ENERGY FOR LIFE
Trapping and Using Energy

Metabolism
 The
total of all chemical reactions in an organism
 The chemical reactions of metabolism need enzymes
 Enzymes
help cause the chemical reaction to take place
 The enzyme is not changed by the chemical reaction
 Enzymes are reusable
Photosynthesis

Producers
 Organisms
that can produce their own food
 Use the energy from sunlight to produce sugar
 Usually green organisms (contain chlorophyll)

Consumers

Organisms that cannot produce their own food
Photosynthesis

Energy from the sun is used to drive chemical
reactions to produce sugar
carbon dioxide + water
sugar + oxygen
(raw materials) (enzymes)
(products)

In plants, the raw materials come from the soil and
air.
Storing Carbohydrates

Plants make more sugar during photosynthesis than
they can use at the time.
 Changed
into starch and stored
 Used to make other types of carbohydrates
Carbohydrates

Plants use carbohydrates for:
 Growth
 Maintenance
 Reproduction
Consumers

Why is photosynthesis important to consumers?
 Consumers
take in food by eating producers
or other consumers
 Photosynthesis is involved directly or
indirectly in producing food for consumers
Respiration





Chemical reactions that break down food into
simpler substances that can be used by the cell
Uses oxygen to break down the food
Stored energy is released when the food is broken
down
Enzymes are needed for respiration
Occurs in all living cells
Breaking Down Carbohydrates


Carbohydrates are the easiest food to break down
Respiration takes place in the cytoplasm of the cell
 Carbohydrates
are broken down into glucose
molecules
 Glucose is further broken down into simpler
substances
Breaking Down Carbohydrates

Those simpler substances are then transported to the
mitochondria
 Those
substances are further broken down
 More energy is released
 Produces carbon dioxide and water as waste
products
Fermentation



Takes place when there is not enough oxygen for
respiration to occur
Chemical reactions occur in the cytoplasm only
Produces some energy and waste products
 Lactic
acid
 Alcohol
 Carbon dioxide
Fermentation

Some microorganisms use fermentation
 Produce
yogurt
 Some cheeses

Yeasts
 Breaks
down sugar in bread
Carbon dioxide (makes the bread dough
rise)
Alcohol
Related Processes

Comparing photosynthesis and
respiration/fermentation
 What
is produced in one process is used in
the other process to produce energy
 The two processes are almost opposite of
each other
Related Processes

Photosynthesis
 Produces
sugar and oxygen
 These products used in respiration

Respiration
 Produces
carbon dioxide and water
 These products used in photosynthesis