Title: 3.2%20Energy%20for%20Life
13.3 Energy for Life
2Where do these guys get the energy they need to
play basketball ?
- Metabolism Enzymes
Thats 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.
3ALL activities of an organism involve chemical
reactions in some way.
2 H2 O2 --gt 2 H2O
This is called Metabolism-the total of all
chemical reactions in an organism.
4All 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.
5Organisms can be divided into 2 groups
B. Photosynthesis
producers-organisms that can make their own food
consumers-organisms that cannot make their own
food
6Photosynthesis(how energy is trapped)
Producers harness sunlight energy to make their
own food!
7How 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 6CO2 ----------gt C6H12O6
6O2 water carbon dioxide yields
glucose oxygen
8So, taking it slowly.
Plants take sunlight energy into their leaves.
9Plants take CO2 (carbon dioxide) from the
atmosphere into their leaves.
Glucose is formed by photosynthesis
10They take in H20 (water) through their roots.
11A chemical reaction takes place with the help of
enzymes..
Fortunately, we dont have to get into the
chemistry of that for now..
12So 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!
13What 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.
14Why is Photosynthesis important to you?
Photosynthesis
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?
VEGETABLES?
MEAT?
15Do you eat ANYTHING?
ANYTHING
16Anything you eatcan be traced backto a
PRODUCERwhich can betraced backto the SUN!
17 The SUN is the source of all food energy on
Earth!
18If the plants make glucose using the suns
energy, then how do WE use it for fuel?
19C. 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?
22Glucose 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
23So, 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!
24D. Fermentation
When cells dont have enough oxygen for
respiration, they use a process called
fermentation to release some of the energy stored
in glucose molecules.
25Like respiration, 1. Fermentation begins in
the cytoplasm.2. Glucose molecules are broken
down, energy is released.3. More chemical
reactions occur in the cytoplasm, releasing
energy and producing wastes.
26Your muscle cells use fermentation to change
simple molecules into lactic acid while producing
energy, often making yourmuscles stiff and sore!
Going for the BURN!
27BACTERIA use fermentation to break down a sugar
in milk-the lactic acid gives foods like yogurt
and cheeses their flavor.
28And 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!
29And so we see that the elegantly simple, yet
dazzlingly complex, processes of photosynthesis
and cellular respiration make up another of
thewonderful cycles of nature. The products of
one process are the necessary reactants for the
other and so it goes
Yield the O2 and glucose necessary for cellular
respiration to occur!
CO2 from the atmosphere water from the water
cycle sunlight energy