1. 3.3 Energy for Life

2. Where do these guys get the energy they need to play basketball ?
Metabolism & Enzymes
Where do these guys get the energy they need to play basketball ?
That’s right-from the food they eat!
The chemical energy stored in food is changed in cells into forms needed by organisms to carry on life activities.

3. ALL activities of an organism involve chemical reactions in some way.
2 H2 + O2   -->   2 H2O
                                                
This is called Metabolism-the total of all chemical reactions in an organism.

4. All chemical reactions need
ENZYMES-
proteins which speed up chemical reactions by
bringing molecules together or breaking them apart.
-Enzymes are REUSABLE-they
are not changed by the reactions
they cause-like
1. a stapler that
hooks things together or
2. a can opener that takes things apart.

5. Organisms can be divided into 2 groups:
B. Photosynthesis
Organisms can be divided into 2 groups:
producers-organisms that can make their own food
consumers-organisms that cannot make their own food

6. Photosynthesis (how energy is trapped)
Producers harness sunlight energy to make their own food!

7. How Photosynthesis Works
Plants take in sunlight energy using chlorophyll in the chloroplasts of their leaves.
Plants take carbon dioxide (CO2) from the atmosphere into their leaves.
Plants take in water (H2O) through their roots (it comes in from the soil)
Plants release oxygen (O2) into the atmosphere. (and it is then used by consumers for cellular respiration
Glucose is formed (C6H12O6) and is used by producers and consumers for fuel.
6H2O CO > C6H12O O2
water + carbon dioxide yields glucose oxygen

8. So, taking it slowly…….
Plants take sunlight energy into their leaves.

9. Glucose is formed by photosynthesis
Plants take CO2 (carbon dioxide) from the atmosphere into their leaves.
Glucose is formed by
photosynthesis

10. They take in H20 (water) through their roots.

11. A chemical reaction takes place with the help of enzymes…..
Fortunately, we don’t have to get into
the chemistry of that for now…..

12. Will you have to memorize this equation? YES you will!
So now WHAT Is Photosynthesis?
Photosynthesis is a chemical reaction used by plants and some bacteria to use the energy from sunlight to produce glucose (sugar). In plants it is the chlorophyll in the leaves that converts the rays from sunlight into chemical energy.
Will you have to memorize this equation? YES you will!

13. What does all of this have to do with ENERGY FOR LIFE?
Plants make more GLUCOSE (sugar) during photosynthesis than they need for their survival-excess sugar is changed and stored as starches or used to make other carbohydrates.

14. Why is Photosynthesis important to you?
Do you eat kiwi?
Do you eat bananas?
Do you eat oranges?
Do you eat strawberries?
Do you eat grapes?
Do you eat blueberries?
BREAD?
Do you eat eggs?
Do you eat cheese?
Do you drink milk?
MEAT?
VEGETABLES?

15. Do you eat ANYTHING?
ANYTHING

16. Anything you eat can be traced back to a PRODUCER which can be traced back to the SUN!

17. The SUN is the source of all food energy on Earth!

18. If the plants make glucose using the sun’s energy, then how do WE use it for fuel?

19. C. Cellular Respiration
Cellular respiration is the process by which the chemical energy of "food" molecules is released and made available in the form of ATP.
                           
                                       
               

20.                                                                   
glucose
    2 pyruvic acid molecules
Cellular respiration starts in the cytoplasm with glycolysis, which breaks down glucose into 2 molecules of pyruvic acid. It does not need oxygen as part of any of its chemical reactions.

21. OK, so energy is stored in GLUCOSE, but how do we get energy from the food we EAT?

22. Glucose is broken down in the CYTOPLASM into 2 molecules of pyruvic acid.
Water is released through urination, perspiration & exhalation
And
Oxygen is taken in by the lungs and delivered by the bloodstream
CO2 is
released
by exhalation for plants to use in
Cellular respiration finishes up
in the cytoplasm and energy is
released.
photosynthesis

23. So, what about sprinters
So, what about sprinters? They run out of O2 before the end of the race-what gives them the strength to keep going-how can they convert glucose to energy without O2?
Coming up next…… Fermentation!

24. D. Fermentation
When cells don’t have enough oxygen for respiration, they use a process called fermentation to release some of the energy stored in glucose molecules.

25. Like respiration, 1. Fermentation begins in the. cytoplasm. 2
Like respiration, Fermentation begins in the cytoplasm Glucose molecules are broken down, energy is released More chemical reactions occur in the cytoplasm, releasing energy and producing wastes.

26. Going for the BURN!
Your muscle cells use fermentation to change simple molecules into lactic acid while producing energy, often making your muscles stiff and sore!

27. BACTERIA use fermentation to break down a sugar in milk-the lactic acid gives foods like yogurt and cheeses their flavor.

28. And finally, YEASTS use fermentation to break down sugar in bread dough.
Alcohol and CO2 are produced as wastes. The CO2 causes the bread to rise and the alcohol is lost as the bread bakes!

29. Yield the O2 and glucose necessary for cellular respiration to occur!
CO2 from the atmosphere + water from the water cycle + sunlight energy
And so we see that the elegantly simple, yet dazzlingly complex, processes of photosynthesis and cellular respiration make up another of the wonderful cycles of nature. The products of one process are the necessary reactants for the other and so it goes……