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There are more than 120 elements-25 are
needed for life
Water is needed for chemical reactions. About
2/3 of every cell is water
Many form the 4 basic molecules for life
◦ Carbohydrates-sugar and starch used for quick
energy
◦ Lipids-fats, oils and waxes needed for stored energy
◦ Proteins- for the growth and repair of tissues and to
fight infections
◦ Nucleic Acids-DNA and RNA that have instructions
for everything-especially reproduction
a. All cells need energy. Chemical energy is stored
in the bonds of molecules like glucose.
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A process used by plants and other autotrophs to
convert the energy of sunlight into sugars.
It requires sunlight, water, and carbon dioxide.
It occurs in the leaves of plants in organelles called
chloroplasts.
WATER
6CO2 + 6H2O +ENERGY
CARBON
DIOXIDE
OXYGEN
C6H12O6 + 6O2
GLUCOSE
c. Cells release energy in two ways
1. Cellular Respiration-cytoplasm and
mitochondria converts glucose into
energy, CO2 and water
2. Fermentation-allows cells to release
energy without oxygen
a. Alcoholic fermentation- makes alcohol
b. Lactic Acid fermentation- makes
lactic acid; milk , cheese and sore
muscles
GLUCOSE
CARBON
DIOXIDE
C6H12O6 + 6O2
6CO2 + 6H2O +
OXYGEN
WATER
ATP
ENERGY
*Photosynthesis and Cellular Respiration are opposite
processes
a. Certain things MUST enter the cell for it to
survive. This can occur in 2 major ways:
1. PASSIVE TRANSPORT -requires no
energy
2. ACTIVE TRANSPORT-requires energy
7
1.
2.
3.
Oxygen
Carbon
dioxide
Water
8
Cell membrane
Inside cell
Outside cell
9
Cell membrane
diffusion
Inside cell
Outside cell
10
Cell membrane
Inside cell
Outside cell
EQUILIBRIUM
11
12
High H2O potential
Low solute concentration
Low H2O potential
High solute concentration
13
14
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The movement from lower concentration to higher
concentration
Active transport requires the use of energy
2 ways that materials are moved
1. Endocytosis -very large molecules are brought into the
cell
2. Exocytosis-materials are moved out of the cell (usually
wastes)
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Temperature
Size of materials
Surface area of a cell*
Volume*
*The surface area can sometimes increase
faster than the volume or the cell’s ability to
hold materials so it stops growing
Cell Shape
1. Cells need four large molecules to function:
Carbohydrates, lipids, proteins and nucleic acids.
2. 2/3 of all cells are water
3. Cells capture energy through photosynthesis and
release energy through cellular respiration and
fermentation
4. Materials are moved from areas of high
concentration to low concentration through passive
transport that does not require energy. Diffusion
and osmosis are examples.
5. In active transport, energy is required to move
materials from areas of low concentration to high
concentration. Endocytosis and exocytosis are
examples
6. Things that affect transport are: shape, size,
volume, surface area, material size and temperature