Cells and Energy

Chapter 4

Mr. Scott

Energy and Life

Energy

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–Without the ability to obtain and use energy, life would cease to exist

Energy and Life

Autotrophs

–Organisms that ______

Plants
–Plants and some other types of organisms are able to use light energy from the sun to produce food

Energy and Life

Heterotrophs

–Organisms that ______

Ex. Animals
–Animals and some other organisms cannot use the sun’s energy directly
Some eat autotrophs
Some eat other animals
Some decompose other organisms

Energy and Life

Chemical energy and ATP

– ______- Adenosine Triphosphate

One of the principle chemical compounds that cells use to ______
Consists of adenine, ribose, and 3 phosphate groups

Energy and Life

–Storing Energy

ADP
–Adenosine diphosphate
–Two phosphates instead of three phosphates
–Adding a ______to ADP produces ATP
ADP  ATP

Energy and Life

–Releasing Energy

The characteristics of ATP make it exceptionally useful as the ______
ATP  ADP

Energy and Life

Uses Biochemical Energy

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Sodium-potassium pump
–Pumps sodium out of and potassium into the cell

–Cellular movement

–Organelle functioning

Organelle ______within the cell

–Storage

ATP is not good at storing energy
______is better than ATP for long term storage
90 times more energy

Photosynthesis

Investigating Photosynthesis

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Plants use the sunlight to convert water and carbon dioxide into carbohydrates and oxygen

Photosynthesis

–Van Helmont’s Experiment

Where does the mass of a tree come from?
The mass comes from the water
–Soils mass was nearly unchanged
–Water was the only thing added
–Other things were not taken into consideration by Van Helmont

Photosynthesis

–Priestly’s Experiment

Lit candle in a jar experiment

–Flame gradually went out
Something in the air allowed the candle to burn
What was this substance?

Photosynthesis

–Priestly – Part 2

He placed a mint leaf in one jar and the candle in another

Mint plant allowed the flame to last much longer

Mint plant produced something that the candle flame required

What was this substance?

Photosynthesis

–Jan Ingenhousz Experiment

Lit candle in a jar with mint plant and no light

–Flame did not last as long as with mint plant in light

–What does this demonstrate?

Light is necessary for plants to produce oxygen!

Photosynthesis

Photosynthesis uses the ______to convert ______into ______

Photosynthesis

Photosynthesis Equation

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–Carbon Dioxide + Water (with light)  Sugars + Oxygen

Photosynthesis

Light and Pigment

–The equation tells you what is needed, BUT not what happens

–Photosynthesis requires light and a substance called ______

Found in chloroplasts

Makes plants look green

Photosynthesis

–Sun’s energy travels to Earth as light

______are molecules that absorb light

Chlorophyll is the main pigment in plants

–Why are plants green?

–Plants absorb all of the light spectrum except for green

–The ______that is absorbed is converted to ______in the electrons of the chlorophyll

Photosynthesis

Two different types of chlorophyll

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–

Not all plants are green…How?

–Some plants contain red or orange (carotene) that make them different colors

The Reactions of Photosynthesis

Inside a Chloroplast

–The organelle where photosynthesis takes place

–Saclike photosynthetic membranes

–Stacks of thylakoids

–Clusters of pigment and protein that absorb light energy

–Area outside of the thylakoid in the chloroplast

The Reactions of Photosynthesis

Electron Carriers

–

Transports the electrons between photosystems

–Transport high-energy electrons to other molecules

Electrons ______from sunlight

These electrons exist inside the chlorophyll

Something has to be done with these electrons

The Reactions of Photosynthesis

–NADP+

Chloroplasts trap energy from the sun

Two electrons and a hydrogen molecule make NADPH

NADPH can move to other parts of the cell and make things like glucose

The Reactions of Photosynthesis

Light-Dependent Reactions

–Produce ______and convert ADP and NADP+into the energy carriers ATP and NADPH

The Reactions of Photosynthesis

–Photosystem II pigments absorbs light

Light absorbance ______to a higher energy level

High-energy electrons move to the electron transport chain

Thylakoid replaces lost electrons from stored ______

– Two hydrogen molecules (New Electrons)

– One oxygen (Waste)

The Reactions of Photosynthesis

–High-energy electrons move from photosystem II to photosystem I

Energy from the electrons is used to move ______from the stroma to the inner thylakoid space

The Reactions of Photosynthesis

–Photosystem I uses light to reenergize the electrons

 NADP+ picks up the high-energy electrons and hydrogen ions to make NADPH

The Reactions of Photosynthesis

–______are pumped across the thylakoid membrane

This happens until the inside of the thylakoid is positive and the outside is ______

This results in energy that can be used to make ATP –the useable form of energy for the plant cell!

