Photosynthesis & Photosynthesis & RespirationRespiration

Energy for life processesEnergy for life processes

Energy is the ability to cause matter to Energy is the ability to cause matter to move or to changemove or to change

The ability to do The ability to do workwork Work for a cell includesWork for a cell includes

Growth & repairGrowth & repair Active transportActive transport ReproductionReproduction Synthesis of moleculesSynthesis of molecules Lots of other stuff!!!Lots of other stuff!!!

Type of energyType of energy

Potential energyPotential energy Stored energyStored energy Example: chemical energy in the chemical Example: chemical energy in the chemical

bonds of molecules such as ATP & glucosebonds of molecules such as ATP & glucose Kinetic energyKinetic energy

Energy of motionEnergy of motion Examples: electrical energy in the flow of Examples: electrical energy in the flow of

electrons, muscle contraction, active electrons, muscle contraction, active transportstransports

Biochemical pathwaysBiochemical pathways

A series of reactions in which the product A series of reactions in which the product of one reaction is the reactant of the nextof one reaction is the reactant of the next

Examples: Examples: Photosynthesis: only Photosynthesis: only autotrophsautotrophs are are

capable of thiscapable of this Cellular respiration: Both Cellular respiration: Both autotrophs & autotrophs &

heterotrophsheterotrophs perform this to release energy perform this to release energy to do cellular workto do cellular work

Biochemical pathwaysBiochemical pathways

ThermodynamicsThermodynamics

The study of energy transformationsThe study of energy transformations 11stst law of thermodynamics law of thermodynamics

Energy cannot be created or destroyed, only Energy cannot be created or destroyed, only converted from one form to anotherconverted from one form to another

Photosynthesis converts LIGHT energy to Photosynthesis converts LIGHT energy to CHEMICAL energy contained in the bonds CHEMICAL energy contained in the bonds of moleculesof molecules

Cellular Respiration takes the chemical Cellular Respiration takes the chemical energy stored in the molecules and converts energy stored in the molecules and converts it into kinetic energy to use in cell processesit into kinetic energy to use in cell processes

ATP – the energy ATP – the energy moleculemolecule

AKA: adenosine triphosphateAKA: adenosine triphosphate Monomers:Monomers:

Adenine baseAdenine base Ribose sugarRibose sugar 3 phosphate groups3 phosphate groups

ATPATP

The energy is stored in the bonds The energy is stored in the bonds BETWEEN the phosphate groupsBETWEEN the phosphate groups

ATP/ADP CycleATP/ADP Cycle

We continuously make and break ATP as We continuously make and break ATP as needed: needed: FOR ENERGY!!FOR ENERGY!!

Light energy & the Light energy & the Electromagnetic Electromagnetic Spectrum Spectrum

Wave descriptionWave description

Electromagnetic radiation – form of Electromagnetic radiation – form of energy that exhibits wavelike behavior as energy that exhibits wavelike behavior as it travels through spaceit travels through space

Longer wavelength = lower energyLonger wavelength = lower energy Has the ability to “excite” molecules and Has the ability to “excite” molecules and

move electrons to carry the energymove electrons to carry the energy

EM SpectrumEM Spectrum

All forms of electromagnetic radiationAll forms of electromagnetic radiation Visible light is the portion we will talk Visible light is the portion we will talk

about (although plants absorb other parts about (although plants absorb other parts of the spectrum). This is the part that we of the spectrum). This is the part that we can see.can see.

ROY G BIV is the order of colors from ROY G BIV is the order of colors from low to high energy (so long to short low to high energy (so long to short wavelength (750 nm to 380 nm)wavelength (750 nm to 380 nm)

LightLight When light strikes an object, it is:When light strikes an object, it is:

AbsorbedAbsorbed – then we can NOT see it – then we can NOT see it TransmittedTransmitted – goes through the object so – goes through the object so

we can see it on the other side of the object we can see it on the other side of the object (like stained glass). The object must be (like stained glass). The object must be transparent or translucent (like wax paper) transparent or translucent (like wax paper) for it to do thisfor it to do this

ReflectedReflected – then we CAN see it because it – then we CAN see it because it bounces back to our eyes.bounces back to our eyes.

