Ch 9Cellular Respiration

What is Cellular Respiration?The Big Picture

• Catabolic Pathways and Production of _____– _________________- catabolic process that is a partial

degradation of sugars that occurs without the use of ____________.

– _____________________- catabolic pathway that is the most efficient and prevalent. ______________ is consumed as a reaction with organic fuel. In eukaryotic cells, _________________ is the location.

– Formula of Cell Respiration

ATPFERMENTATION

OXYGENCELLULAR RESPIRATION

OXYGEN

MITOCHONDRION

C6H12O6 + 6 O2 6 CO2 + 6 H2O + ENERGY

– Redox Reactions:• Why do catabolic pathways that decompose glucose and other

organic fuels yield energy?– The relocation of electrons released energy stored in

organic molecules and is used to synthesize ATP.•

Na + Cl Na+ + Cl-

• A redox reaction that relocates electrons (very electronegative) closer to oxygen _____________ chemical energy that can be put to work.

• Example with Cellular Respiration Formula

RELEASES

Pg 162

– Energy Harvest via NAD+ and the Electron Transport chain

• Cellular respiration breaks down ____________ and other fuels in a series of steps that strip electrons from glucose (creating sources of energy).

• For each electron, a hydrogen atom (proton) is present. The hydrogen atoms are not transferred directly to oxygen but pass to an enzyme called ________ (nicotinamide adenine dinucleotide)

• The enzyme __________________ removes a pair of hydrogen atoms (2 e- 2 protons) from the substrate. The enzyme delivers the two electrons along with one proton to its coenzyme, NAD+. The proton is released as an H+ into the surrounding solution.

• Formula

GLUCOSE

NAD+

DEHYDROGENASE

Pg 162

• NAD+ is ______________ to NADH. Each NADH molecule formed during respiration represents stored energy that can be tapped to make ATP when the electrons complete their “________” down an energy gradient from NADH to oxygen

• Respiration uses an ____________________________ to break the fall of electrons to oxygen into several energy-releasing steps.

• Summary: FoodNADH ETC Oxygen

REDUCED

FALLELECTRON TRANSPORT CHAIN

• ______________ (the first metabolic stage of respiration)– Glycolysis harvests chemical energy by oxidizing ___________ to

pyruvate.– Two Phases

• Energy ______________ phase: cell spends ATP– Formula:

• Energy ______________ Phase: ATP is produced by substrate-level ___________________ and NAD+ reduction to NADH by electrons released from oxidation of glucose.

– Formula:

• Net energy yield from glycolysis per glucose is ___ ATP and __ NADH

• Glycolysis releases less than a quarter of the chemical energy stored in glucose while the rest remains in the two molecules of pyruvate.

• Diagram: • Basic overview awesome glycolysis• step by step Glycolysis

GLYCOLYSISGLUCOSE

INVESTMENT2 ATP 2 ADP + 2 P

PAYOFFPHOSPHORYLATION

2 NAD+ + 4 e- + 4 H+ 2 NADH + 2 H+

2 2

Pg 166-167 fig 9.9

• The Citric Acid/ Krebs Cycle- occurs when oxygen is ______________– ______________ enters the mitochondrion via active transport where

the enzymes of the citric acid cycle complete the ______________.– Steps of Citric Acid Cycle (p.169 Figure 9.12)

• 1. Pyruvate is converted to a compound called acetyl coenzyme A or _________________.

– During this step, pyruvate’s carboxyl group which is already fully oxidized is removed and given off as ______ because it has little energy.

– The remaining two-carbon fragment is oxidized forming acetate. An enzyme transfers the extracted electrons to NAD+, storing energy as _________.

– Coenzyme A is attached to acetate by an unstable bond making the acetyl group very reactive. This results in ______________ and is ready for its acetyl group to be oxidized.

PRESENTPYRUVATE

OXIDATION

ACETYL CoA

CO2

NADH

ACETYL CoA

• 2. Acetyl CoA adds its two-carbon acetyl group to oxaloacetate producing citrate

– The next seven steps ______________ the citrate back to oxaloacetate.

• 3. Citrate is converted to its isomer isocitrate by the ______________ of one water molecule and the addition of another.

• 4. Citrate loses a CO2 molecule and its result is ______________, reducing NAD+ to NADH

• 5. Another CO2 is lost, and the result is oxidized, reducing NAD+ to NADH. The remaining molecule is attached to coenzyme A by an ______________ bond.

