DO NOW:1. What is energy?2. What requires energy?3. How do cells obtain energy?

• Energy is defined as the ability to do work

• There are two main forms of energy– Potential and Kinetic

Energy and Thermodynamics

Two main categories of energy

Stored energy is called Potential energy

Energy has the “potential” to do work if released

Motion energy is called Kinetic energy

Energy which is being released and actively doing work

Energy and Thermodynamics

• Energy has many forms

– Chemical (glucose, ATP)

– Thermal (heat)

– Radiant (sun)

Energy and Thermodynamics

Energy is NOT created or destroyed, it can only be changed from one form to another

http://www.videopediaworld.com/video/23610/Compound-Machines-The-Law-Of-Conservation-Of-Energy

BUT energy does “flow” to a point where the energy is converted to an unusable form (heat)

Light Glucose ATP Heathttp://www.scivee.tv/node/5583

How is Matter “Changed” or rearranged in living things?

MetabolismALL the biochemical reactions in cells

used to obtain OR use energy (both building and breaking)

Breaking down foodBuilding bone and muscleGrowingRepair (healing)Cleanup (from an infection)

ANABOLISM - building

Plants can take CO2 and H2O and turn them into glucose.

All organisms can make proteins from amino acids

Joining small things together to make bigger things is called ANABOLISM. Metabolic reactions that use energy

Energy is used to do this

Catabolism – breaking down

Animals often need to breakdown matter into smaller parts in order to absorb the matter into their cells.

Plants (and embryos) need to break down stored starch and lipids for energy

Enzymes breakdown dead/decaying material.

This is called CATABOLISMMetabolic pathways which break down

Ultimate Source of Energy

Matter is changed many timesFusion happens in the sunH He other elements

Released energy (Electromagnetic energy (radiation)

Plants convert EM energy to chemical energy (glucose)

What is ATP (Adenosine Tri-Phosphate)?• The only molecule cells can use to do

work in living things:

Adenine Ribose 3 Phosphate groups

Basically a Nucleotide with two extra phosphates!

What’s the deal with ATP?

• Energy molecule for life

• Hydrolyzing (breaking off) third phosphate frees energy which can be used to do work in the cell

• ADP (what is left) can be recycled.

What’s the deal with ATP

• To recycle ADP back to ATP, the cell uses energy from glucose to add a 3rd phosphate

• ATP is made again

ADP and ATP

ADP/ATP cycle

Electron Carriers

• Molecules that “pick up” high energy electrons and carry them until their energy is needed elsewhere.

• Examples : NADH (CR); FADH2 (CR)

• NADPH

NADHFADH2

NAD+FAD

e-

to charge ATP

from glucose

e-

NADPH NADP+

e-

to make glucose

From sun

e-

ENERGY FLOW AND LIFE

Electromagnetic Spectrum

• Energy can travel in vibrations or waves.

• Different types of energy have a different number of vibrations per period of time.

• This is called frequency.

• Scientists organize waves according to their frequency or wavelength in the electromagnetic spectrum.

Light Energy

• Sunlight sometimes called white light, is a form of energy that we can see and it travels in waves.

• Wavelength: the distance between the crest of one wave and the crest of the next wave

Visible Light Spectrum

• Depends on wavelength

• Blue: 380 (nm)

• Green: 500 (nm)

• Yellow 560 (nm)

• Light red: 600 (nm)

• Darker red: 750 (nm)

1600s: Jan van Helmont

• Grew a small willow tree and only added water to the plant.

• After five years the tree gained 75 kg, but the soil had the same mass.

• Where did the new plant material come from?

1770s: Joseph Priestley

• Placed a plant in a closed container with a candle.– “damaged air”

• Candle will go out and animals cannot live under these conditions.

• Plants can live and restore the ability of the air to support a flame and an animal.

• How do plants interact with air?

A few years later…• Antoine Lavoisier

–Oxygen removed from air during burning

•Animals need oxygen to survive.

•What about plants?

Other discoveries in the 1700s…

• Jan Ingenhousz– Plants only give off oxygen in sunlight

• Jean Senebier– Plants take in carbon dioxide during growth in

sunlight

1800: Requirements for Plant Growth Determined

• Carbon dioxide

• Water

• Light

Plant Nutrition

Photosynthesis

• Process of capturing energy of sunlight and transforming it into chemical energy

Equation for Photosynthesis

Light + CO2 + H2O--glucose + O2

Autotrophs

• Organisms that are capable of making food from simple inorganic substances

• EX: green plants, algae

Two Types of Autotrophs

• 1. Photoautotrophs: use carbon dioxide and light energy to drive reactions needed to make food

• 2. Chemoautotrophs: utilize inorganic chemicals for the energy to drive food making reactions

Heterotrophs

• Organisms that cannot make their own food and must depend on other plants or animals as food source

• Examples: ___________

PIGMENTS

• Pigments: absorb light

• EX: a red object absorbs all the visible colors of the spectrum except red which is reflected and gives the object the red color

CHLOROPLAST

Organelle that contains photosynthetic pigments that

absorb light energy

Types of Photosynthetic Pigments

a. Chlorophyll: appear green absorbs red and blue light

b. Carotenes: appear orange

c. Xanthophylls: appear yellow

CHLOROPLAST

• Site of Photosynthesis• Found in what type of cells?

Parts of the chloroplats: THYLAKOID

• contains photosynthetic pigments; flattened membrane sacs

Grana

• Stacks of thylakoids

Stroma

• Fluid region between grana–Contains DNA, ribosome, starch

grains• Why do chloroplasts have their own DNA?