Transcript photsy-1

Photosynthesis and
Respiration
Why are these processes important?
•They provide the energy needed by all
organisms.
They maintain a constant amount of
oxygen and carbon dioxide in the
environment
Photosynthesis
 What are Its Raw
Materials?
What are its Products?
 Water which is absorbed by
the plants roots.
 Carbon Dioxide which is a
gas in the atmosphere that
passes through the stomata
of the plant’s leaves.
 Glucose – a sugar which
provides the energy cells need.
Oxygen – needed by most
organisms to perform respiration
Why is Photosynthesis
Important?
 It provides all organisms with glucose.
 The sugar, glucose, is the main source
of energy the cells need to carry out
important functions.
• It releases oxygen into the atmosphere.
Oxygen is needed by most organisms to
perform respiration.
What Kinds of Organisms
Perform Photosynthesis?
 Autotrophs are
organisms that can
make their own food
by performing
photosynthesis.
 Plants and some
algae are autotrophs
that perform
photosynthesis.
What Are the Two Stages
of Photosynthesis?
Stage One: Capturing the Sun’s Energy
Plants absorb the sun’s energy through the green pigment,
chlorophyll which is in the cells of their leaves. Chlorophyll
is found in the organelles called chloroplast.
What is the Second Stage
of Photosynthesis?
 Stage Two: Using energy to Make Food
The plants use the sun’s energy to produce
glucose and release oxygen.
The Photosynthesis
Equation
6CO2 + 6H2O
C6H12O6 + 6O2
What does the equation mean?
It means that:
6 molecules of carbon dioxide and 6 molecules
of water produce 1 molecule of glucose and 6
molecules of oxygen.
Respiration
 What are its Raw
Materials?
What are its
Products?
 Oxygen
 Glucose
Carbon Dioxide
Water
Energy
Why is Respiration
Important?
 Most organisms consume glucose as an
energy source.
 Cellular respiration is important because
it releases the energy that is contained in
the glucose molecules.
 Respiration breaks down the glucose
molecules into a form of energy the cells
can use.
What kind of Organisms
Perform Respiration
 Both Autotrophs and
Heterotrophs perform
respiration.
 Most organisms
need to perform
respiration in order to
release the energy
contained in the
glucose.
What Are the Two Stages
of Respiration
Stage One
 It takes place in the cytoplasm.
 The glucose molecules are broken down into smaller
molecules.
 No oxygen and very little energy is released for this
stage.
 It breaks down the glucose so that it is small enough to
enter the mitochondria.
Stage Two
 It takes place in the mitochondria
 The smaller glucose molecules are broken
down into even smaller molecules.
 Oxygen is required and a lot of energy is
released.
 Carbon dioxide and water is also released.
 Cells store and use the energy to carry out
their life processes
Comparing Photosynthesis
and Respiration
Photosynthesis
Its an energy making
process.
Its raw materials are
carbon dioxide and
water.
Its products are
glucose and
oxygen.
Respiration
Its an energy releasing process.
Its raw materials are
glucose and oxygen.
Its products are carbon
dioxide, water and
energy.
Opposite Processes
 Respiration and Photosynthesis are opposite
processes. Each process uses the other’s
products as its raw materials.
 In this way, photosynthesis and respiration
recycle carbon dioxide and oxygen in our
environment.
 This keeps the levels of these gases fairly
constant in our atmosphere.
Respiration Equation
C6H12O6 + 6O2
6CO2 + 6H2O + energy
It means 1 glucose molecule and
6 oxygen molecules yields or
produces 6 carbon dioxide
molecules , 6 water molecules
and energy.
What is Fermentation
 Fermentation provides energy for cells
without using oxygen.
 Organisms that live in environments that
contain no oxygen need to use
fermentation to release energy for their
cells to use.
What Are the Two Forms
of Fermentation?
Alcoholic Fermentation
Lactic-Acid
Fermentation
Alcoholic Fermentation
 Used by yeast and other single-celled
organisms.
 Its products are alcohol and carbon
dioxide.
 These products are used by bakers and
brewers.
Lactic-Acid
Fermentation
 Used by some organisms when oxygen in their
bodies have been used up too quickly. Ex.
Humans
 This process is used by most cells when
oxygen is not available and energy is needed.
 It produces lactic acid which causes muscles to
feel weak, sore and tired. Ex. A leg cramp
The End