Transcript Cells- Powerpoint

CELLS
CELLULAR COMPONENTS
& PROCESES
MODERN CELL THEORY
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The cell is the unit of structure and
function in living things.
All cells arise from preexisting cells.
The cells of all living things carry on
similar chemical activities.
All cells carry on their metabolic
activities in organelles.
There are two types of cells:
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2.
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Prokaryotic- cells that DO NOT have a
nucleus or other cell ORGANELLES
Eukaryotic- cells with a NUCLEUS &
cell ORGANELLES
Which is more complicated?
REMEMBER YOU ARE EUKARYOTIC!
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The parts of a cell that carry out a
function are called cell ORGANELLES:
All cells have the following
organelles:
Cell Membrane
 Cytoplasm
 Ribosomes
 Cytoskeleton
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Eukaryote cells ALSO have:
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Nucleus
Nucleolus
Mitochondria
Golgi Body Complex
Endoplasmic Reticulum
Vacuole
Lysosome
Centrioles (ANIMAL ONLY)
Only Plant Cells have all of the above &:
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Cell Wall
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Chloroplast
organelles
little “organs” of the cell
 Organelles are present in BOTH
plants and animals
 Carry out cellular functions!
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Nucleus
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cellular control center
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Controls cellular activity
contains hereditary material
(DNA in chromosomes)
 self duplicating structure divides when the cell divides
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Nuclear membrane
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surrounds nucleus allowing
certain materials to enter and
leave
Nucleolus
round organelle in the nucleus
 usually a pair
 involved with the synthesis of
RNA in the ribosomes
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Ribosomes
sites of protein synthesis in the
cytoplasm
 may be free in the cytoplasm or
attached to the endoplasmic
reticulum
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Endoplasmic reticulum (ER)
cytoplasmic channels from the
cell membrane to the nuclear
membrane
 associated with the storage,
synthesis, and transport of
materials within the cell
 “HIGHWAY” for cell transport
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Cytoplasm (protoplasm)
fluid like material between the
cell membrane and the nucleus
 over 80 % water
 “HOLDS” cell organelles in place
 site of most organelles and
cellular chemical reactions
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Vacuole
membrane bound cytoplasmic
spaces containing materials
 ** Vacuoles are crucial in singlecelled organisms
Two Types:
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Food vacuole--store and digest
ingested food
 Contractile vacuole-pumps excess
water from cells maintaining
homeostasis
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Lysosome
pouch containing digestive
enzymes
 digest bacteria and some foods
entering the cell
 Breaks down complex molecules
into simpler molecules (SLICE)
 breakdown worn out cell
organelles
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Mitochondrion
"Powerhouse of the cell"
 carries on cellular respiration
(contains respiratory enzymes that
make ATP) (energy molecule)
 may contain DNA--is self
duplicating-- divides when the cell
divides
 found in greater #s in active cells
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Golgi apparatus (complex)
usually located near the nucleus
 synthesizes, packages, and
secretes cellular products
 Packages waste & harmful
materials
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Plasma (cell) membrane
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The cell membrane is SEMI-PERMEABLE
selectively regulates the flow of materials
to and from the cell--thus maintaining
chemical homeostasis within the cell
The membrane acts like a BOUNCER only
allowing certain things in and out of the
cell It is made up of a lipid bilayer
double layer of FAT - "Fat sandwich"
transport through the plasma membrane
likely occurs through these globular
proteins (Fluid mosaic model)
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Hydrophilic- attracts water
Hydrophobic- repels water
Why is it important that the cell
membrane is made up of small
phospholipids?