DECOMPOSE

REMOVAL

OXIDIZED

UNSTABLE

• 6. CoA is displaced by a ______________ group, which is transferred to GDP, forming GTP, and then to ADP, forming ATP (__________-level phosphorylation)

• 7. Two ______________ are transferred to FAD, forming FADH2 and oxidizing succinate.

• 8. Addition of a ______________ molecule rearranges bonds in the substrate.

• 9. The substrate is oxidized, reducing NAD+ to NADH and ______________ oxaloacetate.

– Krebs animation 1– Krebs Cycle

PHOSPHATE

SUBSTRATEHYDROGENS

WATER

REGENERATING

• Electron Transport Chain– The ETC is a collection of molecules embedded in the

____________________ of the mitochondrion. The folding of the inner membrane of the mitochondrion.

– Since the cristae contains many folds, it provides space for ______________ of copies of the chain in each mitochondrion.

– Sequence of electron carriers (p. 171 Figure 9.13)– Electron carriers alternate between ______________ and

oxidized states as they accept and donate electrons. – Each component of the chain becomes reduced when it

accepts electrons from its “uphill” neighbor which is less ________________and returns to its oxidized form as it passes electrons to its “______________,” more electronegative neighbor.

INNER MEMBRANE

THOUSANDS

REDUCED

ELECTRONEGATIVEDOWNHILL

– Steps of the ETC• The first molecule is a ______________ because it has a

prosthetic group called flavin mononucleotide (FMN) • The flavoprotein returns to its oxidized form as it passes

______________ to an iron-sulfur protein (Fe*S). • The iron-sulfur protein then passes electrons to a compound

called ubiquinone. Ubiquinone is ________within the membrane rather than residing in a complex.

• Most of the remaining electron carriers between ubiquinone and oxygen are proteins called ______________.

• Cytochromes have a prosthetic ______ group which has an iron atom that accepts and donates electrons.

– Each of the cytochromes in the ETC has a ______________ electron-carrying heme group.

– FADH2, another reduced product of the citric acid cycle is another source of electrons for the ETC. FADH2 adds its electrons to the ETC at complex II at a ______________ energy level than NADH does.

FLAVOPROTEIN

ELECTRONS

MOBILE

CYTOCHROMESHEME

DIFFERENT

LOWER

– Function of the ETC• The ETC makes no ATP ______________.• The function is to _____ the fall of electrons from food to

oxygen to break a large free energy drop into a series of smaller steps that release energy in ______________ amounts.

– _________________- The Energy Coupling Mechanism • ATP synthase is an ______________ located in the inner

membrane of the mitochondrion.– ATP synthase makes ATP from ADP and inorganic

______________– ATP synthase works like an ion pump in ______________.– Uses energy of an existing ion ______________ to power

ATP synthesis by phosphorylation. – The power source is the proton gradient and therefore is

the difference in ______________ of H+ on opposite sides of the membrane.

DIRECTLYEASE

MANAGEABLE

CHEMIOSMOSISENZYME

PHOSPHATEREVERSE

GRADIENT

CONCENTRATION

• Chemiosmosis: The process where energy is stored in the form of an H+ gradient ______________ a membrane being used to drive cellular work. (Do not confuse with osmosis)

• P 171 Figure 9.14 4 Parts to ATP synthase• How does inner mitochondrial membrane generate and keep

the H+ gradient?– Electron transport chain purpose is to _______ the H+

gradient.– The ETC pumps electrons across the membrane (from the

mitochondrial ________ to the intermembrane space).– H+ has a tendency to move _______ across the membrane

so ions pass through a channel in ATP synthase to drive the phosphorylation of ADP.

– The energy stored in an H+ gradient across a membrane couples the redox reactions of the ETC to ATP synthesis: an example of chemiosmosis.

» This H+ gradient is referred to as ________-motive force: capacity to do work

ACROSS

CREATE

MATRIXBACK

PROTON

• Other examples of chemiosmosis– ______________ use to generate ATP during

photosynthesis (light drives ETC)– ______________ generate H+ gradients across their plasma

membrane, then tap the proton-motive force to make ATP and pump nutrients and waste across the membrane, and to rotate their flagella.

