Photosynthesis and Photosynthesis and Cellular RespirationCellular Respiration

Chapters 8 & 9Chapters 8 & 9

8.1 Energy and Life8.1 Energy and Life

Chemical Energy and ATPChemical Energy and ATP

Where do we get our energy?Where do we get our energy?

Ultimately all energy in living systems needed for Ultimately all energy in living systems needed for metabolism comes from the sun. metabolism comes from the sun.

That energy is transferred first to organic That energy is transferred first to organic compounds (glucose)compounds (glucose) then to energy storing molecules (ATP).then to energy storing molecules (ATP).

One of the most important compounds that One of the most important compounds that cells use to store and release energy is cells use to store and release energy is adenosine triphosphate (ATP).adenosine triphosphate (ATP).

ATP Releases energy when a ATP Releases energy when a phosphate group is removedphosphate group is removed

phosphate removed

Tri = 3

Di = 2

Organisms that use photosynthesis to make organic compounds (food) are called autotrophs. Examples: plants, algae, some bacteria

Organisms that must get energy from food are Organisms that must get energy from food are called heterotrophs.called heterotrophs. Cellular respiration converts the food we eat into Cellular respiration converts the food we eat into

energy (ATP and heat).energy (ATP and heat). ATP delivers energy wherever energy is needed in ATP delivers energy wherever energy is needed in

the cell.the cell.

8.2 Photosynthesis: An Overview8.2 Photosynthesis: An Overview When you eat, you can trace the origin of your When you eat, you can trace the origin of your

food back to the sun. food back to the sun.

Photosynthesis Song

Chlorophyll and ChloroplastsChlorophyll and Chloroplasts

Why do we see leaves as green?Why do we see leaves as green?Pigments, light absorbing substances, Pigments, light absorbing substances, absorb only certain wavelengths of light absorb only certain wavelengths of light and reflect all others.and reflect all others.

Chlorophyll, the primary pigment in Chlorophyll, the primary pigment in plants absorbs red, and blue-violet plants absorbs red, and blue-violet light, and reflects green and some light, and reflects green and some yellow.yellow.

Photosynthesis takes place in the chloroplasts Photosynthesis takes place in the chloroplasts of plant cells.of plant cells.

Chloroplasts contain stacks of thylakoids Chloroplasts contain stacks of thylakoids (grana)(grana)

The fluid within the chloroplast is known as The fluid within the chloroplast is known as the stroma.the stroma.

chloroplast

stroma

grana (thylakoids)

Cytoplasmic Streaming of chloroplasts

Overview of photosynthesis:Overview of photosynthesis: Stage 1:Stage 1: Light Dependent Reactions (energy Light Dependent Reactions (energy

is captured from sunlight)is captured from sunlight) Stage 2:Stage 2: Light Dependent Reaction (electron Light Dependent Reaction (electron

transport chain – light energy converted to transport chain – light energy converted to ATP)ATP)

Stage 3:Stage 3: Light Independent Reaction/Calvin Light Independent Reaction/Calvin Cycle (ATP is used to produce glucose)Cycle (ATP is used to produce glucose)

Photosynthesis equation:Photosynthesis equation:

6CO6CO22 + 6H + 6H22O → CO → C66HH1212OO66 + 6O + 6O22 light

Contains chlorophyll

C6H12O6

granum (stack of thylakoids)

thylakoid

sunlight

1 six-carbon sugar

6H2O

6CO2

6O2

chloroplastchloroplast

energy

stroma (fluid outside the thylakoids)

Calvin Cycle/light-dependentreactions (stroma)

Review QuestionsReview Questions

Describe the importance of photosynthesis to Describe the importance of photosynthesis to all forms of life.all forms of life.

Describe the role of light, and chlorophyll in Describe the role of light, and chlorophyll in photosynthesis?photosynthesis?

How does ATP store and release energy?How does ATP store and release energy?

Factors Affecting Photosynthesis (8.3) Factors Affecting Photosynthesis (8.3) Light Light The rate of photosynthesis increases as light The rate of photosynthesis increases as light

intensity increases until all the pigments are intensity increases until all the pigments are being used.being used.

The reactions cannot increase beyond this The reactions cannot increase beyond this pointpoint

TemperatureTemperature Temperatures too high or too low can affect Temperatures too high or too low can affect

the enzymes assisting the chemical reactionsthe enzymes assisting the chemical reactions

WaterWater A shortage of water can slow or even stop A shortage of water can slow or even stop

photosynthesis.photosynthesis. Plants that live in dry conditions have adaptations Plants that live in dry conditions have adaptations

to live in these conditionsto live in these conditions Waxy coatings on their leavesWaxy coatings on their leaves Biochemical adaptations (C4 or CAM)Biochemical adaptations (C4 or CAM)

9.1 Cellular Respiration: An 9.1 Cellular Respiration: An OverviewOverview

Cellular respiration releases the energy in food as Cellular respiration releases the energy in food as ATP when oxygen gas is present.ATP when oxygen gas is present.

Occurs in the mitochondria of a cellOccurs in the mitochondria of a cell

Equation:Equation:

CC66HH1212OO66 + 6O + 6O22 → 6CO → 6CO22 + 6H + 6H22O + energyO + energy

mitochondrion

animal cell

Overview of Cellular RespirationOverview of Cellular RespirationStep 1 – GlycolysisStep 1 – Glycolysis

Begins with sugar (glucose) and makes pyruvic acid Begins with sugar (glucose) and makes pyruvic acid and ATP.and ATP.

Step 2 – KrebStep 2 – Kreb’’s Cycles Cycle When OWhen O2 2 is present, breaks pyruvic acid down is present, breaks pyruvic acid down

releasing COreleasing CO22 and ATP. and ATP. Sends energy to the next stepSends energy to the next step

Step 3 – Electron Transport ChainStep 3 – Electron Transport Chain Uses OUses O22 and energy to make ATP and releases water. and energy to make ATP and releases water.

6H 2O

6CO2

6O2

mitochondrionmitochondrion

Kreb’s Cycle

ATP

ATP

energy

energy

1

2

and

and

and

Glycolysis:Takes place in the cytoplasmStarts with sugar

pyruvic acid

Electron Transport Chain

Comparing Photosynthesis and Comparing Photosynthesis and Cellular RespirationCellular Respiration

Reactions work together:Reactions work together:

PhotosynthesisPhotosynthesis Cellular RespirationCellular Respiration

EnergyEnergy Sun Sun →→ organic organic compoundscompounds

Organic Compounds Organic Compounds → → ATPATP

OxygenOxygen Releases OReleases O22 Uses OUses O22

Carbon Carbon DioxideDioxide

Uses COUses CO22 Releases COReleases CO22

Space Plants Video

Fermentation occurs (anaerobic).Fermentation occurs (anaerobic). Without OWithout O22, releases energy from food producing , releases energy from food producing

ATPATP Lactic acid fermentation – causes muscle burnLactic acid fermentation – causes muscle burn Achoholic fermentation – produces ethyl alcohol and Achoholic fermentation – produces ethyl alcohol and

COCO22. Yeast is a common organism which uses this . Yeast is a common organism which uses this

process.process. Used to make foods such as bread, cheese, and yogurtUsed to make foods such as bread, cheese, and yogurt

9.3 Fermentation9.3 FermentationIf oxygen is not present…..If oxygen is not present…..

Review QuestionsReview Questions

In what type of cells does cellular respiration In what type of cells does cellular respiration take place?take place?

What will occur if no oxygen is present?What will occur if no oxygen is present?