Cellular Energy

Chemical Energy and ATP

Most cell processes use ATP for energy Do you get energy from eating sugar?

Yes? No?

All cells use ATP

ATP is a molecule that transfers energy How is ATP like money in your wallet?

ATP is used to: Build molecules Move materials

Structure of ATP

Energy is released when a phosphate group is removed from the molecule

ATP = Adenosine TRI-phosphate

ATP

When the third P is removed, energy is released

Unstable and easily removed for energy

ATP = ADP + P ADP = Adenosine DI-

phosphate

ATP and ADP

Questions

Where are molecules from food involved in the cycle of ADP to ATP?

Describe the relationship between energy stored in food and ATP.

How many ATP?

Carbohydrates offer easy ATP Carbs are not stored in the body

One glucose = 36 ATP molecules!

Proteins about the same as Carbs Not typically used for energy but to build

more proteins

Fats (lipids) offer the most ATP One triglyceride = 146 ATP molecules

How do plants eat?

They make their own food

Plants absorb energy from the sun and make sugars to break down for ATP

Chemosynthesis

Some species of bacteria use chemicals to make food

They break the food down for ATP

Solar Energy?

Calculators, homes and cars use energy from sunlight

Energy for people comes from ATP ATP comes from the breakdown of

sugars How are sugars made?

Photosynthetic organisms

Producers – organisms that produce the source of chemical energy for themselves and for other organisms Plants Bacteria Protists

Basic Food Chains

Animals eat plants = consumers Animals that eat other animals, bacteria

and fungi that decompose organisms Wolf eats rabbit, rabbits tissues supply

energy to wolf, tissues were built from plants, which made the sugars and other carbon-based molecules

Photosynthesis

Plant cells use sunlight energy to make organic compounds

Directly or indirectly, the energy for almost all organisms begins as sunlight

Sunlight and Radiant Energy

Ultraviolet Microwaves Visible light or Radio waves?

Plants absorb visible light

Where does it occur?

In the leaves!

Photosynthesis occurs in the chloroplast.

Anatomy of a chloroplast

chloroplast

stroma

grana (thylakoids)

Chloroplasts

Contain Thylakoids (flattened sacs) Have pigments in their membranes

Grana - Stacks of thylakoids Stroma - Fluid inside

chloroplast

chloroplast

stroma

grana (thylakoids)

Pigments

Chlorophyll Green pigment

Two forms - a and b Absorb blue and red light, reflect

green/yellow Accessory pigments - absorb and

reflect other colors Can only be seen in the fall of the year

Photosynthesis

General Equation

CO2 + H2O --> C6H12O6 + O2

Major Steps1. Absorb light energy§ Convert light energy into chemical energy§ Store chemical energy in sugars

CO2 in, O2 out

Stomates open - gas is exchanged H2O is lost, must be replaced by roots

Transpiration - H2O diffusion out of plants

Light-dependent Reactions

Step 1: Absorb sunlight, split water and transfer energy through the H+

2 H2O 4 H+ + O2

“Electron Transport Chain via Photosystems I and II”

Step 2: Transfer energy to ATP

“ATP Synthase”

Light-independent Reactions

Step 1: CO2 is converted into larger molecules using ATP from Light-dependent reactions

Step 2: The larger molecules are converted into Glucose – C6H12O6

“Calvin Cycle”

Why Respiration?

Movement Transport in cells Maintenance Nervous Signals Biosynthesis

Respiration

Release of energy by breaking down glucose

1 Glucose = 38 ATPs!!!!!!

General Equation

C6H12O6 + O2 --> H2O + CO2 + ATP

Life has options…

Aerobic - Uses Oxygen! Animals Plants

Anaerobic - Little or no oxygen! Some animals Yeast Bacteria

Major Steps of Aerobic Respiration

Glycolysis Kreb’s Cycle Electron Transport Chain

Glycolysis

Simple step in the cytoplasm Makes 2 ATPs! Glucose is cut in half! Yields two Pyruvate molecules

(3 carbons each)

Kreb’s Cycle

Occurs inside the mitochondria Pyruvate molecules get broken into CO2

and H+ Makes 2 more ATPs!

Electron Transport Chain

Occurs on the cristae (membrane) of the mitochondria

H+ transfer excess energy to ATP synthase

Excess H+ + O2 H2O

ATP Synthase

Enzyme responsible for: ADP to ATP and O2 to H2O

Cellular Respiration

Electron transportchain and oxidativephosphorylation

Chemical energy

Chemical energy (high-energy electrons)

GlucosePyruvicacid

Glycolysis

Mitochondrialcristae

Cytosolof cell

Via oxidativephosphorylation

H2O

Mitochondrion

Krebscycle

CO2

CO2

ATPATPATP

Fermentation

When you undergo heavy exercise, you force your muscles to use fermentation!

Large amounts of Oxygen for Aerobic Respiration cannot be stored in cells

Cells need energy, so they choose the alternate route!

Can you function without O2?

Glycolysis yields 2 ATP Glycolysis does not require Oxygen

Yes you can!! You just get a little bit of energy

Anaerobic Respiration

Two types Lactic Acid Fermentation

Yeast and bacteria, your muscles Alcoholic Fermentation

Without fermentation, glycolysis would not continue

Fermentation recycles the molecules that allow glycolysis to continue

Fermentation

A build-up of lactic acid?

That must burn! It does until you recovery breath,

this is why your body breathes hard for several minutes after you stop exercising

You are making up for the oxygen loss

The replenishment of oxygen allows the cells to remove the excess lactic acid

Food Diary

Write down all of the foods you ate in the last 24 hours

Now, cross out…

Lactic Acid Fermentation

What would life be like without: Cheese, bread and yogurt?

Bacteria and Mold Convert milk into cheese Make yogurt go sour

Alcoholic Fermentation

Some yeast and plants Begins at the same point of lactic acid

fermentation Used to produce

Bread, beer and wine

Microbes in our Digestive System?

Bacteria in your digestive tract rely on fermentation

Without them we would not fully digest food They allow us to absorb more nutrients from

food

All cells need chemical energy.

Processes that make food include: Photosynthesis Chemosynthesis

Processes that make energy include: Respiration (two types) Fermentation (two types)