• Electron Transport• ETC and ATP Synthesis• CR Overview (long)• ETC

CHLOROPLASTS

PROKARYOTES

• Total ATP Production by Cellular Respiration– Energy flow: glucose NADH ETCproton motive force

ATP– Three main parts of cell respiration

• Glycolysis (substrate-level phosphorylation): __ ATP, __ pyruvate, __ NADH

• Citric Acid Cycle (_________ Cycle) substrate level phos.: __ ATP, __ NADH, __ FADH2

• Electron Transport chain (oxidative phosphorylation): __ or __ ATP

• Totals: __ or __ ATP

2 2 2KREBS

2 6 2

32 3436 38

• Fermentation– Fermentation consists of glycolysis and reactions that

______________ NAD+ by transferring electrons from NADH to pyruvate or derivative of pyruvate.

– The NAD+ can be reused to oxidize sugar by glycolysis resulting in two (net) ATP.

– Two types of Fermentation• ______________ Fermentation Steps:

– Pyruvate is converted to ethanol (ethyl alcohol) in two steps. The first step releases CO2 from the pyruvate which is converted to the two-carbon compound acetaldehyde.

– In the second step, acetaldehyde is reduced by NADH to ethanol. This regenerates the supply of NAD+ needed to continue glycolysis.

• Examples: :

REGENERATE

ALCOHOLIC

bacteria: yeast, humans use it to brew beer, make wine, and bread.

– ______________ acid fermentation Steps:– Pyruvate is reduced directly to NADH to form lactate as

an end product with no release of CO2. (Lactate is the ionized form of lactic acid)

• Examples of Lactic acid fermentation: – Microbial fermentation produce acetone and methanol– ____________________________ make ATP by lactic

acid fermentation when oxygen is scarce.» Strenuous exercise when sugar catabolism for ATP

production outpaces the muscles supply of oxygen from the blood.

» This build up of lactate causes muscle fatigue and pain.

• fermentation 1• Evolutionary Significance of Glycolysis

– Both ______________ and ______________ use ______________ to generate _____.

LACTIC ACID

HUMAN MUSCLE CELLS

EUKARYOTESPROKARYOTESGLYCOLYSIS ATP

Chapter 10- Photosynthesis• Sunlight: the main source of ____________ on Earth

– ________________: process by which light energy from the sun is captured by ________________and is converted to chemical energy stored in _________ and other organic molecules.

– ________________are “producers”: produce their food from CO2 and other inorganic raw materials obtained from the environment.

• The main source of organic compounds for all ________________ organisms.

• Almost all plants are autotrophs, specifically ___________________since they use light as a source of energy to synthesize organic compounds.

• Examples: p.182 Figure 10.2– ________________are “consumers”: obtain their organic

material by consuming compounds produced by other organisms.

• Almost all heterotrophs are dependent on __________________ for food and oxygen

ENERGYPHOTOSYNTHESIS

CHLOROPLASTSSUGAR

AUTOTROPHS

NONAUTOTROPHIC

PHOTOAUTOTROPHS

HETEROTROPHS

PHOTOAUTOTROPHS

• Introduction to Photosynthesis– Formula (LEARN):

• Plant structure: p. 183 Figure 10.3 6 CO2 + 6 H2O + LIGHT C6H12O6 + 6 O2

– ________________gives a plant or leaf its green color as it is a green ________________located within chloroplasts. It is the light energy ________________by chlorophyll that drives the synthesis of organic molecules

– Chloroplasts are found in the cells of the ________________, the tissue in the interior of a leaf

– Carbon dioxide enters the leaf and oxygen exits by the ________________which are tiny pores.

– An envelope of two membranes encloses the ________________, the dense fluid within the chloroplast.

– The ___________ are a system of interconnected membranous sacs that segregate the stroma from the thylakoid space.

• Thylakoids can be stacked in columns called _____________.• Chlorophyll is located in the thylakoid ________________.

CHLOROPHYLLPIGMENT

ABSORBED

MESOPHYLL

STOMATA

STROMATHYLAKOIDS

GRANAMEMBRANE

– The oxygen released from photosynthesis is due to the splitting of ____ and not _____.

• The _______ is incorporated into sugar and ____ is released as waste.

– Photosynthesis is a _________ process• Water is split, and electrons are transferred along with H+

ions from the __________ to CO2, reducing it to a sugar.

