Chapters 8 & 9 Photosynthesis and Cellular Respiration

Chapters 8 & 9Chapters 8 & 9

Photosynthesis and Cellular Photosynthesis and Cellular RespirationRespiration

I.I. Energy: Energy: the ability to do the ability to do workwork

A.A. Cells work: growth, repair, active Cells work: growth, repair, active transport, and reproductiontransport, and reproduction

B.B. Organisms get energy from foodOrganisms get energy from foodC.C. How do organisms get food?How do organisms get food?

1. Make it1. Make it2. Eat it2. Eat it

II.II. Autotrophs & Autotrophs & HeterotrophsHeterotrophs

A.A. Autotrophs: make their own foodAutotrophs: make their own food

1. Most are photosynthetic1. Most are photosynthetic

-- use sunlight as an use sunlight as an energy sourceenergy source

-- examples: plants examples: plants & algae& algae

2. A few are chemosynthetic2. A few are chemosynthetic

- use inorganic compounds - use inorganic compounds as an energy sourceas an energy source

-- example: bacteria deep in example: bacteria deep in oceanocean

B. Heterotrophs: cannot make B. Heterotrophs: cannot make their own food (also called their own food (also called consumers)consumers)

1. Eat autotrophs or other 1. Eat autotrophs or other heterotrophs heterotrophs

2. Examples: 2. Examples: animals, fungianimals, fungi

III. ATPIII. ATP

A.A. Cells store energy in the form of a Cells store energy in the form of a molecule called adenosine molecule called adenosine triphosphate (ATP)triphosphate (ATP)

B.B. Parts of ATPParts of ATP

1. Adenine – a nucleotide1. Adenine – a nucleotide

2. Ribose – 5 carbon sugar2. Ribose – 5 carbon sugar

3. 3 phosphate groups (PO3. 3 phosphate groups (PO44))

Bonds broken to release energy

Adenosine

-- adenosine+POadenosine+PO44=AMP=AMP

(adenosine monophosphate)(adenosine monophosphate)

-- adenosine+POadenosine+PO44+PO+PO44=ADP=ADP

(adenosine diphosphate)(adenosine diphosphate)

- adenosine+PO- adenosine+PO44+PO+PO44+PO+PO44=ATP=ATP

C.C. ATP CycleATP Cycle

1. Food energy is used to 1. Food energy is used to make ATP in cellular make ATP in cellular respirationrespiration

2. ATP is broken down to 2. ATP is broken down to release energy for the cellrelease energy for the cell

ATP

ADP

Energy for cellFood

energy

IV. PhotosynthesisIV. Photosynthesis

A.A. Photosynthesis occurs in Photosynthesis occurs in chloroplasts (organelles inside chloroplasts (organelles inside plantsplants))

B.B. Overview of PhotosynthesisOverview of Photosynthesis

1. Uses light as the source of 1. Uses light as the source of energyenergy

2. Makes glucose (C2. Makes glucose (C66HH1212OO66))

3. Uses water and carbon 3. Uses water and carbon dioxide as reactantsdioxide as reactants

4. Chlorophyll is the catalyst4. Chlorophyll is the catalyst

5.5. Gives off oxygen as a by-productGives off oxygen as a by-product

6. Equation: 6. Equation:

6CO6CO22 + 6H + 6H2200

CC66HH1212OO66 + 6O + 6O22

C.C. Photosynthetic pigmentsPhotosynthetic pigments1. Chlorophyll: primary 1. Chlorophyll: primary pigment; appears greenpigment; appears green

2.2. Carotenoids: secondary Carotenoids: secondary pigments; can appear pigments; can appear yellow, red, or orangeyellow, red, or orange

D.D. Chloroplast StructureChloroplast Structure

1. Double membrane 1. Double membrane (inner=folded, (inner=folded,

outer=smooth)outer=smooth)

granagrana: stacks of thylakoids: stacks of thylakoids

thylakoidthylakoid: 1 disc: 1 disc

stromastroma: gel-like material : gel-like material between thylakoidsbetween thylakoids

2. 2. Light dependent reactions Light dependent reactions occur in the granaoccur in the grana

3. Light independent reactions 3. Light independent reactions (Calvin Cycle) occur in the (Calvin Cycle) occur in the stromastroma

E.E. Summary of PhotosynthesisSummary of Photosynthesis

1. Light dependent reactions:1. Light dependent reactions: a. a. light causes electrons in light causes electrons in

chlorophyll to become chlorophyll to become excitedexcited

b.b. light energy is also used light energy is also used to split waterto split water

c. c. oxygen is released as a oxygen is released as a by-productby-product

d. d. hydrogen is passed to the hydrogen is passed to the Calvin CycleCalvin Cycle

e.e. ATP is made - this is used ATP is made - this is used as an energy source for as an energy source for the Calvin Cyclethe Calvin Cycle

