Objective

Students will be able to verbally list the reactants and products of Photosynthesis by the end of the period.

PhotosynthesisChapter 8

Ag Biology

Ms. Prescott

8-1 Energy and Life

8-2 Photosynthesis

8-3 Light-Dependent Reactions & Calvin Cycle

8-1Energy and Life

Saving for a Rainy Day

Suppose you earned extra money by having a part-time job. At first, you might be tempted to spend all of the money, but then you decide to open a bank account.

1. What are the benefits of having a bank account?

2. What do you have to do if you need some of this money?

3. What might your body do when it has more energy than it needs to carry out its activities?

4. What does your body do when it needs energy?

8-1 Vocabulary

Autotroph- organism that can capture energy from sunlight or chemicals and use it to produce its own food from inorganic compounds; also called a producer

Heterotroph- organism that obtains energy from the foods it consumes; also called a consumer

Adenosine triphosphate (ATP) – one of the principal chemical compounds that living things use to store energy.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

8-1 Energy and Life

1. Autotrophs and Heterotrophs

a. Autotrophs: organisms, like plants, that use light energy from the sun to produce their own food Because plants can “manufacture” their own energy directly, they are self-sufficient.

b. Heterotrophs: organisms that obtain energy from foods they consume

All other forms of life, such as humans, animals, insects and even bacteria, depend on other living things for sustenance.

8-1 Energy and Life2. Chemical Energy and ATP

a. The cell’s activities are powered by chemical fuels

i. ATP is a compound that living things use to store energy

ii. ADP is the compound used to store energy in cells

i. It can hold one more phosphate when energy is needed

ii. Energy is released when ATP converts to ADP

Adenine Ribose 3 Phosphate groups

ADP ATP

Energy

EnergyAdenosine diphosphate (ADP) + Phosphate Adenosine triphosphate (ATP)

Partiallychargedbattery

Fullychargedbattery

Section 8-1

Figure 8-3 Comparison of ADP and ATP to a Battery

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ADP ATP

Energy

EnergyAdenosine diphosphate (ADP) + Phosphate Adenosine triphosphate (ATP)

Partiallychargedbattery

Fullychargedbattery

Section 8-1

Figure 8-3 Comparison of ADP and ATP to a Battery

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8-1 Energy and Life

b. ATP and Glucosea. Most cells only have a small amount of ATP,

enough to last for only a few seconds of activity because it is not good for storing large amounts of energy for long periods of time

a. Glucose stores more than 90 times the energy of a molecule of ATP

b. Cells can regenerate ATP from ADP as needed by using the energy in carbohydrates, like glucose

8-2 / 8-3Photosynthesis:

An Overview

8-2 Interest Grabber Trapping EnergyHave you ever used a solar-powered calculator? No

matter where you go, as long as you have a light source, the calculator works. You never have to put batteries in it.

1. A solar-powered calculator uses solar cells that are found in rows along the top of the calculator. Into what kind of energy is the light energy converted so that the calculator works?

2. Recall that plants use light energy from the sun to make food. Into what kind of energy is the light energy converted by plants?

3. Most plants, no matter what size or shape they are, have some parts that are green. Which parts of a plant are usually green?

4. What does the green color have to do with the plant’s ability to convert light energy into the energy found in the food it makes?

8-2/8-3 VocabularyPhotosynthesis-

process by which plants and some other organisms use light energy to power chemical reactions that convert water and carbon dioxide into oxygen and high-energy carbohydrates such as sugar and starches.

Pigment- light-absorbing colored molecule

Chlorophyll- principal pigment of plants and other photosynthetic organisms; capture light energy

Thylakoid-Saclike body in chloroplasts made of photosynthetic membranes that contain photosystems.

8-2/8-3 Photosynthesis Notes1. The Photosynthesis Equation

a. Photosynthesis uses the energy of sunlight to convert carbon dioxide and water into high-energy sugar and oxygeni. 6C02 + 6H2O C6H12O6 +602

Chemically:

6C02 + 6H2O C6H12O6 +602

Green Plant

Light Energy

( Carbon dioxide + Water Sugar + Oxygen)

Written:“Six molecules of carbon dioxide plus six molecules of water combine in the presence of a green plant and light energy to form one molecule of sugar and six molecules of oxygen.”

8-2/8-3 Photosynthesis2. Light and Pigments

a. In addition to water and carbon dioxide, photosynthesis requires light and chlorophyll, a molecule in chloroplasts

b. Plants gather the sun’s energy with light-absorbing molecules called pigments

a. The principal pigment is chlorophyll

b. Energy molecules released from the reaction are ATP & NADPH

Light Energy

Chloroplast

CO2 + H2O Sugars + O2

Section 8-2

Photosynthesis: Reactants and Products

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Absorption of Light byChlorophyll a and Chlorophyll b

V B G YO R

Chlorophyll b

Chlorophyll a

Section 8-2

Figure 8-5 Chlorophyll Light Absorption

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8-2/8-3 Photosynthesis3. Inside a Chloroplast

a. Chloroplasts contain saclike photosynthetic membranes call thylakoids arranged in stacks

b. The thylakoids contain clusters of chlorophyll and other pigments and protein known as photosystems

c. There are two stages to photosynthesis used to make glucose

i. Light-dependent reactions: take place in the thylakoid

ii. Light-independent reactions (Calvin Cycle): takes place in the stroma, outside the thylakoid

8-3Light-Dependent Reactions

& Calvin Cycle

8-3 VocabularyThylakoid-

saclike body in chloroplasts made of photosynthetic membranes that contain photosystems

Stroma- region outside the thylakoid membranes in chloroplasts

NADP+ (Nicotinamide adenine dinucleotide) –

one of the carrier molecules that transfer high-energy electrons from chlorophyll to other molecules.

8-3 Vocabulary

Light-dependent reaction- reactions of photosynthesis that use energy from light to produce ATP and NADPH

ATP synthase- large protein that uses energy from H+ ions to bind ADP and a phosphate group together to produce ATP

Calvin Cycle- reactions of photosynthesis in which energy from ATP and NADPH is used to build high-energy compounds such as sugars.

8-3 Light-dependent Reactions1. Light-Dependent Reactions

a. Light dependent reactions produce oxygen gas and convert ADP into energy carrier ATP

a. Water is split to produce H+ and O2 (oxygen)

b. Light energy is converted into chemical bond energy (ATP and NADPH)

8-3 Calvin Cycle2. The Calvin Cycle

a.The Calvin Cycle uses energy from the light-dependent reactions to make sugars

b.As photosynthesis continues, the Calvin Cycle runs, producing sugars while removing carbon dioxide from the atmosphere

ChloropIast

CO2 Enters the Cycle

Energy Input

5-CarbonMoleculesRegenerated

Sugars and other compounds

6-Carbon SugarProduced

Chloroplast

Light

O2

Sugars

CO2

Light-Dependent Reactions

CalvinCycle

NADPH

ATP

ADP + PNADP+Chloroplast

Section 8-3

Figure 8-7 Photosynthesis: An Overview

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Photosynthesis

includes

of

take place intakes place in uses

to produce to produce

use

Light-dependentreactions

Calvin cycle

Thylakoidmembranes Stroma NADPHATPEnergy from

sunlight

ATP NADPH O2 Chloroplasts High-energysugars

Section 8-3

Concept Map