ANIMAL CELL ORGANELLES ONLY
Centriole- a cylindrical structure
found in the cytoplasm which
appears to function during the
division of certain animal cells
(usually near the nucleus)
 Helps animal cells divide
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PLANT CELL ORGANELLES ONLY
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Cell Wall- a nonliving structure
which surrounds and supports the
cell - composed mostly of cellulose
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Gives the plant cell structure &
support
Chloroplasts- green in color-double
membrane - contain the green
pigment chlorophyll which carries
on photosynthesis
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Uses the sun’s energy to make food
for the plant
photosynthesis
the conversion of light energy to
chemical energy by chlorophyll
in chloroplasts
 Overall Net equation for
photosynthesis:
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6 Water + 6 Carbon dioxide yields
glucose + 6 oxygen (when
catalyzed by chlorophyll in the
presence of sunlight)
Levels of Tissue Organization
cell - unit of structure of all life
 tissue - composed of groups of
similar cells
 organs - composed of groups of
tissues functioning together
 organ systems - composed of
groups of organs functioning
together
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Types of transport in Cells
Passive transport - movement of
substances through a membrane
from a region of high to a region of
low concentration - no energy
needed (ATP) - diffusion and
osmosis are examples of this
 Active transport - movement of
substances through a membrane
from a region of low concentration
to a region of high concentration requires cellular energy (ATP)
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Whether passive or active transport
is needed depends on the
CONCENTRATION GRADIENT
The concentration gradient is the
difference in the concentration of a
substance in two different spaces
Concentration - the amount of a
particular substance in a contained
area compared with the amount of
the same substance in another area
Translation: Amount of something in
a space (water, salt, sugar, iron,)
PROCESSES OF THE PLASMA
MEMBRANE
There are two types of passive
transport: Diffusion and
Osmosis
 The goal of both diffusion and
osmosis is to reach
EQUILIBRIUM within the cell
 Equilibrium is a condition in
which the movement in one
direction is equal to the
movement in another direction
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Diffusion
the tendency of molecules to
move from an area of higher
concentration to an area of
lower concentration
 (concentration gradient- diff in
conc. between 2 regions)
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Osmosis
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movement of water through a membrane
from a region of higher to lower con.
Solute - substance being dissolved in a
liquid (ex. salt)
Solvent - substance doing the dissolving
(ex. water)
Permeability - the extent to which a
membrane will allow particular sized
molecules to pass
Semi-permeable membrane (selectively
permeable)-allows some molecules to pass
but not others
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So, describe how “Kool-Aid”® is
made with regard to the terms
“solute” and “solvent”. What is the
“universal solvent”?
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When comparing two solutions there are
three possible relationships, We Identify
the relationships by determining what
would happen if a cell were placed in the
solution.
Hypertonic- A solution that causes a
cell to shrink because of osmosis.
Meaning water leaves the cell.
Hypotonic- A solution that causes a cell
to swell because of osmosis meaning
water rushes into the cell.
Isotonic-A solution that causes no
change in cell size. Meaning there is no
movement of water.
If the fluid outside
the cell has…
…less water than is
present inside the cell
…more water than is
present inside the cell
…same amount of
water as inside the cell
Then the outside
fluid is…
Water moves…
Effect on the cell?
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So, answer this question…. Why do
“establishments” offer free popcorn,
peanuts, and pretzels to their
patrons if they are serving
beverages? What changes are
taking place in the body to initiate
the need for more beverages?
Active Transportthe movement of a substance
against the concentration
gradient. (uphill)
 Active transport requires cell to
USE ENERGY
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Sodium pump - transports three
sodium ions out of the cell and
two potassium ions into the cell
Both are against the
concentration gradient
The energy needed to perform
this activity is supplied by ATP
(adenosine tri-phosphate)
ATP is a unit of energy made by
the cell
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Endocytosis- the movement of a
substance into the cell by a vesicle. A
vesicle is a form of packaging that is
used by cells.
Exocytosis- the movement of a
substance out of the cell by a vesicle.
Phagocytosis- cytoplasm of cell
surrounds and engulfs particle--ex.
ameba and white blood cell
Pinocytosis- plasma membrane
"pinches in" to permit entry of molecules
too large to diffuse through