HonorsHonorsBiologyBiologyCh. 8Ch. 8

HonorsHonorsBiologyBiologyCh. 8Ch. 8

Cellular

EnergyCellular

Energy

CELL

Nucleus

Cytoplasm

Outer membrane and cell surface

I. How Organisms Obtain Energy

I. How Organisms Obtain Energy- Cells are miniature factories where

thousands of reactions using energy occur constantly.

A.Transformation of EnergyA.Transformation of Energy1.First Law of Thermodynamics:

- Energy cannot be created or destroyed,but can be transformed and transferred.

Chemicalenergy

2. Second Law of Thermodynamics:

2. Second Law of Thermodynamics:- When energy is transformed, some

energy is lost as heat.

Heat

CO2

H2O+

3.All Organisms Use Energy

3.All Organisms Use Energya. Autotrophs

- organisms that make their own food- photosynthesis- producers

b. Heterotrophsb. Heterotrophs- organisms that obtain energy from

other organisms- consumers

B. MetabolismB. Metabolism- all the chemical reactions in a cell

1.Catabolic Pathways:- break down large molecules into smaller molecules releasing energy- cellular respiration

2.Anabolic Pathways:- build up larger molecules from small

molecules using energy- photosynthesis

P

Adenosine triphosphate (ATP)

H2O

+ Energy

Inorganic phosphate Adenosine diphosphate (ADP)

PP

P PP i

C. ATPC. ATP- adenosine triphosphate- energy transfer molecule- provides energy for cellular functions

Light Energy

ECOSYSTEM

CO2 + H2O

Photosynthesisin chloroplasts

Cellular respiration

in mitochondria

Organicmolecules

+ O2

ATP

powers most cellular work

Heat Energy

Energy Flow and Chemical Recycling in

Ecosystems

Energy Flow and Chemical Recycling in

Ecosystems

II.Photosynthesis II.Photosynthesis - light energy is converted to chemical energy

A. Chloroplasts- organelle of photosynthesis

B. Photosynthetic Pigments B. Photosynthetic Pigments - Pigments are substances that

absorb light energy

Gammarays X-rays UV Infrared

Micro-waves

Radiowaves

10–5 nm 10–3 nm 1 nm 103 nm 106 nm1 m

106 nm 103 m

380 450 500 550 600 650 700 750 nm

Visible light

Shorter wavelength

Higher energy

Longer wavelength

Lower energy

- chlorophyll absorbs violet-blue and red light

- Chlorophyll a is the primary photosynthetic pigment.

Ab

sorp

tion

of

lig

ht

by

ch

loro

pla

st

pig

men

ts

400 500 600 700

Chlorophyll a

Chlorophyll b

Carotenoids

Wavelength of light (nm)

- Chlorophyll b and carotenoids are accessory pigments.

- Chlorophyll b and carotenoids are accessory pigments.

Phycoerythrin is found in red algaePhycoerythrin is found in red algae

Phycocyanin is found in blue-green algae

Phycocyanin is found in blue-green algae

Chlorophyll a, Chlorophyll b, and β - Carotene are found in plants.

Chlorophyll a, Chlorophyll b, and β - Carotene are found in plants.

Chlorophyll bChlorophyll bChlorophyll bChlorophyll bChlorophyll aChlorophyll aChlorophyll aChlorophyll a XanthophyXanthophyllll

XanthophyXanthophyllll

ββ --

CaroteneCaroteneββ --

CaroteneCarotene

Photosynthetic Pigments Found in

Spinach leaves

Photosynthetic Pigments Found in

Spinach leaves

Molecular Structure of Cellulose

Molecular Structure of Cellulose

C. Light Reactions C. Light Reactions - Light energy is used to produce

ATP and NADPH for the Calvin Cycle.

O2

CO2H2O

Light

Light reactions Calvin cycle

NADP+

ADP

ATP

NADPH

+ P 1

RuBP 3-Phosphoglycerate

Amino acidsFatty acids

Starch(storage)

Glucose

G3P

Photosystem IIElectron transport chain

Photosystem I

Chloroplast

STROMA(Low H+ concentration)

Photosystem IICytochrome

complex

H2O O21⁄2

Photosystem ILight

THYLAKOID SPACE(High H+ concentration)

STROMA(Low H+ concentration)

Thylakoidmembrane

ATPsynthase

PqPc

Fd

NADP+

reductase

NADPH + H+

NADP+ + 2H+

ToCalvincycle

ADP

PATP

H+

2 H++2 H+

2 H+

- Light energy is used to produce ATP and NADPH for the Calvin Cycle.

