Eat like a bird

1
Eat like a bird
You hear it about people who dont 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 animals 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
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 lifes functions.

4
Chemical Reactions Energy

• 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.

5
Chemical Reactions

• Chemical reactions are summarized by chemical
  equations
• Example
• 6CO2 6H2Osunlight energy?C6H12O6 6O2
• Reactants ?Products
• Arrow is read as yields or forms

6
Chemical Reactions

• Chemical reactions can release energy or absorb
  energy (also see fig. 6-15 6-16 in text)

Example photosynthesis
Example fossil fuel burning, respiration
7
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.

8
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

9
Enzymes

• All reactions need energy to startcalled
  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 normalimportant for living
  things!

10
Enzymes
11
Enzymes, cont.

• Enzymes work because they provide a site where
  reactants can interact.
• The reactants in this case are called substrates
• Figure 6.18 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.

12
Enzyme Action
13
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!