Color ExamplesColor Examples

When all colors are absorbed – BLACKWhen all colors are absorbed – BLACK When all colors are reflected – WHITEWhen all colors are reflected – WHITE If only one color is reflected – OBJECT If only one color is reflected – OBJECT

APPEARS THAT COLORAPPEARS THAT COLOR Combinations of the 7 basic colors being A/T/R Combinations of the 7 basic colors being A/T/R

provide all the shades of color that we see.provide all the shades of color that we see. IT IS THE PIGMENT MOLECULES THAT ARE IT IS THE PIGMENT MOLECULES THAT ARE

PRESENT THAT REFLECT & ABSORB LIGHT PRESENT THAT REFLECT & ABSORB LIGHT ENERGIES AND THUS PROVIDE AN ENERGIES AND THUS PROVIDE AN OBJECT WITH ITS COLOROBJECT WITH ITS COLOR

PigmentsPigments

PigmentsPigments

Definition: Molecules that absorb energy Definition: Molecules that absorb energy of specific wavelengths.of specific wavelengths. REMEMBER: whatever they absorb, we REMEMBER: whatever they absorb, we

DON’T seeDON’T see

ChlorophyllChlorophyll

Definition: most common pigment for Definition: most common pigment for photosynthesisphotosynthesis

Reflects GREEN so that is the color Reflects GREEN so that is the color energy that we seeenergy that we see

Absorbs all the other color energies si Absorbs all the other color energies si they get used to make glucose & they get used to make glucose & starches for foodstarches for food

Accessory PigmentsAccessory Pigments Definition: pigments that absorb some of Definition: pigments that absorb some of

the color energies that chlorophyll does the color energies that chlorophyll does notnot

Carotenes & xanthophylls REFLECT Carotenes & xanthophylls REFLECT oranges & yellowsoranges & yellows

We see these colors in the fall when We see these colors in the fall when chlorophyll declineschlorophyll declines

Anthocyanins REFLECT reds & purplesAnthocyanins REFLECT reds & purples Tannin (waste product) gives brown color Tannin (waste product) gives brown color

to dying leavesto dying leaves

Some Accessory Some Accessory PigmentsPigments

ChloroplastChloroplast

Type of plastidType of plastid Site of photosynthesisSite of photosynthesis Has 3 major partsHas 3 major parts

Parts of a chloroplastParts of a chloroplast Thylakoid membranes: Thylakoid membranes:

flattened sacs of photosynthetic membraneflattened sacs of photosynthetic membrane Embedded with chlorophyll & other pigmentsEmbedded with chlorophyll & other pigments

Grana (granum)Grana (granum) Stack of thylakoid membranesStack of thylakoid membranes Connected to each otherConnected to each other Organizes pigments into 2 types of Organizes pigments into 2 types of

photosystemsphotosystems Stroma: gel like material surrounding Stroma: gel like material surrounding

granagrana

PhotosynthesisPhotosynthesis

Overview of the processOverview of the process

Plants & SunlightPlants & Sunlight

Autotrophs trap energy from Autotrophs trap energy from sunlight and use it to build sunlight and use it to build carbohydrates.carbohydrates.

Energy from sunlight is trapped Energy from sunlight is trapped by pigments and used to form by pigments and used to form sugars from CO2 and H2Osugars from CO2 and H2O

6CO2 + 6H2O + energy 6CO2 + 6H2O + energy C6H12O6 + 6O2 C6H12O6 + 6O2

A Continuous ProcessA Continuous Process

Light Dependent reactions – happen Light Dependent reactions – happen in the granain the grana

require energy from light and can only require energy from light and can only happen in the presence of lighthappen in the presence of light

light excites the electrons and the water light excites the electrons and the water splits into hydrogen and oxygensplits into hydrogen and oxygen

““photo” part – since it requires lightphoto” part – since it requires light

A Continuous ProcessA Continuous Process

Light Independent reactions or Light Independent reactions or Calvin cycle – happen in the stromaCalvin cycle – happen in the stroma

may occur in dark or lightmay occur in dark or light require products of light reactionsrequire products of light reactions form simple sugars from using CO2 and form simple sugars from using CO2 and

the H from the H2Othe H from the H2O ““synthesis” part – since it puts together the synthesis” part – since it puts together the

simple sugarssimple sugars

Enzymes in Metabolic Enzymes in Metabolic pathwayspathways

Photosynthesis & cellular Photosynthesis & cellular respiration use enzymes to respiration use enzymes to make them happen at the make them happen at the correct speed to maintain life.correct speed to maintain life.

EnzymesEnzymes

Enzymes are biological catalystsEnzymes are biological catalysts

They speed up chemical They speed up chemical reactions by lowering the amount reactions by lowering the amount of activation energy needed by of activation energy needed by weakening the bonds of the weakening the bonds of the substrate to make it easier to substrate to make it easier to break apartbreak apart

Activation EnergyActivation Energy

energy content of energy content of reactants is the same reactants is the same

energy content of energy content of products is the sameproducts is the same

only the activation only the activation energy has been energy has been lowered by the lowered by the catalyst (enzyme)catalyst (enzyme)(protein)(protein)

Enzyme ActionEnzyme Action

Enzymes are highly specific so they only Enzymes are highly specific so they only act on ONE substrateact on ONE substrate

Remember: lactase only acts on lactoseRemember: lactase only acts on lactose

EnzymesEnzymes

The active site is the location on the The active site is the location on the enzyme where the substrates join enzyme where the substrates join together or break aparttogether or break apart

Excesses in temperature & pH can Excesses in temperature & pH can denature the enzyme by breaking the H denature the enzyme by breaking the H bonds which destroys the active site.bonds which destroys the active site.