C. Light Reactions C. Light Reactions

P700

+

Photosystem II

e

Primary acceptor

2 H+

1⁄2

H2O

e

e

En

erg

y o

f e

lec

tro

ns

Pq

Cytochromecomplex

Pc

ATP

Electron transport chain

Primary acceptor

e

Photosystem I

LightLight

Fd

Electron

Transportchain

NADP+

reductaseNADPH

NADP+

+ 2 H+

+ H+

P680

O2

e

e

1. Light absorbed by Photosystem II

1. Light absorbed by Photosystem II - Water molecules are split, oxygen

released.- Electron becomes ‘excited’ and enters

electron transport chain.

2. The Electron Transport Chain 2. The Electron Transport Chain

- Energy from electrons ‘pumps’ H+ into thylakoid space as it passes along the

electron transport chain.

P700

+

Photosystem II

e

Primary acceptor

2 H+

1⁄2

H2O

e

e

En

erg

y o

f e

lec

tro

ns

Pq

Cytochromecomplex

Pc

ATP

Electron transport chain

Primary acceptor

e

Photosystem I

LightLight

Fd

Electron

Transportchain

NADP+

reductaseNADPH

NADP+

+ 2 H+

+ H+

P680

O2

e

e

3. More Light Absorbed by

Photosystem I3. More Light Absorbed by

Photosystem I

- Electron becomes ‘re-excited’.- NADPH (an electron carrier and energy

transport molecule) is formed.

P700

+

Photosystem II

e

Primary acceptor

2 H+

1⁄2

H2O

e

e

En

erg

y o

f e

lec

tro

ns

Pq

Cytochromecomplex

Pc

ATP

Electron transport chain

Primary acceptor

e

Photosystem I

LightLight

Fd

Electron

Transportchain

NADP+

reductaseNADPH

NADP+

+ 2 H+

+ H+

P680

O2

e

e

STROMA(Low H+ concentration)

Photosystem IICytochrome

complex

H2O O21⁄2

Photosystem ILight

THYLAKOID SPACE(High H+ concentration)

STROMA(Low H+ concentration)

Thylakoidmembrane

ATPsynthase

PqPc

Fd

NADP+

reductase

NADPH + H+

NADP+ + 2H+

ToCalvincycle

ADP

PATP

H+

2 H++2 H+

2 H+

4. Chemiosmosis 4. Chemiosmosis - Hydrogen ions (protons) move down

their concentration gradient out of the thylakoid space.

5. ATP Synthase 5. ATP Synthase

- ATP synthesized by ATP synthase as hydrogen ions pass out of the thylakoid space.

STROMA

THYLAKOID SPACE

H+

H+

H+

H+

H+

H+ H+

H+

P i

+

ADP

ATP

A rotor within the membrane spins clockwise whenH+ flows pastit down the H+

gradient.A stator anchoredin the membraneholds the knobstationary.

A rod (or “stalk”)extending into the knob alsospins, activatingcatalytic sites inthe knob.

Three catalytic sites in the stationary knobjoin inorganic Phosphate to ADPto make ATP.

D.Calvin Cycle D.Calvin Cycle - Glucose produced with energy

from ATP and NADPH from the light reactions.

1. Carbon Fixation 1. Carbon Fixation

- 6 CO2 are joined to 6 5-C molecules of RuBP to form 12 3-C molecules of PGA.

The Calvin Cycle

The Calvin Cycle

LightH2O CO2

LIGHTREACTIONS

ATP

NADPH

NADP+

[CH2O] (sugar)

CALVINCYCLE

ADP

(Entering oneat a time)CO2

3

Phase 1: Carbon fixation

Rubisco

Short-livedintermediate

3 P P

3 P P

Ribulose bisphosphate(RuBP)

P

3-Phosphoglycerate6 ATP

6 ADP

Input

CALVINCYCLE

O2

6

2. G3P Produced 2. G3P Produced

- Energy from 12 ATP and 12 NADPH is used to produce 12 G3P (glyceraldehyde 3-phosphate) molecules.

- 2 G3P molecules are used to make glucose.

