Eat like a birdYou hear it about people who don’t eat much. People say they “eat like a bird.” Yet birds eat a larger proportion of their weight every day than even the heartiest human eaters.

Birds eat a high-energy diet of seeds, fruit, worms, insects, fish or meat---maximum energy, minimum bulk. Digestion is fast and thorough.

Food energy is spent in flight, in keeping warm-----in simply being a bird.

What is the relationship between an animal’s metabolism and the amount of food it eats? Use a comparison between birds and humans in your answer. (look in your glossary for the word metabolism)

Macromolecule Review

• 4 major groups

• Monomers & Polymers

• Functions

Macromolecule Review

• For each macromolecule name the monomer and give the function of each macromolecule.

Crackers? Hmmm…so sweet.• When the 1st cracker is given to you, place

it in our mouth, chew it and swallow it. Do this relatively quickly, as you normally would eat crackers.

• As you chew, describe how it tastes and feels as you chew it and swallow it.

• Record these observations on the index card under the title: “Cracker…Fast Chew.”

• After recording observations, make a new title below called: “Cracker…Slow Chew.”

Concept: Enzymes

• Lesson Essential Question: How would a change in enzyme activity affect a living system?

• To understand enzymes, we have to understand basic chemistry including chemical reactions and how living things use macromolecules to chemically obtain energy for life’s functions.

Chemical Reactions & Life

• Metabolism is all of the chemical reactions that occur within an organism.

• Your cells get energy needed for metabolism from the food you eat.

• Chemical energy is converted into a useable form.

Types of Chemical Reactions

• Extracting matter and energy from the environment

• Transporting various chemicals

• Synthesizing new biomolecules

• Moving the cell or organism within it’s environment

• Replicating the parent cell

Chemical Reactions

• Energy is stored or released by chemical reactions

• Bonds are broken and new bonds formed between atoms

• Different substances can be produced• Reactants are the starting materials for

chemical reactions• The newly formed substances are called

products.

Chemical Reactions

• Chemical reactions are summarized by chemical equations

• Example: 6CO2 +6H2O+sunlight energyC6H12O6 + 6O2

Reactants Products

• Arrow is read as “changes to” or “forms”

Chemical Reactions

• Chemical reactions can release energy or absorb energy (also see fig. 2-19 in text)

Example: fossil fuel burning Example: photosynthesis

Chemical Reactions

• Energy is needed to start chemical reactions; we call this activation energy

• STOP: SUMMARIZE CHEMICAL REACTIONS in “Note Making” by yourself, then SHARE WITH LAB PARTNER

Back to: Crackers? Hmmm…so sweet.

• When you get your second cracker, place it in your mouth (or just take a bite) and this time chew it very slowly and hold the crumbs in your mouth.

• Allow the cracker to be in your mouth for 2 minutes, carefully chewing it.

• record observations in the “Cracker…Slow chew” part of your note card.

Enzymes

• All reactions need energy to start…called activation energy

• Catalysts are substances that speed up the rate of chemical reactions

• Enzymes are proteins that act as biological catalysts, greatly speeding up reactions in cells.

• Allows reactions to occur at much lower temperatures than normal…important for living things!

Enzymes

Enzymes, cont.

• Enzymes work because they provide a site where reactants can interact.

• The reactants in this case are called substrates• Figures 2-21, 2-22 in text show how substrates

bind to the active site on the enzyme, react and then the products are released.

• Released products are things cells need to function… molecules big and small, regulating metabolism, releasing energy, etc.

Enzyme Action

Enzyme Reactions

• STOP: SUMMARIZE Enzymes in “Note Making” by yourself, then SHARE WITH LAB PARTNER

• On the BACK of your index card, write your answer to the lesson essential question … make an inference!