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CELLS
The smallest structural unit of an organism that is capable of
independent functioning
TRAFFIC IN AND OUT OF CELLS
LIFE PROCESSES INVOLVED:
MOVEMENT
INGESTION
EXCRETION
In Nature:
 All matter is made up of tiny particles:
molecules
 Molecules are always moving
 Molecules always move or spread out evenly
DIFFUSION
 Defined as movement of molecules from a “crowded” or a
concentrated area to a “less crowded” or lower
concentrated area.
 Materials enter/leave living cells through the natural
process of diffusion
REQUIREMENTS FOR DIFFUSION IN/OUT
OF CELLS
1. Membrane:
 Must be selectively permeable - only certain things
can pass through (in/out)
2. Water
 material must be dissolved in water
3. Size
 Material must be small enough
4. Direction
 From concentrated section to less concentrated section
“crowded”
“less crowded”
OSMOSIS
Osmosis is a special case of diffusion..
it is diffusion of pure water
ACTIVE TRANSPORT
 Defined as movement of materials from a
less concentrated area to a more concentrated area.
 It is the opposite of diffusion
 It needs ENERGY for “pumping”.
CELLULAR RESPIRATION
 set of metabolic reactions and processes
 Respiration is one of the key ways a cell gains useful energy to fuel
cellular reformations
Paper + O 2
Energy +
(heat and light)
Carbon dioxide and water (H 2 O)
Wood + O 2
Energy +
(heat and light)
Carbon dioxide and water (H 2 O)
Gas + O 2
Energy +
Carbon dioxide and water (H 2 O)
(heat and light)
Food + O 2
Energy +
(heat and light)
Carbon dioxide and water (H 2 O)
BURNING
 When any material combines with oxygen it will release:
ENERGY
WASTES
heat
carbon dioxide CO 2
water H 2 O
light
burning is fast and furious ….. uncontrolled
RESPIRATION
 Defined as a series of chemical reactions by which energy is
released from food (sugar) in the presence of oxygen.
 There are two types: _____________ and ______________
AEROBIC
WITH Oxygen (O 2 )
ANAEROBIC
WITHOUT Oxygen (O 2 )
A. Equation for Aerobic respiration
Digested food + Oxygen = Energy + Carbon dioxide & water
fuel
(O 2 )
Heat
waste
B. Occurs in mitochondria
Respiration is calm and controlled
Controlled by special proteins
called ENZYMES.
Digested food + Oxygen
Food you eat
air you
Breathe
=
Energy +
1. body temp
2. 8 life processes
CO /H O
2
2
exhale
sweat
ANAEROBIC RESPIRATION
 Defined as the release of energy from food without using
oxygen
 also called FERMENTATION
A. Anaerobic respiration:
- releases less energy
- uses no oxygen
- occurs only in certain yeast and bacteria
- produces acids, alcohol and CO 2 as waste products
B. Products used by humans from the process of fermentation
Acids
Alcohols
CO 2
Yogurt
Cheese
Sauerkraut
Vinegar
wine
beer
bread dough