not understand, and look up terms.

  • Ch. 8 Self-Quiz: #1-6 (correct answers in back of book)

  • Read chapter 9, focus on material covered in lecture (terms, concepts, and figures!)

  • Skim next lecture.

  • “HOMEWORK” (NOT COLLECTED – but things to think about for studying):

  • Describe the relationship between exergonic/endergonic, catabolic/anabolic, and “uphill”/”downhill” chemical reactions

  • Diagram one molecule of ATP and how ADP is different

  • Cut apart the boxes on the previous sheet – match up three (name, energy balance, basic reaction) for glycolysis and three for the coenzyme junction

  • Place the following molecules in order for when they are used/created during glycolysis: fructose-6-phosphate, glucose, glucose-6-phosphate, pyruvate, glyceraldehyde-3-phosphate


Self-check at homeMatch each Step Name with Energy Balance and Basic Reaction


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