1. Energy is
needed for:
Animals
Plants, (take up Every Organism
(Movement &
minerals, open & (Growth and cell
transportation of
close stomata). division).
things in body).
Energy is released by RESPIRIATION; this is the chemical
process that takes place in every cell, to keep it alive.
Respiration
1. Aerobic: - Respiration with the use of oxygen.
2. Anaerobic: - Respiration without the use of oxygen.
What Happens In?
1. Aerobic: -glucose is oxidised to give carbon dioxide and
water. Chemical Formula of reaction:
C6H12O6 + 6O2 6O2 + 6CO2 + 6H2O + energy
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2. Glucose + oxygenoxygen + carbon dioxide + energy
2. Anaerobic: -In anaerobic respiration, sugar is broken down
(with/o oxygen) into either ethanol or lactic acid is
released. A lot less energy is released in anaerobic
breakdown than in aerobic. Chemical Formula of reaction:
C6H12O6 - 2C2H5OH + 20C2 + Energy
Glucose  ethanol + carbon dioxide + Energy
How to measure the Rate of respiration:
You can use a respirometer, which measures the rate at which
oxygen is absorbed by organisms (i.e. their metabolic rate).
1) Compare the rate of respiration of different
organisms;
2)Find the effect of varying the temperature has
on the rate of respiration.
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3. How temp affects the rate of respiration
A rise of 10 degree’s approximately doubles the rate of respiration.
If it rises above 40 degree’s the rate of respiration quickly
decreases and stops.
This is because respiration is catalysed by enzymes.
Summary of Respiration:
Is the breakdown of food to release energy.
1) Yeast
2) Tapeworm
These organisms perform anaerobic respiration (they need no
oxygen however the oxygen speeds up the process).
C6H12O6 + 6O2 6CO2 + 6H20 + Energy
Glucose + oxygen  carbon dioxide + energy
^ is the simplest formula of the breakdown of food.
This process occurs in an organelle called the mitochondria which
is in the cells of every organism; without this organelle cells would
die.
--------- Next topic ---------- next topic ----------- next topic --------
Breathing
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4. Is the exchange of gases:
Air + 02  in
Extra air + CO2  out
When air goes in through the nose, cilia (the nose hairs) catch small
particles such as dust, smoke and other small, harmful particles stopping
them from getting into your lungs, thus making the air you breathe in safer.
Furthermore when you breathe in through your mouth does not have these
protections.
After inspiration (when air is drawn in through the mouth or nose) the
adenoids in the back of the nose and the tonsils at the back of the mouth,
work together to kill harmful micro-organisms.
Other benefits of breathing through your nose are the secretions from the
membranes in the nose which moisten the air so that it will not dry out the
air passages further down. All together when breathing in through the nose
you moisten, heat and clean the air you are breathing in, therefore making
it safer than breathing in through the mouth.
Main Structures in the Breathing System:
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5. Structure: Description and Function:
Nasal Cavity It is divided by shelves (turbinates) which warms, moistens,
cleans and tests the air breathed in.
Pharynx (throat) Point where the breathing and alimentary pathways cross.
Glottis Small hole through which air enters the larynx.
Epiglottis Flap which closes over the glottis during swallowing thereby
preventing food from going down it
Larynx Contains vocal cords which, when vibrated, make sounds.
Trachea Tube by which air passes to and from the lungs. Incomplete
Rings of cartilage to keep it open.
Bronchi Similar to Trachea, carry air to and from left and right lungs.
Bronchioles Narrow, tree like branches of bronchi through which gasses
diffuse to and from alveoli.
Alveoli Tiny air sacs across whose thin, moist walls gas exchange
takes place. Very close association with capillaries. The vast
number of alveoli provides a large surface area for gas
exchange.
Gaseous Exchange across the Alveoli.
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6. Alveoli.wmv
Gaseous exchange refers to the exchange of oxygen and carbon dioxide
between the air and the blood vessels surrounding an alveolus.
The walls of the alveoli are composed of a single layer of flattened
epithelial cells, as are the walls of the capillaries, so gases need to diffuse
through just two thin cells.
The alveoli walls are kept moist by water diffusing from the surrounding
cells. Oxygen dissolves in this water before diffusing through the cells into
the plasma, where it is taken up by haemoglobin in the red blood cells.
The water also contains a soapy surfactant which reduces its surface
tension and stops the alveoli collapsing.
Oxygen can diffuse down its concentration gradient from the air to the
blood, while at the same time carbon dioxide can diffuse down its
concentration gradient from the blood to the air.
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