2. The light independent 2. The light independent reactions reactions (also called the (also called the Calvin Cycle)Calvin Cycle)

a. COa. CO22 from the air combines from the air combines with the hydrogen from the with the hydrogen from the light dependent reactions light dependent reactions to to make sugar (Cmake sugar (C66HH1212OO66))

b. ATP made in light b. ATP made in light dependent reactions is dependent reactions is used as an energy sourceused as an energy source

3. Summary equation:3. Summary equation:

6CO6CO22 + 6H + 6H2200 C C66HH1212OO66 + 6O + 6O22

- - light is required as an energy light is required as an energy sourcesource

- - chlorophyll is required as a chlorophyll is required as a catalystcatalyst

V. Cellular RespirationV. Cellular Respiration

A.A. Respiration occurs in Respiration occurs in mitochondria (organelles in mitochondria (organelles in all all eukaryotic cellseukaryotic cells))

B.B. Overview of RespirationOverview of Respiration

1. Usually uses oxygen1. Usually uses oxygen

2. Breaks down glucose into 2. Breaks down glucose into energy energy

3. Gives off carbon dioxide and 3. Gives off carbon dioxide and water as by-productswater as by-products

4. Equation:4. Equation:

CC66HH1212OO66 + 6O + 6O22

6CO6CO22 + 6H + 6H220 + 0 + energyenergy

C. Steps of RespirationC. Steps of Respiration

1. Glycolysis: glucose is 1. Glycolysis: glucose is converted to pyruvic acidconverted to pyruvic acid a.a. 2 molecules of ATP 2 molecules of ATP

requiredrequired b. b. oxygen not requiredoxygen not required c. c. glucose (6 carbons) is glucose (6 carbons) is broken down into 2 broken down into 2

molecules of pyruvic acid molecules of pyruvic acid (3 (3 carbons)carbons)

d.d. 4 molecules of ATP released4 molecules of ATP released

e. e. An energy-rich molecule An energy-rich molecule called NADH is made – this called NADH is made – this will will be used later to make be used later to make ATPATP

2.2. Aerobic respiration: occurs if Aerobic respiration: occurs if oxygen is presentoxygen is present

a. pyruvic acid is broken down a. pyruvic acid is broken down into acetyl Coenzyme A into acetyl Coenzyme A

b. acetyl Coenzyme A enters b. acetyl Coenzyme A enters the Krebs Cycle the Krebs Cycle

c. In the Krebs Cycle:c. In the Krebs Cycle:

1. CO1. CO22 is released is released2. 2 molecules of ATP are 2. 2 molecules of ATP are

produced produced3. Energy rich molecules of 3. Energy rich molecules of NADH and FADH NADH and FADH22 are are

produced – these will be produced – these will be used later to make ATP used later to make ATP

d. The electron transport chaind. The electron transport chain1. Electrons from NADH and 1. Electrons from NADH and

FADH FADH22 are passed along the are passed along the electron transport chain electron transport chain

2. Energy from these 2. Energy from these electrons is used to make electrons is used to make 32 ATP32 ATP

3. Hydrogen from NADH and 3. Hydrogen from NADH and FADHFADH22 is combined with is combined with oxygen to produce Hoxygen to produce H22OO

3. Anaerobic respiration: occurs 3. Anaerobic respiration: occurs if oxygen is if oxygen is notnot present present

a. 2 types:a. 2 types:

1. Alcoholic fermentation1. Alcoholic fermentation

2. Lactic acid fermentation2. Lactic acid fermentation

b. Alcoholic fermentationb. Alcoholic fermentation

1. Pyruvic acid is converted 1. Pyruvic acid is converted to carbon dioxide and to carbon dioxide and alcohol alcohol

2. Equation: 2. Equation:

pyruvic acid + NADH pyruvic acid + NADH

alcohol + COalcohol + CO22 + NAD + NAD++

3. Used to make bread 3. Used to make bread (yeast), wine, beer, (yeast), wine, beer, ethanolethanol

c. Lactic acid fermentationc. Lactic acid fermentation

1. Pyruvic acid is converted 1. Pyruvic acid is converted to lactic acid to lactic acid

2. Equation:2. Equation:

pyruvic acid + NADH pyruvic acid + NADH

lactic acid + NADlactic acid + NAD++

3.3. Occurs in animal cellsOccurs in animal cells

- after strenuous exercise, - after strenuous exercise, there is a shortage of there is a shortage of

oxygen going to the oxygen going to the musclesmuscles

- a build-up of lactic acid - a build-up of lactic acid causes muscle fatigue causes muscle fatigue and sorenessand soreness