Eat like a bird

1. Eat like a bird You 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)

2. Macromolecule Review • 4 major groups • Monomers & Polymers • Functions

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

4. 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.”

5. 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.

6. 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.

7. 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

8. 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.

9. Chemical Reactions • Chemical reactions are summarized by chemical equations • Example: 6CO2 +6H2O+sunlight energyC6H12O6 + 6O2 Reactants Products • Arrow is read as “changes to” or “forms”

10. Chemical Reactions • Chemical reactions can release energy or absorb energy (also see fig. 2-19 in text) Example: fossil fuel burning Example: photosynthesis

11. Chemical Reactions • Energy is needed to startchemical reactions; we call thisactivation energy • STOP: SUMMARIZE CHEMICAL REACTIONS in “Note Making” by yourself, then SHARE WITH LAB PARTNER

12. 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.

13. 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!

14. Enzymes

15. 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.

16. Enzyme Action

17. 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!