(Entering oneat a time)CO2

3

Phase 1: Carbon fixation

Rubisco

Short-livedintermediate

3 P P

3 P P

Ribulose bisphosphate(RuBP)

P

3-Phosphoglycerate

P6 P

1,3-Bisphosphoglycerate

6 NADPH

6 NADP+

6 P i

P6

Glyceraldehyde-3-phosphate(G3P)

Phase 2:Reduction

6 ATP

CALVINCYCLE

P1

G3P(a sugar)Output

Glucose andother organiccompounds

6 ADP

InputLightH2O CO2

LIGHTREACTIONS

ATP

NADP+

[CH2O] (sugar)

CALVINCYCLE

NADPH

ADP

O2

6

The Calvin Cycle

The Calvin Cycle

3. Calvin Cycle Completed 3. Calvin Cycle Completed

- 6 RuBP molecules produced from 10 G3P molecules to complete the Calvin Cycle.

(Entering oneat a time)CO2

3

Phase 1: Carbon fixation

Rubisco

Short-livedintermediate

3 P P

3 P P

Ribulose bisphosphate(RuBP)

P

3-Phosphoglycerate

P6 P

1,3-Bisphosphoglycerate

6 NADPH

6 NADP+

6 P i

P6

Glyceraldehyde-3-phosphate(G3P)

Phase 2:Reduction

6 ATP

3 ATP

3 ADP CALVINCYCLE

P5

Phase 3:Regeneration ofthe CO2 acceptor(RuBP)

P1

G3P(a sugar)Output

Glucose andother organiccompounds

G3P

6 ADP

LightH2O CO2

LIGHTREACTIONS

NADPH

NADP+

[CH2O] (sugar)

CALVINCYCLE

Input

ATP

ADP

O2

6

The Calvin Cycle

The Calvin Cycle

Alternative Photosynthesis Pathways:

C4 and CAMAlternative Photosynthesis Pathways:

C4 and CAM

Organic acidsrelease CO2 toCalvin cycle

Spatial separation of steps. In C4 plants, carbon fixation and the Calvin cycle occur in different types of cells.

Temporal separation of steps. In CAM plants, carbon fixation and the Calvin cycle occur in the same cells at different times.

PineappleSugarcane

Bundle-sheath

cell

Mesophyll Cell

Organic acid

CALVINCYCLE

Sugar

CO2 CO2

Organic acid

CALVINCYCLE

Sugar

C4 CAM

CO2 incorporatedinto four-carbon

organic acids(carbon fixation)

Night

Day

1

2 Organic acidsrelease CO2 toCalvin cycle

CO2

C4

Photosynthesis

C4

Photosynthesis

CAM Photosynthe

sis

CAM Photosynthe

sis

III. Cellular Respiration III. Cellular Respiration - Organic molecules (glucose) are broken

down to release energy in the form of ATP to do cellular work.

Intermembrane

Space

ATP Synthase

Inner Membrane

Outer MembraneDNA

RibosomeCrista

e

Matrix

Granules

MitochondrionMitochondrion

- Occurs in 2 main parts: glycolysis and aerobic respiration

Electrons

carriedvia

NADH

Glycolysis

Glucose Pyruvate

ATP

Electrons carried via NADH and

FADH2

Kreb’s Cycle

Electron Transportand

Chemiosmosis

ATPATP

MitochondrionAerobic

Respiration

A. Glycolysis A. Glycolysis - splits glucose (6-C) into

pyruvate (3-C) to release energy

- produces 2 ATP and 2 NADH- occurs in the cytoplasm - does not require oxygen

2 ADP + 2 P i 2 ATP

GlycolysisGlucose

2 NAD+ 2 NADH

2 Pyruvate

O–

OC

C O

CH3

ATP

NAD+

2 CO2

3 NAD+

3 NADH

+ 3 H+

ADP + P i

FAD

FADH2

Kreb’sCycle

CoA

CoA Acetyle CoA

NADH+ H+

CoA

CO2

Pyruvate

- completes the energy yielding break down of pyruvate

- produces (for each glucose) 2 ATP, 6 NADH, 2 FADH2, and 3 CO2

- takes place in the matrix of the mitochondrion

B. Krebs Cycle B. Krebs Cycle

Electron Transportand Chemiosmosis

Glycolysis

ATP ATP ATP

H+

H+H+

H+

H+

ATPP i

Protein complexof electron carners

Cyt c

(Carrying electronsfrom food)

NADH+

FADH2

NAD+

FAD+ 2 H+ + 1/2 O2

H2O

ADP +

Electron Transport ChainElectron transport and pumping of H+,

which create an H+ gradient across the membrane

ChemiosmosisATP synthesis powered by the flow of H+ back across the membrane

ATPsynthase

Q

Intermembranespace

Innermitochondrialmembrane

Mitochondrialmatrix

Kreb’sCycle

C. Electron Transport Chain C. Electron Transport Chain - a series of protein molecules embedded in

the inner membrane of the mitochondrion- requires oxygen

- Energy from electrons from NADH and FADH2 pumps H+ ion into the intermembrane space creating a H+ gradient.

