Ms. Nguyen

Biology

Chapter 8: The Process of

Photosynthesis

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Chapter 8 Big Idea: Cellular Basis of Life

Essential Question: How do plants and other

organisms capture energy from the sun?

8.1 Main Question: How do Organisms story

energy?

8.2 Main Question: What Cellular structures

and molecules are involved in photosynthesis?

8.3 Main Question: How do photosynthetic

organisms convert the sun’s energy into chemical

energy?

Bell Ringer

Chapter 7: Flashback

1) Diffusion

2) Facilitated Diffusion

3) Osmosis (water)

1) Endocytosis

2) Exocytosis

A. Passive Transport

B. Active Transport

Lesson Overview

8.1 Energy and Life

Bell Ringer Homeostasis is hard work. Organisms and the

cells within them have to grow and develop, move

materials around, build new molecules, and

respond to environmental changes.

1) What powers so much activity, and where does

that power come from?

I. Chemical Energy and ATP

A. What is ATP?

1. ATP = release and store energy by

breaking and re-forming the bonds

between its phosphate groups.

2. ATP = basic energy source for all

cells.

B. Why is ATP useful to cells

1. Energy = ability to do work

2. Energy = build new molecules,

contract muscles, and carry out active

transport.

3. No energy = no life

C. How is ATP

formed? 1. Adenosine triphosphate (ATP)

2. ATP = Adenine, ribose, and three

phosphate groups

3. Adenine and Ribose = a 5-carbon sugar

II. ADP versus ATP

A. Adenosine

diphosphate (ADP) 1. ADP = two phosphate groups > not

as much as ATP.

2. When a cell has energy available, it

can store small amounts of it by

adding phosphate groups to ADP,

producing ATP.

ADP is like a rechargeable battery

that powers the machinery of the

cell.

III. Releasing Energy

A. Purpose of

ATP and ADP 1. Cells can release the energy stored

in ATP by breaking the bonds between

the second and third phosphate

groups.

2. Because a cell can add or subtract

these phosphate groups, it has an

efficient way of storing and releasing

energy as needed

3. ATP > carry out active transport

IV. Using Biochemical Energy

A. ATP = energy

for movement 1. ATP = powers movement > energy

for motor proteins that contract

muscle and power the movement of cilia and flagella

B. ATP = protein

synthesis 1. ATP = powers the synthesis of

proteins and responses to chemical

signals at the cell surface.

C. ATP does not

store large amounts

of energy

1. Cells can regenerate ATP from ADP

as needed by using the energy in

foods like glucose.

V. Heterotrophs and Autotrophs

A. Heterotrophs

1. Organisms that obtain food by

consuming other living things

2. Some eat plants.

3. Some indirectly eat plants by

feeding on plant-eating animals.

4. Some (mushrooms) decompose

other organisms.

B. Autotrophs

1. Organisms that make their own

food

2. Example: Plants, algae, and some

bacteria.

3. Photosynthesis- use the energy of

sunlight to produce high-energy

carbohydrates that can be used for

food.

Lesson Overview

8.2 Photosynthesis:

An Overview

Bell Ringer .

1) Compare and contrast heterotrophs

and autotrophs.

VI. Chlorophyll and

Chloroplasts

A. What role do

pigments play in

the process of

photosynthesis?

B. Light

.

1. Photosynthetic organisms capture

energy from sunlight with

pigments

1. Energy from the sun travels to

Earth in the form of light.

2. Sunlight = mixture of different

wavelengths, many of which are

visible to our eyes and make up the

visible spectrum.

C. Pigments 1. Plants gather the sun’s energy with

light-absorbing molecules

2. The plants’ principal pigment is

chlorophyll

-chlorophyll a and chlorophyll b

>blue-violet and red regions

- Carotene > red and orange

D. Chloroplasts 1. Photosynthesis takes place inside

organelles called chloroplasts.

2. Chloroplasts = saclike

photosynthetic membranes called

thylakoids, which are interconnected

and arranged in stacks known as

grana.

VII. Energy Collection

A. Light into Energy 1. Light = energy

2. Chlorophyll absorbs visible light

Chlorophyll = light electron =

photosynthesis = energy

VIII. An Overview of Photosynthesis

A. What are the

reactants and

products of

photosynthesis?

1.Photosynthesis uses the energy of

sunlight to convert water and carbon

dioxide (reactants) into high-energy

sugars and oxygen (products).

B. Sugar

becomes… Plants use the sugars generated by

photosynthesis to produce complex

carbohydrates such as starches, and

to provide energy for the synthesis of

other compounds, including proteins

and lipids.

IX. Light versus Light Independent

A. Photosynthesis

involves two sets

of reactions.

1. Light-dependent reactions because

they require the direct involvement of

light and light-absorbing pigments.

2. Light-independent reactions, ATP

and NADPH molecules produced in the

light-dependent reactions are used to produce high-energy sugars from carbon

1 Light-dependent: use energy from

sunlight to produce ATP and NADPH. 2.These reactions

take place inside the thylakoid

membranes of the chloroplast. 3.Water

is required as a source of electrons and hydrogen ions. Oxygen is released

as a byproduct

1. Light independent: No light is required to power the light-

independent reactions. 2.

Reactions take place outside the thylakoids, in the

stroma.

Lesson Overview

8.3 The Process of

Photosynthesis

Bell Ringer What happens during the light-dependent reactions

compared to light-independent reactions?

X. Summary of the Calvin Cycle

A. The Calvin cycle uses

6 molecules of carbon

dioxide to produce a

single 6-carbon sugar

molecule.

Summary of the Calvin Cycle

B. The energy for the

reactions is supplied by

compounds produced in

the light-dependent

reactions.

Summary of the Calvin Cycle

C. The plant uses the

sugars produced by the

Calvin cycle to meet its

energy needs and to

build macromolecules

needed for growth and

development.

D. When other organisms

eat plants, they can use

the energy and raw

materials stored in these

compounds.

The End Results E. The two sets of photosynthetic reactions work

together—the light-dependent reactions trap the

energy of sunlight in chemical form, and the light-

independent reactions use that chemical energy to

produce stable, high-energy sugars from carbon

dioxide and water.

In the process, animals, including humans, get

food and an atmosphere filled with oxygen.

XI. Temperature, Light, and

Water A. The reactions of

photosynthesis are made

possible by enzymes that

function best between 0°C

and 35°C.

B. Temperatures above or

below this range may

affect those enzymes,

slowing down the rate of

photosynthesis or

stopping it entirely.

Temperature, Light, and Water C. High light intensity increases the rate of

photosynthesis.

D. After the light intensity reaches a certain level,

however, the plant reaches its maximum rate of

photosynthesis, as is seen in the graph.

Temperature, Light, and Water E. Because water is one of the raw materials in

photosynthesis, a shortage of water can slow or

even stop photosynthesis.

F. Water loss can also damage plant tissues.

G. Plants that live in dry conditions often have waxy

coatings on their leaves to reduce water loss. They

may also have biochemical adaptations that make

photosynthesis more efficient under dry conditions.

XII. CAM Plants

A. Members of the Crassulacae family, such as cacti

and succulents, incorporate carbon dioxide into

organic acids during photosynthesis in a process

called Crassulacean Acid Metabolism (CAM).

CAM Plants

B. CAM plants admit air into their leaves only

at night, where carbon dioxide is combined

with existing molecules to produce organic

acids, “trapping” the carbon within the

leaves.

C. During the daytime, when leaves are

tightly sealed to prevent water loss, these

compounds release carbon dioxide,

enabling carbohydrate production.

D. CAM plants include pineapple trees,

many desert cacti, and “ice plants”.