• Since electrons __________ in potential energy as they move from water to sugar, this requires energy which is provided by ___________.

H2O CO2

H O

REDOX

WATERINCREASE

LIGHT

– Photosynthesis is broken up into ____ phases:• The light-________________reactions (photo):

– Solar energy is converted to __________ energy (____ and ______)

– Light absorbed by chlorophyll drives a transfer of electrons and Hydrogen from water to an acceptor called ____________.

– Water is ______ and releases oxygen.– Solar power is used to reduce NADP+ to NADPH by

adding a pair of ________________along with a hydrogen nucleus or H+

– ATP is generated by chemiosmosis by ________________________.

– Two products: NADPH and ATP

2DEPENDENT

CHEMICAL ATPNADPH

NADP+

SPLIT

ELECTRONS

PHOTOPHOSPHORYLATION

• Calvin cycle (synthesis): Light independent reactions (sort of)– _______ from the air is incorporated into organic

molecules already present in chloroplast. This process is called carbon ________________.

– Next, the fixed carbon is reduced to ________________ by the addition of electrons. Reducing power is provided by ________________.

– To convert CO2 to carbohydrate, the Calvin cycle also requires ________________ energy in the form of ATP.

– Dark reactions because it does not require light directly but needs the products of the light reactions.

– Products: Sugar (glyceraldehyde-3-phosphate then ________________)

CO2

FIXATIONCARBOHYDRATE

NADPH

CHEMICAL

GLUCOSE

• Sunlight and the light Spectrum– Light is a form of energy known as electromagnetic energy and

travels in rhythmic _________. • Wavelength: the ________________ between crests of

waves

• Electromagnetic spectrum: the entire spectrum of ________________ ranging in wavelength from _______ a nanometer (gamma rays) to _______ a kilometer (radio waves).

WAVESDISTANCE

RADIATION <>

– ____________ Light: From 380 nm to 750 nm.» ___________: discrete particles that act like objects

with a fixed quantity of energy. » Energy of photons is ________________ related to the

wavelength of the light; shorter wavelength, the ________________ the energy.

» The sun radiates the full spectrum but the atmosphere only ________________ visible light to pass through.

» Visible light drives ________________.

VISIBLEPHOTONS

INVERSELY

GREATER

ALLOWSPHOTOSYNTHESIS

– ______________- substance that absorbs visible light.• Different pigments absorb (and reflect) light of different

________________and cause the absorbed wavelengths to disappear.

• The color we see is the color that is the most ______________ by the pigment. – Example: seeing green or black, or white.

• ____________________- instrument that can measure the ability of a pigment to absorb various wavelengths of light.– It directs beams of light of different wavelengths through

a solution of pigment to measure the ________________ of light transmitted at each wavelength.

– ________________Spectrum- graph plotting a pigment’s absorption v. wavelength.» Pg 187 Figure 10.9

PIGMENT

WAVELENGTHS

REFLECTED

SPECTROPHOTOMETER

FRACTION

ABSORPTION

– Significance: By analyzing absorption spectra of chloroplast pigments, scientists can compare the relative ________________ of different wavelengths for driving photosynthesis. (How do we know which wavelength is most effective?)

– ________________ spectrum- graph plotting the rate of photosynthesis (____ release or ____ consumption) v. wavelength

• ________________- the main photosynthetic pigment– Chlorophyll a v. Chlorophyll b- Chlorophyll b is an

accessory pigment that has a slight structural difference which allows them to absorb slightly different colors (and have different colors).

– ________________- yellow and orange hydrocarbons that absorb violet and blue-green light.

– These can broaden the spectrum of photosynthesis and provide __________________: ability to absorb and rid excessive light energy that would damage chlorophyll or interact with oxygen.

EFFECTIVENESS

ACTIONO2 CO2

CHLOROPHYLL

CAROTENOIDS

PHOTOPROTECTION

– Chlorophyll and Light• When a molecule ________________a photon of light, one

of the molecule’s electrons is elevated to an orbital where it has more potential energy (from ground state to ___________ state).

• A compound absorbs only photons that have specific wavelengths which is why each pigment has its ________________ absorption spectrum.

• The electron ________________ stay in an excited state so will drop to its ground state which releases excess energy as _____________.

• Chlorophyll in isolation will also release light (_____________) as well as heat.

