UNIT 5: PHOTOSYNTHESIS& CELLULAR RESPIRATION

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ENERGY AND LIFE Living things depend on energy

Sun is source of most energy

2 types of organisms, – AUTOTROPHS make their own food (Ex: plants,

bacteria*, protists*)– HETEROTROPHS get energy from the foods they

consume (animals, fungi)

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KEY CONCEPT: PHOTOSYNTHESISThe overall process of photosynthesis produces sugars that store chemical energy.

Photosynthetic organisms are producers.

Plants use photosynthesis and are producers/(autotrophs.)

Photosynthesis captures energy from sunlight to make sugars.

Research On Photosynthesis

– VAN HELMONT- determined in the 1600’s that plants grew because of water.

– PRIESTLEY- found that plants release oxygen.

– JAN INGENHOUSZ- found aquatic plants produce oxygen bubbles in the light, therefore plants need sunlight to produce oxygen

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AN OVERVIEW OF PHOTOSYNTHESIS

Plants use the energy of sunlight to

– convert water & carbon dioxide into high energy carbohydrates (sugar)

– oxygen is a waste product.

light

6H2O + 6CO2 → C6H12O6 + 6O2

Reactants Products

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What Else Does The Photosynthesizer Need?

Chlorophyll- a chemical pigment that traps the energy of the sun and converts it to chemical energy

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Capturing Light Energy

White light= ROY G BIV Chlorophyll captures (absorbs) energy at the

ends of the spectrum (red/orange & blue/violet) What you see is the wavelengths that are

reflected. (green)

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Where Photosynthesis Occurs

In the chloroplast

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Chlorophyll is a molecule that absorbs light energy.

chloroplast

leaf cell

leaf

• In plants, chlorophyll is found in organelles called chloroplasts.

Where Photosynthesis Occurs

Photosynthesis is Many ReactionsThe equation for the overall process is:

6CO2 + 6H2O C6H12O6 + 6O2

C6H12O6

granum (stack of thylakoids)

thylakoid

sunlight

1 six-carbon sugar

6H2O

6CO2

6O2

chloroplastchloroplast1

2

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energy

stroma (fluid outside the thylakoids)

FACTORS THAT AFFECT PHOTOSYNTHESIS

Amount of Water

Amount of CO2

Temperature

Intensity of Light

Wavelength of light

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KEY CONCEPT The overall process of cellular respiration converts sugar into ATP (energy) using oxygen.

Cellular Respiration

CHEMICAL ENERGY AND ATP

All living things use chemical energy A chemical compound that cells use to store and

release energy is ATP (ADENOSINE TRIPHOSPHATE).

ATP is like a fully charged battery ready to power the machinery of a cell.

ATP powers many cellular activities Ex: – active transport across cell membranes, – protein synthesis – muscle contraction.

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Cellular respiration makes ATP (energy) by breaking down sugars.

Cellular respiration is aerobic, or “requires oxygen.”

Cell respiration takes place in mitochondria.

mitochondrion

animal cell

Cellular Respiration

6H O2

6CO 2

6O 2

mitochondrionmitochondrion

matrix (area enclosedby inner membrane)

inner membrane

ATP

ATP

energy

energy from glycolysis

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2

4

3

and

and

and

• The electron transport chain produces a large amount of ATP (energy.)

– oxygen enters process

– PRODUCT

– ATP

– WASTE PRODUCTS:

– Water

– Carbon dioxide

Electron Transport

Cellular Respiration

The equation for the overall process is:

C6H12O6 + 6O2 6CO2 + 6H2O

• The reactants in photosynthesis are the same as the products of cellular respiration.

Cellular Respiration

ATP synthase (don’t copy)

Is an enzyme (“-ase” ending is a hint)

Is a membrane protein.

It is a protein pump that allows H+ ions to pass thru the cell membrane

This is necessary for the formation of ATP

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Quick Review of Organic Molecules in Living Things

Carbohydrates (sugars, starches, etc.) Proteins Lipids (mainly fats) Nucleic acids (ATP, NADP, RNA, DNA)

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Cellular Respiration

• Cells do not “burn” glucose, instead they slowly release energy from glucose

• They do this in many small steps-

• WHY?

If all the energy was released once, it would be too much for the cell

and it would be destroyed!20

When O2 is not present, a process called FERMENTATION takes place.

FERMENTATION releases a small amount of ATP (energy) from sugar.

ANAEROBIC RESPIRATION

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1. ALCOHOLIC FERMENTATION produces carbon dioxide and alcohol.

This type of fermentation causes bread dough to rise.

.

2 Types of Fermentation

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2 Types of Fermentation, cont.

2. LACTIC ACID FERMENTATION is produced in your muscles during rapid

exercise when the body can’t get enough oxygen to the tissues.

With rapid exercise your muscles run out of oxygen. Your muscle cells rapidly begin to produce ATP by LACTIC ACID FERMENTATION

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Fermentation

Also occurs in the CYTOPLASM

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