Warm Up #3 4/17

1. Why do we study “CHNOPS”?2. Which macromolecule has the most energy

(aka “long-term”) energy?3. Which type of macromolecules are enzymes?4. What do enzymes do?5. Which one of these is a macromolecule:

nucleic acid or fatty acid?

Agenda 4/17

• Photosynthesis Notes• Practice• Make sure to finish your assignment from

yesterday

Our big question for today

• How do organisms turn the sun’s energy into food energy?

• Learning target #3“I can explain how all living things get their

energy from the sun”

Making energy from the sun: From light to life

• Plants, algae, & bacteria use photosynthesis to turn light energy into chemical energy (food).

• Autotrophs: Organisms that can make their own food (from sunlight, heat, or chemicals)

Examples: plants, algae, some bacteria

• Heterotrophs Organisms that consume other organisms to get food are called

• Examples: humans, cows, grasshoppers, birds, fungi, amoebas

• KEY CONCEPT: all organisms on earth depend on the sun’s energy to live (either directly or indirectly)

Autotroph or heterotroph?

• Photosynthesis: Process where organisms use water, carbon dioxide, and energy from the sun to make glucose

Step 1: Light reactions (Trapping & converting the sun’s light energy)

• A. Sunlight enters a plant’s leaf cell and goes into the chloroplast (plant cell organelle)

• Inside the chloroplasts there are small compartments called thylakoids

(These compartments are surrounded by a liquid called stroma)

• Chlorophylls: special pigments in the thylakoid that trap light

• Chlorophylls only absorb certain light colors Chlorophyll absorbs blue & red light the best, but reflect green light—so plants look green!

B. With the help of an enzyme, the light is used to split water molecules

• Enzymes control the speed of photosynthesis

• Transpiration: loss of water in plants through their leaves

• Stomata: openings in the leaf (controls water balance & gas exchange)

Popcorn Questions

• Look through your notes• Come up with 1 question• Call on somebody to answer your question• They get to call on somebody else

C. Splitting water releases electrons and oxygen.

• The oxygen leaves the plant & goes into the air to get used by other organisms (remember: plants use oxygen too!)

D. The electrons are used to make molecules that store energy

• ATP (adenosine triphosphate): compound used by cells to store energy– ATP’s bonds get broken down forming ADP and

releasing energy

What have we done up till now?

Step 2: Dark Reactions (converting CO2 to glucose)

A. Carbon dioxide (CO2) enters the leaf through stomata

B. he carbon dioxide and hydrogens from water are turned into glucose using energy stored from the Light Reactions (Step 1)

C6H12O6

Photosynthesis Equation

• REACTANT: The chemicals that get changed in a reaction (what gets used)

• PRODUCT: The chemicals that get made in a reaction (what gets made)

• Energy is stored in the bonds of glucose**Energy stored in glucose can be used by the

plant or and animal that eats it!**

• What is the photosynthesis equation?– What does each part stand for?

• Using the chemical energy stored in glucose– What is glucose stored as?– What do plants use the energy from this for?

• Things that change the rate (speed) of photosynthesis– What are 3 things that can change the rate of

photosynthesis and how do they work?– Ex: More light = ________ photosynthesis

Return to our big question

• How do organisms turn the sun’s energy into food?

• Write your own answer to this in your notes & get it initialed by the teacher