Global warmingGlobal warmingSince the last ice age, carbon dioxide levels have increased

continually. The increase of carbon dioxide over the last 150 years has been much more dramatic going from 280 parts per million (PPM) to 400 PPM. This has had obvious effects on the global temperature averages as the ten hottest years on record occurred from 1998 to now. The ten hottest years ever were:1. 20102. 20053. 19984. 20135. 20036. 20027. 20068. 20099. 200710. 2004

Cellular EnergeticsCellular Energetics

How cells obtain and use energy How cells obtain and use energy through the processes of through the processes of

photosynthesis and cellular photosynthesis and cellular respirationrespiration

IV. Cellular EnergeticsIV. Cellular Energetics

A.A. Energy - ability to do workEnergy - ability to do work1.1. Cells use an energy-storing compound known as Cells use an energy-storing compound known as

ATP to provide the energy to do workATP to provide the energy to do work2.2. ATP = Adenosine TriphosphateATP = Adenosine Triphosphate

a.a. Energy is stored in the bonds between phosphate Energy is stored in the bonds between phosphate groupsgroups

b.b. Energy is released when bonds are brokenEnergy is released when bonds are brokenc.c. ATP becomes ADP when a phosphate is lostATP becomes ADP when a phosphate is lostd.d. ATP is recyclableATP is recyclablee.e. Cells regenerate ATP through the process of cellular Cells regenerate ATP through the process of cellular

respiration which is reliant on photosynthesisrespiration which is reliant on photosynthesis

CO2

H2O

Glucose

O2

ATP

ECOSYSTEM

Sunlight energy

Photosynthesis in chloroplasts

Cellular respiration in mitochondria

(for cellular work)

Heat energy

3.3. Obtaining energyObtaining energya. Autotrophs – organisms capable of using a source of

energy to produce food molecules from inorganic molecules in the environmenti. Photoautotrophs – capture light energyii. Chemoautotrophs – absorb other inorganic molecules to

produce own food

b. Heterotrophs – organisms that obtain energy from the consuming of other organisms

B. Cellular Respiration1. Autotrophs and heterotrophs must be able to release energy

from the carbohydrates produced during photosynthesis2. During cellular respiration, glucose is broken down in a step-

by-step process to release the energy stored in its bonds3. The energy from the breakdown of glucose is used to

generate ATPs4. Chemical equation

C6H12O6 + 6O2 ----> 6CO2 + 6 H2O + ENERGY (ATP)

5. Occurs in the cytoplasm and the mitochondrion

NADH

NADH FADH2

GLYCOLYSISGlucose Pyruvate CITRIC ACID

CYCLE

OXIDATIVE PHOSPHORYLATION (Electron Transport and Chemiosmosis)

Substrate-level phosphorylation

Oxidative phosphorylation

Mitochondrion

and

High-energy electrons

carried by NADH

ATPATPATP

CO2 CO2

Cytoplasm

Substrate-level phosphorylation

6. Reactionsa. Glycolysis

i. Takes place in the cytoplasmii. The initial splitting of a glucose moleculeiii. Produces two pyruvatesiv. Process requires energy (2 ATP) to break apart glucose and

produces 4 ATPv. Breaking of bonds releases energized electrons which are

accepted by a molecule known as NAD+

vi. NAD+ is converted to NADH to carry electrons to the electron transport chain in the mitochondrion

vii. If oxygen is present, the pyruvates can enter the mitochondrion (aerobic)

viii. If oxygen is absent, the pyruvates will remain in the cytoplasm (anaerobic)

b. Krebs Cyclei. Takes place in the mitochondrionii.Two pyruvates enter the mitochondrion and are further broken

down to release energyiii. As pyruvate is gradually broken down,

carbon dioxide is released as a waste product and released electrons are accepted by more NAD+ and an additional molecule known as FAD

iv. Produces 1 ATP for every cycle (2 ATP total)

c. Electron Transport Chaini. Takes place in the inner mitochondrial membraneii. Energized electrons from the broken bonds of glucose and pyruvate

provide the energy to produce ATPsiii. NADH and FADH2 transfer electrons to an ETC

in the inner mitochondrial membraneiv. Energy from the electrons activates proton

pumps, building a proton concentration gradient across the membranev. Protons pass through ATP synthase, a tranport protein/enzyme that

produces ATPvi. As protons pass through, ADP is converted into

ATPvii. Produces up to 34 ATP

d. Overall process produces a total of 36 – 38 ATP

Intermembrane space

Inner mitochondrial membrane

Mitochondrial matrix

Protein complex

Electron flow

Electron carrier

NADH NAD+

FADH2 FAD

H2OATPADP

ATP synthase

H+ H+ H+

H+

H+H+

H+

H+

H+

H+

H+

H+

H+

H+

P

12

O2

Electron Transport Chain Chemiosmosis

.

OXIDATIVE PHOSPHORYLATION

+ 2

H+

H+

H+

H+

H+

H+ H+ H+ H+

H+

H+

H+

H+

O2

H2OP ATP

NADH NAD+

FADH2 FAD

Rotenone Cyanide, carbon monoxide

Oligomycin

DNP

ATPSynthase

12

2

ADP

Electron Transport Chain Chemiosmosis

7. Fermentation - Breaking down glucose without oxygena. Occurs in the cytoplasmb. Otherwise known as anaerobic respirationc. Begins with glycolysisd. Only produces 2 ATPe. Purpose is to regenerate NAD+f. Two types

i. Lactic acid fermentationA. Pyruvate is converted into

lactic acidB. Occurs in muscle cells

ii. Alcoholic fermentationA. Pyruvate is converted to ethyl

alcoholB. Occurs in yeast cells

C. PhotosynthesisC. Photosynthesis1. Conversion of sunlight energy into chemical energy

stored in the bonds of carbohydrates and other organic molecules

2. Chemical equationlight

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

3. Occurs in the chloroplasta. Thylakoid – photosynthetic membrane diskb. Granum – stack of thylakoidsc. Stroma – space between the thylakoids and the outer

membranes of the chloroplast4. Pigments – substance capable of absorbing and

reflecting light energya. Chlorophylls – primary pigmentb. Carotenoidsc. Xanthophylls

5. 5. Reactionsa. Light reactions

i. Capture of sunlight energy to produce temporary energy-storing compounds (ATP and NADPH)

ii. Occurs in the thylakoidsiii. Light is absorbed by photosystems – clusters of pigment

molecules in the thylakoidsiv. Electrons in pigment molecules are “excited” to higher

energy levels

5.5. ReactionsReactionsa.a. Light reactionsLight reactions

v. “Excited” electrons are passed along a series of membrane proteins known as the electron transport chain (ETC) in the thylakoid membrane

vi. Energy from electrons is used to generate ATPvi. Energy from electrons is used to generate ATP- Energy from the electrons activates proton pumps, building a proton concentration gradient as hydrogen ions (protons) are pumped across the membrane- Protons pass through ATP synthase, a transport protien/enzyme that produces ATP- As protons pass through, ADP is converted into ATP

vii. Electrons are eventually passed to an energy-storing molecule known as NADPH

viii. Water is split to replenish electrons in pigment moleculesviii. Water is split to replenish electrons in pigment moleculesix. As water splits, electrons are donated to chlorophyll and oxygen gas is

released

5.5. ReactionsReactionsb. Dark reactions

i. Otherwise known as the Calvin Cycleii. Energy from the ATP and NADPH produced in the light

reactions is used to produce organic molecules from carbon dioxide

iii. Occurs in the stroma