Download Cell Structure and Function

Warm Up:
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What are the three parts of cell theory?
All organisms are composed of cells
The cell is the structural unit of life
Cells arise only from previously existing
cells
Cell Theory
The Microscope
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Dutch lens grinder
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Invented the first
compound microscope
around 1600
The “CELL”
Robert Hooke 1635-1703
• Observed cork under
microscope-1655
• Noted many chambers
that he called “cells”
• Publishes
Micrographia
Anton van Leeuwenhoek
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Designed his own
microscope- 1683
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Discovered single
celled protozoan
The Cell Theory
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1830- German scientists Schleiden and
Schwann develop Cell Theory
All organisms are composed of cells
The cell is the structural unit of life
Cells arise only from previously existing
cells
Henri Dutrochet
"The cell is the fundamental element of
organization"
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In 1858, Rudolf Virchow concluded that
all cells come from pre-existing cells thus
completing the classical cell theory.
Cell Types
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Prokaryotic
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Eukaryotic
1.
“before nucleus”
No membrane bound
organelles
Lacks nucleus
Most unicellular
organisms are
prokaryotic
Monera
1.
“true nucleus”
Membrane bound
organelles
Contain nucleus
Most organisms are
made of these cells
Plant cells, human
cells
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Cell Types
Organelles
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Specialized part of the cell
“little organs”
Animal Cell
Plasma or cell
membrane
1. Forms a thin, flexible boundary between a cell and
its environment
2. Selectively permeable
-Allow some substances to pass through while
keeping others out
Plasma membrane
Phospholipid
bilayer
 hydrophilic
head-water loving
 Hydrophobic tailwater fearing
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Plasma membrane-other
components
Moving with and
among phospholipids
1.Proteins
2.Carbohydrates
3.Cholesterol
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“Fluid mosaic”- bilayer
creates a sea in which
these molecules can
move around
Plasma membrane
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Proteins
1.
Receptors- proteins on outer surface that serve to
transmit signals to inner cell
Structural-proteins on inner surface that serve to
anchor the plasma membrane to the inner cell
Transport- proteins that span the entire
membrane, moving needed substances or waste
in and out
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Plasma membrane
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Cholesterol- positioned among
phospholipids- helps prevent fatty acid tails
from sticking together
Carbohydrates- attached to proteins, often
stick out of plasma membrane- helps cell
identify signals
Organelles within the cellEukaryotes
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Each organelle has a
unique structure and
function
Allow cell to carry out
essential processes
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Cytoplasm:
 clear fluid
 jelly-like
Nuclear Structures
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Nucleus:
control center
 contains DNA
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Nucleolus:
small dense region
 makes ribosomes
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Nuclear Membrane:
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protects the nucleus
Ribosomes
Ribosomes
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The “factories” of
cells
Involved in protein
synthesis
Endoplasmic Reticulum
Endoplasmic Reticulum
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2.
Extensive membrane system of folded sacs and
interconnected channels- large surface area for
cellular functions to take place
Continuous with outer nuclear membrane
Serves as the site for protein and lipid synthesis
Two types
Rough (ER)- has ribosomes on it that produce
proteins for export
Smooth (ER)- lacks ribosomes and is involved in
membrane lipid synthesis
Golgi apparatus
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Flattened stack of membranes
Modifies, sorts, and packages proteins into
sacs called vesicles
Vesicles can than fuse with the cell’s plasma
membrane to release proteins to the
environment outside the cell or they can be
used internally
Golgi apparatus
Mitochondria
Powerhouse of cell
 Site of aerobic respiration
Sugar+oxygen ATP+carbondioxide+water
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Lysosomes
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Lysosomes- found
only in animal cells
“Clean-up crew”
Contain enzymes for
use in the breakdown
of
worn-out organelles
Food particles
Bacteria and viruses
Centrioles
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Groups of
microtubules that
function during cell
division
Usually located near
the nucleus
Present in animal cells
and most protists
Cilia and Flagella-cell movement
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Some eukaryotic cells
have these, composed
of microtubules
Cilia- short numerous
projections that look
like hairs- oar like
motion
Flagella- longer, less
numerous-whip
motion
What about Plant cells?
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Similar in many
respects to animal
cells
Differences
Cell wall
Chloroplasts
Vacuoles-large
Cell Wall
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Thick, rigid, mesh of
cellulose fibers
Rigid cell walls allow
plants to stand at great
heights
General Sherman- largest living
thing
Chloroplasts
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Site of Photosynthesis
Converts solar energy
to chemical energyATP and sugars
Chlorophyll: green
pigment which
captures light
Vacuoles
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Membrane bound
vesicle
Used to store food,
waste products,
enzymes, and other
materials needed by the
cell
Some animal cells
contain vacuoles- they
are much smaller than
those in plants
Comparing Plant &
Animal Cells
Structure
cell
membrane
cell wall
nucleus
ribosomes
E.R.
Animal ?
Plant?
golgi
lysosomes
vacuoles
mitochondria
chloroplasts
Comparing Plant &
Animal Cells
Structure
Animal ?
Plant?
cell
membrane
cell wall
Yes
Yes
No
Yes
nucleus
Yes
Yes
ribosomes
Yes
Yes
E.R.
Yes
Yes
golgi
Yes
Yes
lysosomes
Yes
No
vacuoles
Small
Large
mitochondria
Yes
Yes
chloroplasts
No
Yes
Cellular Transport
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Moves substances within the cell and moves
substances into and out of the cell
Diffusion/osmosis
Facilitated diffusion
Active transport
Diffusion
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Random motion from
high concentration to
low
No energy required
Rate of diffusion is
affected by
Concentration
Temperature
Pressure
Osmosis
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The diffusion of water
across a selectively
permeable membrane
If cell is in a solution that
has a lower concentration
of solute/water=hypotonic
If cell is in a solution that
has a higher concentration
of solute=hypertonic
If cell is in a solution that
has an equal concentration
of solute=isotonic
Facilitated Diffusion
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Uses transport
proteins to move ions
and small molecules
across the plasma
membrane
Uses concentration
gradient for energy
Conformational
change in protein
allows passage
Active Transport
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Moves substances
against concentration
gradient
Accomplished by
protein pumps
Na+/K+ ATPase
pump is an example
Requires energy(ATP)
Transport of Large Particles
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Endocytosis- cell
surrounds a substance
with plasma
membrane- pinches it
of to form vacuole
Exocytosis- cell
releases a substance at
plasma membrane
Both processes require
energy(ATP)