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Photosynthesis (Chapter 8)With light To make

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The purpose of photosynthesis is to produce food & oxygen

ATP

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I. Energy & LifeA. Overview

1. The cell process identified with energy production is photosynthesis.

2. Plants use solar energy to convert water & carbon dioxide into high energy sugars (food) & oxygen.

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I. Energy & Life3. Organisms that can make their own

food from the sun are called autotrophs

What does autotroph mean? Auto = self, troph = nutrition

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I. Energy & Life4. Organisms that can not use the sun’s

energy to make food are called heterotrophs. They obtain energy from food they eat.

Herbivore - ImpalasCarniovore - Leopard

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1. Cells use adenosine triphosphate, abbreviated ATP to store & release energy.

2. ATP is used by all types of cells as their basic energy source.

B. Chemical Energy & ATP

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3. ATP consists of:• adenine• ribose (a 5-carbon sugar)• 3 phosphate groups

Adenine

ATP

Ribose 3 Phosphate groups

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4. Storing Energya. ADP has two phosphate groups

instead of three.b. A cell can store small amounts of

energy by adding a phosphate group to ADP.

ADP ATP

Energy

Energy

Partiallycharged battery

Fullycharged battery

+

Adenosine Diphosphate (ADP) + Phosphate

Adenosine Triphosphate (ATP)

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5. Releasing Energya. Energy stored in ATP is released by

breaking the chemical bond between the second and third phosphates.

P

ADP

2 Phosphate groups

BLAMO!!

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6. ATP energy is used for Lots of stuff like:

a. active transport across cell membranes.

b. protein synthesis.c. muscle contraction.d. ATP is the basic energy source

of ALL cells!

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ATP Movie

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Organisms that make their own food are calleda.autotrophs.b.heterotrophs.c.decomposers.d.consumers.

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Most autotrophs obtain their energy froma.chemicals in the

environment.b.sunlight.c.carbon dioxide in the air.d.other producers.

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How is energy released from ATP?a.A phosphate is added.b.An adenine is added.c.A phosphate is removed.d.A ribose is removed.

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How is it possible for most cells to function with only a small amount of ATP?a. Cells do not require ATP for

energy.b. ATP can be quickly regenerated

from ADP and P.c. Cells use very small amounts of

energy.d. ATP stores large amounts of

energy.

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Compared to the energy stored in a molecule of glucose, ATP storesa. much more energy.b. much less energy.c. about the same amount of

energy.d. more energy sometimes and less

at others.

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II. PhotosynthesisA.The Photosynthetic Equation:

6CO2 + 6H2O C6H12O6 + 6O2

CarbonDioxide

Water Sugars OxygenLight

Light

B. Photosynthesis uses sunlight to convert water & carbon dioxide into high energy sugars (carbohydrates) & oxygen.

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C. Light & Pigments1. Plants gather the sun's energy

with light-absorbing molecules called pigments.

2. The main pigment in plants is chlorophyll.

3. There are two main types of chlorophyll:

a.chlorophyll a b.chlorophyll b

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Plant leaves are green (usually) because they contain the pigment chlorophyll inspecial cell organelles called chloroplasts.

Spirogyra sp., a filamentous green alga

chloroplasts

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Sunlight contains different wavelengthsof light. Different wavelengthshave different colors & amount of energy.

What causes a rainbow??

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C. Light and Pigments (cont.)4. Chlorophyll absorbs light in the blue-

violet and red regions of the visible spectrum.

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5. Chlorophyll reflects light in the green region of the spectrum, which is why plants look green.

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6. Chlorophyll absorbs light energy & the energy is transferred to electrons in the chlorophyll molecule. Raising the electrons energy.

7. These high-energy electrons are what make photosynthesis work.

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Plants use the sugars produced in photosynthesis to makea.oxygen.b.Sugars (starches,

carbohydrates).c.carbon dioxide.d.protein.

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The raw materials required for plants to carry out photosynthesis area. carbon dioxide and oxygen.b. oxygen and sugars.c. carbon dioxide and water.d. oxygen and water.

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The principal pigment in plants isa.chloroplast.b.chlorophyll.c. carotene.d.carbohydrate.

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The colors of light that are absorbed by chlorophylls area. green and yellow.b. green, blue, and violet.c. blue, violet, and red.d. red and yellow.

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III. Photosynthesis ReactionsA. The chloroplast

1. Photosynthesis takes place inside the chloroplasts of plants & algae.

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Chloroplasts of plants & algae.