• P. 189 Fig. 10.11• Example: Car roof on a hot day (which is coolest?)

ABSORBS

EXCITED

UNIQUECANNOT

HEAT

FLUORESCENCE

• ________________: Reaction Center associated with Light-Harvesting Complexes

– Photosystems are composed of reaction centers surrounded by a number of light-harvesting complexes that consist of ____________ molecules bound to particular ___________.

– The number and variety of pigment molecules allow a photosystem to harvest light over a ________________ surface of the spectrum.

– Picture:

PHOTOSYSTEM

PIGMENT PROTEINS

LARGER

– Reaction Center- protein complex that includes two ________________chlorophyll a molecules and a molecule called the primary electron acceptor.

• These chlorophyll a molecules, because of their environment enable them to use the energy from light to boost one of their electrons to a ________________ energy level.

• First step of the light reactions: ___________-powered transfer an electron from the special chlorophyll a molecule to the primary electron acceptor (_________ reaction).

– Photosystems convert light energy to chemical energy to be used to ________________ sugar.

– The ________________membrane contains two types of photosystems that cooperate in the light reactions.

• Photosystem II (PSII) [first] (Chlorophyll a- ______) Photosystem I (PSI) (Chlorophyll a- ______)

SPECIAL

HIGHER

SOLAR

REDOX

SYNTHESIZETHYLAKOID

p680p700

• Reactions in the Photosystem- Noncyclic electron flow pg190

– Photon of light hits a ________________ in a light harvesting complex and is moved to other pigment molecules until it reaches a P680 molecule in PS II. It excites one of the two P680 molecules.

– The electron is then ________________by the primary electron acceptor.

– An enzyme splits a water molecule into two electrons, two H+ ions and ½ O2. Electrons are supplied one by one to the ________ replacing an electron ______ to the primary electron acceptor. Oxygen combines with another oxygen to form O2.

– Each excited electron passes from the primary electron acceptor of PS II to PS I by an ________________________________.

PIGMENT

CAPTURED

p680 LOST

ELECTRON TRANSPORT CHAIN

– The exergonic “______” of electrons to a lower energy level provides energy for _____ synthesis.

– At the same time, light energy was ________________by a light harvesting complex to the PS I reaction center, exciting an electron of a P700 molecule. The excited electron is then captured by PS I primary electron acceptor, creating an electron “hole” in P700. Hole is filled by an electron that reaches the bottom of the electron transport chain from _________.

– Excited electrons are passed from PS I’s ________________________________ down a electron transport chain through the protein ________________ (Fd).

– The enzyme NADP+ reductase transfers electrons from Fd to NADP+. Two electrons are required for its ________________ to NADPH.

– Summary: Light reactions use solar power to generate ATP (chemical energy) and NADPH (reducing power) which will fuel the ________________.

– non cyclic- good!

FALLATP

TRANSFERRED

PS II

PRIMARY ELECTRON ACCEPTORFERRODOXIN

REDUCTION

CALVIN CYCLE

• Reactions in the Photosystem- _____________ electron flow– Under certain conditions, photoexcited electrons can take a

cyclic electron flow which uses photosystem ___ but not photosystem ___.

– Electrons ______ back from ferredoxin (Fd) to the cytochromes complex and back from there on to a P700 in the PS I reaction center.

– ATP is ______________.– There is no production of ________________ and no release

of ________________. – Why use cyclic electron flow?

– Noncyclic electron flow generates an ________________ amount of ATP and NADPH but the Calvin cycle uses _________ ATP than NADPH so cyclic electron flow can provide more ATP.

– A rise in NADPH can result in shift to cyclic electron flow which allows ATP to catch up to NADPH (_____________________).

CYCLIC

III

CYCLE

GENERATEDNADPH

OXYGEN

EQUAL

MORE

SUPPLY & DEMAND Cyclic & noncyclic

Links!

• cyclic vs non cyclic no narration• Cyclic & noncyclic• non cyclic- good!• non cyclic light rxn• Light rxn overview

CHLOROPLAST BOTH MITOCHONDRIA

photosystems capture light energy and use it to drive electrons to the top of the transport chain.