Electron Transportand Chemiosmosis

Glycolysis

ATP ATP ATP

H+

H+H+

H+

H+

ATPP i

Protein complexof electron carners

Cyt c

(Carrying electronsfrom food)

NADH+

FADH2

NAD+

FAD+ 2 H+ + 1/2 O2

H2O

ADP +

Electron Transport ChainElectron transport and pumping of H+,

which create an H+ gradient across the membrane

ChemiosmosisATP synthesis powered by the flow of H+ back across the membrane

ATPsynthase

Q

Intermembranespace

Innermitochondrialmembrane

Mitochondrialmatrix

Kreb’sCycle

- At the end of the chain, electrons are passed to oxygen, forming water.

Electron Transportand Chemiosmosis

Glycolysis

ATP ATP ATP

H+

H+H+

H+

H+

ATPP i

Protein complexof electron carners

Cyt c

(Carrying electronsfrom food)

NADH+

FADH2

NAD+

FAD+ 2 H+ + 1/2 O2

H2O

ADP +

Electron Transport ChainElectron transport and pumping of H+,

which create an H+ gradient across the membrane

ChemiosmosisATP synthesis powered by the flow of H+ back across the membrane

ATPsynthase

Q

Intermembranespace

Innermitochondrialmembrane

Mitochondrialmatrix

Kreb’sCycle

D. Chemiosmosis D. Chemiosmosis - H+ ions move down their concentration

gradient out of the intermembrane space.- ATP synthesized by

ATP Synthase as H+ ions pass

out of the intermembrane

space.

MITOCHONDRIAL MATRIX

INTERMEMBRANE SPACE

H+

H+

H+

H+

H+

H+ H+

H+

P i

+ADP

ATP

A rotor within the membrane spins clockwise whenH+ flows pastit down the H+

gradient.

A stator anchoredin the membraneholds the knobstationary.

A rod (or “stalk”)extending into the knob alsospins, activatingcatalytic sites inthe knob.

Three catalytic sites in the stationary knobjoin inorganic Phosphate to ADPto make ATP.

ATP Synthase

ATP Synthase

D. Chemiosmosis D. Chemiosmosis - H+ ions move down their concentration

gradient out of the intermembrane space.- ATP synthesized by

ATP Synthase as H+ ions pass

out of the intermembrane

space.- Produces 32 ATP

ATP Synthase

ATP Synthase

IV. Anaerobic Respiration (Fermentation)

IV. Anaerobic Respiration (Fermentation)- Uses glycolysis to produce ATP in the

absence of O2.

- Regenerates NAD from NADH. - Produces only 2 ATP from glucose.

Glucose

CYTOSOLPyruvate

No O2 present:Fermentation

O2 present: Cellular Respiration

Ethanolor

Lactate

Acetyl CoAMITOCHONDRION

Kreb’scycle

A. Lactic Acid FermentationA. Lactic Acid Fermentation- Occurs when skeletal muscles use up O2

faster than lungs can supply O2.

- Lactic acid produced from pyruvate and NADH converted to NAD.

2 ADP + 2 P i 2 ATP

GlycolysisGlucose

2 NAD+ 2 NADH

2 Lactate

Lactic acid fermentation

O–

C O

C O

CH3O

C O

C OHH

CH3

2 Pyruvate

Usain Bolt

- Also produced by bacteria when processing milk into yogurt and cheese.

B.Alcohol FermentationB.Alcohol Fermentation- Occurs in yeast and some bacteria.- Ethanol and CO2 produced

from pyruvate and NADH converted to NAD.

2 ADP + 2 P i 2 ATP

GlycolysisGlucose

2 NAD+ 2 NADH

2 Pyruvate

2 Acetaldehyde2 Ethanol

Alcohol fermentation

H

H OH

CH3

C

O–

OC

C O

CH3

H

C O

CH3

CO22 +2 H+

How Cells Obtain EnergyA Review of Cellular Respiration and Photosynthesis

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