The Reactions of Photosynthesis

–Hydrogen ions cannot pass through the thylakoid membrane directly

–______– membrane protein

–Allows hydrogen to pass through

–ATP synthase will bind ADP and phosphate  ATP

The Reactions of Photosynthesis

Summary of light reactions:

–Water breaks down - hydrogen ions and oxygen

–NADP+ becomes NADPH – electrons and hydrogen ions to photosystem I

–ADP to ATP via ATP synthase

–YEAH!!! We have ATP, now what?

The Reactions of Photosynthesis

Calvin Cycle

–Uses ______from the light dependent reactions to produce high-energy sugars

–Does NOT require ______to proceed – it uses the energy captured from the light reactions.

–This is where carbon dioxide (CO2) is used.

The Reactions of Photosynthesis

Factors affecting photosynthesis

–H2O

Plants require water for photosynthesis to occur

 Dry conditions -

–Temperature

______require temperature range of 0o – 35o C

–Light Intensity

The more ______the more photosynthesis to a point

Cellular Respiration

Chemical Energy and Food

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The amount of energy needed to raise the temperature of 1 gram of water 1 oC

______is equal to ______

–This is the one on food labels

Cellular Respiration

Cellular Respiration

–Process that releases energy by breaking down glucose and other food molecules in the presence of oxygen.

Cellular respiration - If oxygen is present for glycolysis then Krebs cycle and the electron transport chain come after

–

Cellular Respiration

Glycolysis

–The process in which one molecule of ______is broken in half, producing two molecules of pyruvic acid, a 3-carbon compound

Cellular Respiration

– ATP Production

2 ATP molecules are used in the production

 4 ATP molecules are produced

 2 ATP molecules are gained or there is a 2 net gain

Cellular Respiration

–NADH Production

______4 high-energy electrons and passes them to NAD+

NADH is made and will hold the electrons to be transferred to other molecules

Glycolysis cannot continue this process forever without oxygen

Cellular Respiration

Fermentation

–Process that releases energy from food molecules by making ATP without oxygen.

–Process that does ______

Cellular Respiration

–Alcoholic Fermentation

pyruvic acid + NADH ______+ CO2 + NAD+

–Yeast in the bread dough causes this process to make bread rise

Cellular Respiration

–Lactic Acid Fermentation

pyruvic acid + NADH ______+ NAD+

–This is why your muscles burn

–This process is used to make cheese, yogurt, buttermilk, and sour cream

Krebs and Electron Support

Krebs and electron transport

After glycolysis

–______of total energy is still unused

Aerobic

– Require oxygen

Krebs and Electron Support

Krebs Cycle

–Also called the ______

–______is broken down into carbon dioxide in a series of energy-extracting reactions

Krebs and Electron Support

– Citric acid production

Pyruvic acid comes into the mitochondrion

One carbon breaks off

The other two carbons combine with coenzyme A forming Acetyl-CoA

Acetyl-CoA combines with a 4-carbon molecule to make citric acid

Krebs and Electron Support

–Energy extraction

Citric acid is broken down and electrons are transferred to electron carriers

–One carbon is removed, then another carbon

Making CO2

This is why you exhale CO2

–ATP is produced

It is used for cell activities

–NAD+ and FAD

Convert to NADH and FADH2

Can produce ______

Krebs and Electron Support

Electron Transport

–The electron transport chain uses ______from the Krebs cycle to convert ADP into ATP

Krebs and Electron Support

–Electron transport

High-energy electrons are transferred from NADH and FADH2 to the electron transport chain

These electrons connect to ______to make water

Krebs and Electron Support

–Hydrogen ion movement

Two high-energy electrons cause a H+ to move across the cell membrane

This makes the inside of the mitochondria positively charged

–ATP production

H+ ions leave the mitochondria causing the ATP synthase to spin making one ATP from one ADP for each rotation

Krebs and Electron Support

The Totals

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2 ATP/Glucose molecule

–

34 ATP/Glucose molecule

–Total

______ATP/Glucose

38% of total energy of glucose

Krebs and Electron Support

Energy and Exercise

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Use of stored ATP

Lasts for up to 90 seconds

Lactic acid is produced

Krebs and Electron Support

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Energy is produced for a longer period of time

–Glycogen

–Lasts for 15 to 20 minutes