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8–1 Energy and Life

A.Autotrophs and Heterotrophs

B.Sunlight- main source of energy

C.Chemical Energy and ATP

1.Storing Energy

2.Releasing Energy

D. Using Biochemical Energy

Section 8-1

Section Outline

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Which cell processes require Energy?

•cell division? yes

•Movement of cilia or flagella? yes

•Active transport? yes

•Production of proteins? yes

•Digestion? yes

•Circulation? yes

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Adenine Ribose 3 Phosphate groups

Section 8-1

ATP

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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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oChemical energy and ATP - unstable

- always re-bondsnot used for anything major, anything intracellular

Examples of energy use:active transport

protein synthesis

muscle movement/contractions

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Biochemical Energy

Most cells contain only small amounts of ATP which is enough for a few seconds of activity.

used for small bursts of energy, glucose used for heavy duty movement

1 glucose= 90 times energy of ATP

ATP is NOT good for long term use

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How do cells get the energy stored in ATP?

After ATP is broken down…… energy must be stored immediately(if not it is lost and can never get back once captured the mitochondria holds the energy enzymes from proteins break the bonds between the phosphate groups

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Importance of the ATP cycle….. Cycle:

Remember ENERGY is stored in phosphate bonds.

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Review of ATP1. What does at ATP molecule consist of?

Adenine, ribose and 3 phosphate groups.

2. What do the lines between these parts of the molecule represent?

Chemical bonds.

3. What would be the result if the 3rd phosphate group were removed?

Energy gets released and ADP is created.

4. What is the difference between ADP and ATP?ADP consists of 2 phosphate groups, while ATP consists of 3 phosphate

groups.

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8–2Photosynthesis: An Overview

A. Investigating Photosynthesis

1. Van Helmont’s Experiment

2. Priestley’s Experiment

3. Jan Ingenhousz

B. The Photosynthesis Equation

C.Light and Pigments

Section 8-2

Section Outline

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The Photosynthesis Equation

Carbon dioxide + water (in the presence of sunlight) glucose + oxygen

6 carbon dioxide and 6 water = 1 sugar and 6 oxygen

Turn arrow to show respiration equation

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Photosynthesis: make sugar(monsaccharide) (store in starch, mostly cellulose(polysaccharide) Photosynthesis is divided into two parts or phases….1.Light dependent phase(depends on light)- in thylakoid(needs light, key ingredient is water), oxygen is given off, ATP and NADPH are formed

2.Light independent phase(no need for light, can occur in the dark) known as the CALVIN CYCLE- in stroma(no need for light)

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Light and pigments

chlorophyll is the main pigment used- is the pigment that is energized by sunlight, responsible for making most plants green needed in phase 1. The energy taken signals the enzymes to put between the phosphates and bond them to adenine and ribose.

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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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Light Energy

Chloroplast

CO2 + H2O Sugars + O2

Section 8-2

Photosynthesis: Reactants and Products

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Contributions to Photosynthesis• Jan van Helmont-(1600s) concluded that water is

readily absorbed by plants in large quantities, therefore water must have a critical role in a plant’s life.

• Joseph Priestly-(1770s) plants give off a substance that can keep animals alive and a candle burning.

• Jan Ingenhousz-(1770s) plants do some kind of reaction in the presence of light that allows them to give off oxygen.

• Melvin Calvin-(1940s) traced carbondioxide molecules as they built glucose in the light-independent reaction, now that phase is called the Calvin Cycle.

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Energy carrier – NADP+ (coenzyme- the nonprotein part of an enzyme, helps enyzme)

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NADP NADPH(holds chemical energy)

• From stroma

• Goes thylakoid to get electron and bond to hydrogen ion(comes from splitting water)

• Becomes NADPH

• Goes back to stroma to give energy to Calvin cycle

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Photosynthesis is within a chloroplast!

Photosystems- clusters of pigments and proteins that absorb light energy. This energy will be used to build NADPH and ATP.(in thylakoids)

does photolysis, electrons are energized, (electrons are carried on electron transport train), are bonded to NADP

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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

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Chloroplastsunlight

O2

Sugars

CO2

Light-Dependent Reactions

CalvinCycle

NADPH

ATP

ADP + PNADP+Chloroplast

Section 8-3

Figure 8-7 Photosynthesis: An Overview

H2O

O2

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Purpose of Phases of Photosynthesis

Phase 1- light-dependent

• Photolysis- the splitting of the water molecule in the presence of light

• Store energy- ADP and NADP comes into thylakoid, takes free floating phosphate and hydrogen and forms ATP and and leaves and goes into the stroma.

Phase 2- light-independent

• Creates sugar

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During photosynthesis….

The raw materials are water and carbon dioxide

The end products are sugar and oxygen

The source of energy is sunlight

The source of carbon dioxide is atmosphere

The source of water is roots

What happens to oxygen? It’s is released into the air

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During the light dependent reactions…

What is the energy source? Sunlight

What reactant is necessary? Water

What compounds are produced? Oxygen, ATP and NADPH

Where does the oxygen come from? Water

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During the Calvin cycle….What is the principal reactant? Carbon dioxide

What is the principal product? High-energy sugars

What energy compounds are returned to the light reactions step? ADP and NADP

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Goal of the light dependent reactionsTo use energy to produce ATP and NADPH and release oxygen

What about the water? Gets split into hydrogen and oxygen

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Light dependent reactions-Photosystems I and II

Photosystem I- pigments use energy from light to energize electrons(used in ATP and NADPH)

Photosystem II- energy from light is absorbed by chlorophyll and transferred to electrons, and then these with be transported to photosystem 1 to bond with NADP

Which photosystem occurs first? 2

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Photolysis

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HydrogenIon Movement

Photosystem II

InnerThylakoidSpace

ThylakoidMembrane

Stroma

ATP synthase

Electron Transport Chain Photosystem I

ATP Formation

Chloroplast

Section 8-3

Figure 8-10 Light-Dependent Reactions

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Electron Transport Train

•A series of proteins embedded in the ….. Thylakoid membrane

–Is when electrons are passed among proteins to be received by NADP+ to make NADPH.

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ATP synthase(to make)

helps create ATPs

start with ADP

pushes hydrogen into stroma(no energy required)

while doing this, the protein spins and attracts energy and bonds ADP with a phosphate to hold that energy.

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Factors affecting photosynthesis1.Water

If there is no water, photolysis will not occur, there will be no electrons, transport train shuts down, can’t make NADPH and Calvin cycle shuts down, guard cells also close.

If water decreases, photosynthesis decreases and stops

2.Temperature Most plants can photosynthesize between 0 C- 32 C(32 F- 90 F, there are exceptions)

3.Light intensityAs light increases, photosynthesis increases, but if it continues to go up the plant will

reach its height of photosynthesis and it will stop.

4. Guard Cells-

if guard cells close, photosynthesis stop because CO2 can’t come in and O2 can’t go out

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ChloropIast

CO2 Enters the Cycle

Energy Input

5-CarbonMoleculesRegenerated

Sugars and other compounds

6-Carbon SugarProduced

Section 8-3

Figure 8-11 Calvin Cycle