Have ETC in membrane proteins pump proteins across membranes

High energy electrons dropped down the transport chain are extracted from organic molecules

chloroplast transform light energy into chemical energy in ATP (and NADPH)

Electrons pass through progressively more electronegative carriers

mitochondria transfer chemical energy from food molecules to ATP (and NADH)

CHLOROPLAST BOTH MITOCHONDRIA

The thylakoid membrane of the chloroplast pumps protons from the stroma into the thylakoid space (interior of the thylakoid), which functions as the H+ reservoir. The thylakoid membrane makes ATP as the hydrogen ions diffuse down their concentration gradient from the thylakoid space back to the stroma

ATP synthase are very similar

The inner membrane of the mitochondrion pumps protons from the mitochondrial matrix out of the intermembrane space, which then serves as a reservoir of hydrogen ions that powers the ATP synthase.

• The Calvin Cycle– Similar to the citric acid cycle in that a starting material is

_________________ after molecules enter and leave the cycle.

– But while the citric acid cycle is catabolic, the Calvin cycle is _________________, building sugar from smaller molecules while consuming energy.

– ______ (glyceraldehyde-3-phosphate) is directly produced from the Calvin Cycle (requires _________ turns of the Calvin Cycle, fixing three molecules of CO2

– Phase 1: _________________• CO2 molecules are fixated one at a time by the enzyme

RuBP carboxylase (_________________), attaching to a five carbon sugar, ribulose biphosphate (_________________).

• This produces a six-carbon _________________so unstable that it immediately splits in half, forming two molecules of 3-phosphoglycerate (for each CO2).

REGENERATED

ANABOLIC

G3P3

CARBON FIXATION

RUBISCORuBP

INTERMEDIATE

– Phase 2: _________________• Each molecule of 3-phosphoglycerate receives an additional

phosphate group from ______, becoming 1, 3-biphosphoglycerate.

• Next, a pair of electrons donated from ___________ reduces 1, 3-biphosphoglycerate to G3P. Specifically, the electrons from NADPH reduces the carboxyl group of 3-phosphoglycerate to the aldehyde group of G3P, which stores more _____________ energy.

• G3P is a sugar—the same three-carbon sugar form in _________________ by the splitting of glucose.

• For every ________ molecules of CO2, there are ______ molecules of G3P. But only ____ molecule of this three-carbon sugar can be counted as a net gain of carbohydrate.

REDUCTION

ATP

NADPH

POTENTIAL

GLYCOLYSISTHREE SIX

ONE

• The cycle began with ___ carbons’ worth of carbohydrate in the form of three molecules of the five-carbon sugar _______.

• Now there are ____ carbons’ worth of carbohydrate in the form of six molecules of G3P. One molecule ______ the cycle to be used by the plant cell, but the other five molecules must be recycled to regenerate the three molecules of RuBP.

15RuBP

18EXITS

– Phase 3: _________________ of the CO2 acceptor (RuBP). • With a series of reactions, the carbon skeletons of five

molecules of G3P are __________ by the last steps of the Calvin Cycle into three molecules of RuBP.

• The cycle spends three more molecules of ATP. The RuBP is now prepared to receive CO2 again, and the cycle continues.

• For the net synthesis of one G3P molecule, the Calvin cycle ______________ a total of 9 molecules of ATP and six molecules of NADPH.

• G3P becomes the _________________ molecule for metabolic pathways for other organic compounds.

• Photosynthesis is an _________________ property of the chloroplast which integrates both stages (neither could _________________ on its own).

REGENERATION

REARRANGED

CONSUMES

STARTING

EMERGENT

EXIST

Calvin Cycle Links

• Calvin Cycle 1• Calvin Cycle step by step• Calvin cycle step by step 2• PS review

• Summarizing Photosynthesis’ Significance– Sugar in chloroplasts supplies entire plant with chemical

energy and carbon skeletons for the _________________of all the major organic molecules of plant cells.

– 50% of organic material made by photosynthesis is consumed as fuel for cellular respiration in the _________________of plant cells.

– Sometimes there is a loss of photosynthetic products to _________________

– Only green cells are autotrophic parts of plant. The rest depends on molecules such as carbohydrates to be transported out of the leaves in the form of _________________.

– Most plants manage to make more organic fuel than they need to use so they can store it in the form of _________________ (chloroplasts).

– Photosynthesis is responsible for the _________________in our atmosphere.

SYNTHESIS

MITOCHONDRIA

PHOTORESPIRATION

SUCROSE

STARCHOXYGEN