MitochondriaMitochondria

Mitochondria-3 Major Mitochondria-3 Major partsparts

Smooth outer membraneSmooth outer membrane

Mitochondria - 3 Major Mitochondria - 3 Major partsparts

Folded inner membraneFolded inner membrane Surface areaSurface area is increase by all the is increase by all the

folds (they are called folds (they are called CRISTAECRISTAE)) Lots of SA is important so we can Lots of SA is important so we can

produce lots of ATP !!produce lots of ATP !!

Mitochondria – 3 partsMitochondria – 3 parts

MatrixMatrixDense Dense

protein protein solution that solution that surrounds surrounds the cristaethe cristae

Function of MitochondriaFunction of Mitochondria

Site of cellular respirationSite of cellular respiration Powerhouse of the cellPowerhouse of the cell Continues the breakdown of Continues the breakdown of

glucose that starts in the glucose that starts in the cytoplasmcytoplasm

Structure determines Structure determines FunctionFunction

The # of mitochondria in a cell is The # of mitochondria in a cell is determined by its functiondetermined by its function

REMEMBER: structure determines REMEMBER: structure determines functionfunction

A liver cell will have ~1000 mitoA liver cell will have ~1000 mito While a muscle cell will have ~10,000 While a muscle cell will have ~10,000

mitomito

Liver vs. MuscleLiver vs. MuscleOn left: liver cell

On right: skeletal muscle cell – note # of pink mitochondria compared to liver cell

Cellular Respiration Cellular Respiration OverviewOverview

CC66HH1212OO66 + 6O + 6O22 -----> 6CO -----> 6CO22 + 6H + 6H220 + 0 +

energy (heat and ATP)energy (heat and ATP) Definition: series of reactions Definition: series of reactions

resulting in a controlled release of resulting in a controlled release of energy from organic moleculesenergy from organic molecules Most often glucoseMost often glucose The energy in one molecule of glucose The energy in one molecule of glucose

may be used to produce 36 ATPmay be used to produce 36 ATP

Series of ReactionsSeries of Reactions

GlycolysisGlycolysis Takes place in cytoplasm of EVERY type of Takes place in cytoplasm of EVERY type of

cellcell Anaerobic (no oxygen required)Anaerobic (no oxygen required)

Krebs cycle takes place in the matrixKrebs cycle takes place in the matrix Electron transport chain takes place in Electron transport chain takes place in

the cristaethe cristae

ChoicesChoices After glycolysis:After glycolysis:

If no oxygen is available in the cell, If no oxygen is available in the cell, fermentation (anaerobic respiration) will take fermentation (anaerobic respiration) will take place.place. Alcoholic fermentationAlcoholic fermentation Lactic acid fermentationLactic acid fermentation If oxygen is available in the cell, aerobic respiration If oxygen is available in the cell, aerobic respiration

takes placetakes place Krebs cycle and electron transport chainKrebs cycle and electron transport chain

Alcoholic FermentationAlcoholic Fermentation

alcoholic fermentation:alcoholic fermentation: end products are ethyl alcohol and carbon end products are ethyl alcohol and carbon

dioxide (COdioxide (CO22))

occurs in bacteria and yeasts – used to occurs in bacteria and yeasts – used to produce bread, wine, beerproduce bread, wine, beer

Lactic Acid FermentationLactic Acid Fermentation

end product is lactic acidend product is lactic acid occurs in bacteria, plants, and most occurs in bacteria, plants, and most

animalsanimals used to make yogurt, cheese, soy sauce, used to make yogurt, cheese, soy sauce,

sourdough bread, and chocolatesourdough bread, and chocolate

Lactic Acid FermentationLactic Acid Fermentation

Muscle cells during strenuous exercise Muscle cells during strenuous exercise cannot get enough ocygen delivered so cannot get enough ocygen delivered so energy comes from pyruvic acid breaking energy comes from pyruvic acid breaking down into lactic acid – this is what down into lactic acid – this is what causes sore musclescauses sore muscles Getting oxygen back into the muscle so the Getting oxygen back into the muscle so the

lactic acid can be broken down is the “cure”lactic acid can be broken down is the “cure”

See ChartSee Chart

Overview of cellular respiration Overview of cellular respiration reactionsreactions