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2. Chloroplasts contain thylakoids—saclike photosynthetic membranes.

Chloroplast

Singlethylakoid

Stroma

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3. Thylakoid membrane organize chlorophyll into clusters called photosystems, which collect light.

Chloroplast

Photosystems

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B. Photosynthetic reactions1. There are two types of

photosynthesis reactions:a. Light-dependent reactions take

place in the thylakoid membranes.b. Calvin cycle (Light-independent)

reactions takes place in the stroma (outside the thylakoid membranes).

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Light-Dependent Reactions

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Chloroplast

LightH2O

O2

CO2

Sugars

NADP+

ADP + P

Calvin Cycle

Light- dependent reactions

Calvin cycle

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Light-Dependent Reactions (fig 8-10)

2H2O

Produce: Oxygen, ATP, & NADPH (electron carrier).

+ O2

ATP synthase

ADP2 NADP+

2 NADPH2

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2. Light-dependent stepsa. Reactions occur in the thylakoid

membranes of chloroplastsb. Light is absorbed by chlorophyll

molecules in the thylakoid membrane.

Thylakoidmembrane

Chloroplast

Stroma

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2. Light-dependent Steps (Fig 8-10)c. Water is broken down into

hydrogen ions oxygen atoms – we breath energized electrons

2H2O+ O2

InnerThylakoidspace

ThylakoidMemebrane

Stroma Chlorophyll

e- carriers

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2. Light-dependent Stepsd. Electrons move through the electron

transport chain & carry H+ ions from the stroma into the inner thylakoid space.

ADP

Stroma

InnerThylakoidspace

ThylakoidMemebrane

e- carriers

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2H2O

+ O2

2 NADP+

2 NADPH2

2. Light-dependent Stepse. NADP+ then picks up these high-energy

electrons, along with H+ ions, and becomes NADPH.

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2. Light-dependent Stepsf. Hydrogen ions pass through ATP

synthase & convert ADP into ATP.

ADPStroma

ThylakoidMemebrane

InnerThylakoidspace

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3. Light-Dependent Productsa. The light-dependent reactions use

sunlight, H2O, & CO2 to produce:i. Oxygenii. Change ADP into ATPiii.Change NADP+ into high-energy

electron carrier NADPH.

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4. Calvin Cycle (light-independent reaction)

a. The Calvin cycle takes place in the stroma of chloroplasts & does not require light.

b. The Calvin cycle uses CO2 + ATP & NADPH (created in light-dependant reactions) to produce sugars.

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Inside a Chloroplast

Chloroplast

LightH2O

O2

CO2

Sugars

NADP+

ADP + P

Calvin Cycle

Light- dependent reactions

Calvin cycle

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4. Calvin Cycle (light-independent reaction)

c. Key Steps:i. 6 CO2 molecules from atmosphere

combine with 6 -5 carbon molecules know as RuBP. Product splits into 2 -3carbon molecules.

ii. Energy from ATP & NADPH convert three carbon molecules into higher energy forms known as G3P.

iii. Every 6 cycles produces 2 three carbon molecules which are used to create sugars, lipids, other compounds.

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12 NADPH

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12 ADP

12 NADP+

5-Carbon MoleculesRegenerated

Sugars and other compounds

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6 ADP

Calvin Cycle fig. 8-11

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Photosynthesis

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Photosynthesis

includes

of

take place intakes place in uses

to produce to produce

use

Section 8-3 Photosynthesis Concept Map

Light-dependentreactions

Calvin cycle

Energy fromsunlight

Thylakoidmembranes Stroma ATPNADPH

ATP NADPH O2 ChloroplastsHigh-energysugars

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What are the products of photosynthesis?

ATP

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What are the raw materials of photosynthesis?

ATP

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What is the energy source of photosynthesis?

ATP

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In plants, photosynthesis takes place inside thea.thylakoids.b.chloroplasts.c.photosystems.d.chlorophyll.

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Energy to make ATP in the chloroplast comes most directly froma. hydrogen ions flowing through an

enzyme in the thylakoid membrane.

b. transfer of a phosphate from ADP.

c. electrons moving through the electron transport chain.

d. electrons transferred directly from NADPH.

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NADPH is produced in light-dependent reactions and carries energy in the form ofa.ATP.b.high-energy electrons.c. low-energy electrons.d.ADP.

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What is another name for the Calvin cycle?a.light-dependent reactionsb.light-independent reactions

c.electron transport chaind.photosynthesis