Download Cell Processes and energy

CELL PROCESSES
AND ENERGY
Cells
Unit 2, Part II
H. Carter
ELEMENTS AND COMPOUNDS
 Elements


Any substance that cannot be broken down into simpler
substances
 Smallest unit= atom
Carbon, hydrogen, oxygen, nitrogen, phosphorus,
sulfur= found in living things
 Compounds

Two or more elements that are chemically combined
Smallest unit= molecule
 Water

two-thirds of your body
 most chemical rxns w/in cell take place when
dissolved water
 help cells keep size and shape
 keeps cell from changing temperature too rapidly


Inorganic compound

Do not contain carbon

Water, sodium chloride (table salt)
Organic compounds

Contain carbon

 Carbohydrates
•Made of carbon, hydrogen, and oxygen
•Sugars and starches
•Energy
•Found in cell walls, cell membranes
 Lipids
• Made of carbon, hydrogen, and oxygen
•Fats, oils, waxes
•Energy-rich (more than carbs) for later
use
 Proteins
•Made of carbon, hydrogen, oxygen,
nitrogen, and sometimes sulfur
•Meat, fish, eggs, nuts, beans
•Made of amino acids
•Enzyme- speeds up or slows down a
chemical rxn
 Nucleic
Acids
•Made of carbon, hydrogen, oxygen,
nitrogen, phosphorus
•Contain instructions for cell
DNA (deoxyribonucleic acid)- genetic
material, directs all cell functions; found in
chromatin
 RNA (ribonucleic acid)- role in production of
proteins; found in cytoplasm and nucleus

CELL TRANSPORT
*Cell membrane is selectively permeable
which means that certain things can pass
w/in the cell while others cannot
Diffusion

Process by which molecules move from
an area of greater concentration to
lesser concentration (high to low)
Molecules are always moving and collide
with each other
 Collisions cause the molecules to move
away from each other to more open space

Osmosis
Diffusion of water molecules through a
selectively permeable membrane
 Because cells cannot function properly
w/out adequate water, many cell
processes depend upon osmosis
 V:\hcarter\Cell
Processes\Diffusion_and_Osmosis.asf

Normal red blood cell
High water concentration
Low water concentration
outside cell
outside cell
 Passive
Movement of materials through the cell membrane
that does not require cellular energy
 V:\hcarter\Cell Processes\Passive transport
4.00.asf
Active Transport
 Movement of materials through the cell membrane
using cellular energy
 Low to high (lesser concentrated to greater)


Transport

Methods of Active Transport

Transport Proteins


proteins in the cell that “pick-up” molecules
outside cell and carry them in or molecules inside of
cell and carry them out
Engulfing

cell membrane surrounds and encloses a particle
*Cells are the small size that they are in order
for them to have an easier job in doing their
jobs
V:\hcarter\Cell Processes\Active transport
5.33.asf
PHOTOSYNTHESIS
Process by which a plant captures energy from
the sun and uses it to make food
 Nearly all living things obtain energy either
directly or indirectly from the sun


Stage 1

Capturing the sun’s energy
Green pigments in chloroplasts called chlorophyll absorb
sunlight
 In plants, mostly occurs in the leaves

 Stage

2
Using energy to make food
Cell uses the captured energy to make sugars
 Needs water and carbon dioxide to do this (reactants)
 Produces a sugar and oxygen (products)

light energy
6 CO2 + 6 H2O
Carbon dioxide
water
C6H12O6 + 6 O2
a sugar
V:\hcarter\Cell Processes\Photosynthesis.asf
oxygen
CELLULAR RESPIRATION
Process by which cells obtain energy from glucose
 Cells break down simple food molecules such as
sugar and release the energy they contain


When cells need energy, they “withdraw” it by
breaking down the carbs in the process of respiration
 Stage




1
Takes place in the cytoplasm
Molecules of glucose are broken down into
smaller molecules
Oxygen is not involved
Small amount of energy released
 Stage





2
Takes place in the mitochondria
Small molecules are broken down into even
smaller molecules
Requires oxygen and releases a large amount
of energy
Uses sugar and oxygen (reactants)
Releases carbon dioxide, water, and energy
(products)
C6H12O6 + 6 O2
sugar
oxygen
6 CO2 + 6 H2O + energy
carbon dioxide
water
V:\hcarter\Cell Processes\Cellular_Respiration.asf
COMPARING PHOTOSYNTHESIS AND
CELLULAR RESPIRATION
They are OPPOSITES!
FERMENTATION
 An
energy releasing process that does not
require oxygen
Provides energy for cells
 Energy release is much lower than for
cellular respiration

Alcoholic Fermentation: occurs when yeast and
other unicellular organisms break down sugars
 Bakers, brewers
 Lactic Acid Fermentation: occurs in muscles when
your muscle cells use up oxygen faster than it can
be replaced


Product is lactic acid; causes pain, soreness