Download The Cell - LaPazColegioWiki2012-2013

The Cell Structure and
Function
The Discovery of the cell

______________________
– Used a microscope to identify small pieces of cork
which he called “CELLS”

______________________
– Concludes that plants are made of cells

______________________
– Concludes that all animals are made up of cells

______________________
– All cells come from existing cells
Cell Theory
Transmission Electron
Microscope
Electron
microscopes show
details not visible
with light
microscopes.
 Uses electron
beams to focus
and magnify an
image.
 Higher
magnification

Microscopes

Light microscopes 1000x
– Produce magnified images by focusing visible
light

Electron microscopes
– Produce magnified images by focusing beams
of electrons. (can’t use living specimens)
– TEM –
– SEM –
Inside the cell
2
types of cells
–___________
–___________
You
Found on
Earth after
prokaryotes
Types of Cells (General)

Prokaryotes
– ____________________________
– “primitive cells”
– Ex. Bacteria

Eukaryotes
– Have a _____________ and usually are
bigger and have more organelles than a
prokaryotic cell does.
– Ex. Plant and animal cells
Eukaryotes
Like
Chicago
–Big city
–Lost of stuff
–Everything
you need to
live
Prokaryotes
Like
______
–Not too big
–Simple
–Small city
Eukaryotes vs. Prokaryotes
Eukaryotes
Every living
organism (except
bacteria)
 Cell membrane
 Cytoplasm
 Ribosomes (make
protein)
 PROKARYOTES

Cell membrane
 Cytoplasm
 Ribosomes
 No organelles

Nucleus
Surrounded by a double layered membrane
called the nuclear envelope.
 Contains DNA
 _________________

– Dense molecules of DNA & protein

___________________
– Chromatin stands that coil and condense.
– “blueprints” that control cellular activity.

______________________
– Site where ribosomes are built
Cytoplasm

__________________________________
__________________________________

Made up of cytosol & organelles

Organelles
– Structures that work like miniature organs,
carrying out specific functions in the cell.
Organelle Analogies

If the cell was a factory
– _______________
 The energy supply; power supply
– _______________
 Solar panels
– _______________
 The control center / boss’ office
– _______________
 Network or assembly line for proteins
– _____________
 Mail room – packaging and sorting of materials
– _____________
 The janitor
– _____________
 Specific janitor
– _____________________
 Pipes that come off the factory
– _____________________
 Security desk
– ______________
 Carpenters that build proteins
Plant Cells
Plants have a cell wall unlike animal cells
made up of a strong polysaccharide
cellulose.
 Have chloroplasts


Chromoplasts & carotanoids – other colors
Cell Shape

The shape of the cell usually depends on
its function
– Ex. Nerve cells – long & stringy
 Plants – rigid

Cytoskeleton
– Made up of microtubules & microfilaments
Microtubules

Maintain the shape of the cell & serve as
tracks for organelles to move upon
Microfilaments
Can contract
 Found in high concentration in muscle
cells

Figure 7-11 Cytoskeleton
Section 7-2
Cell membrane
Endoplasmic
reticulum
Microtubule
Microfilament
Ribosomes
Go to
Section:
Mitochondrion
Plant vs. Animal Cell
PLANT
Animal
 ___________
 No
 ___________
 Cell
membrane
 Large vacuoles
chloroplast
 ____________
 Cell membrane
 ____________
Venn Diagrams
Section 7-2
Prokaryotes
Eukaryotes
Cell membrane
Contain DNA
Animal Cells
Centrioles
Go to
Section:
Plant Cells
Cell membrane
Ribosomes
Nucleus
Endoplasmic reticulum
Golgi apparatus
Lysosomes
Vacuoles
Mitochondria
Cytoskeleton
Cell Wall
Chloroplasts
Nucleus
Endoplasmic reticulum
Golgi apparatus
Lysosomes
Vacuoles
Mitochondria
Cytoskeleton
Figure 7-5 Plant and Animal Cells
Section 7-2
Smooth endoplasmic
reticulum
Vacuole
Ribosome
(free)
Chloroplast
Ribosome
(attached)
Cell
Membrane
Nuclear
envelope
Cell wall
Nucleolus
Golgi apparatus
Nucleus
Mitochondrion
Rough endoplasmic reticulum
Plant Cell
Go to
Section:
Figure 7-5 Plant and Animal Cells
Section 7-2
Nucleolus
Nucleus
Ribosome
(attached)
Nuclear
envelope
Mitochondrion
Smooth
endoplasmic
reticulum
Rough
endoplasmic
reticulum
Centrioles
Golgi apparatus
Animal Cell
Go to
Section:
Ribosome
(free)
Cell
Membrane
Parts of the cell

Cell Membrane (plasma membrane)
– A thin layer of lipid and protein that separates
the cell’s contents from the world around it.
– Phospholipids are polar
 The two ends are opposites of each other.
Crossing the membrane

To stay alive, a cell must exchange
materials such as food & wastes with its
environment
– To do this it must pass material through the
plasma membrane

Phosphate head is
hydrophilic

Tail is hydrophobic

Cell membrane
consists of 2
phospholipid layers
called a bilayer
Figure 7-12 The Structure of the
Cell Membrane
Section 7-3
Outside
of cell
Proteins
Carbohydrate
chains
Cell
membrane
Inside
of cell
(cytoplasm)
Go to
Section:
Protein
channel
Lipid bilayer
Semipermeable membrane
__________________________________
__________________________________
__________________________________
 Small molecules, such as water, can go in
and out freely, but large molecules
cannot.
 Ions cannot pass through either

Passive Transport
Transport of substances that
__________________________________
 3 types

Diffusion

The net movement of
molecules from an
area of high
concentration to an
area of low
concentration.

Speed of diffusion
– Depends on
temperature and size
of molecule
Concentration Gradient

The difference between the concentration
of a particular molecule in an area and the
concentration in an adjacent area.

Diffusion always occurs down a
concentration gradient, from area of
greatest concentration to areas of lesser
concentration
Osmosis

The movement of
__________ through a
semipermeable
membrane from areas of
high concentration to
areas of low
concentration.

Refers to the
concentration and
movement of
___________
Hypertonic solutions

The concentration of solutes outside the
cell is greater than the concentration of
solutes inside the cell.

In hypertonic solutions,
_________________________________
Video 2
Video 2
Osmosis

Click the image to play the video
segment.
Hypotonic solutions

The concentration of
solutes outside the
cell is lower than the
concentration inside
the cell.

In hypotonic
solutions,
__________________
Isotonic solutions

The concentration of solutes inside the cell
equals the concentration of solutes
outside the cell.
Video 3
Video 3
Passive Transport

Click the image to play the video
segment.
Facilitated Diffusion

A type of passive
transport that uses
carrier proteins to
help pass large
molecules through
membrane.

EX.
Video 4
Video 4
Active Transport

Click the image to play the video
segment.
Active Transport

__________________________________
__________________________________.
Move solutes __________ the
concentration gradient
 Ex. Na/K pump

– EX. plant roots absorbing nutrients in the
soil.
Figure 7-19 Active Transport
Section 7-3
Molecule to
be carried
Energy
Molecule
being carried
Go to
Section:
Exocytosis and endocytosis –
transport of large molecules

___________________
– The cell secretes marcomolecules by the fusion of
vesicles with the plasma membrane

___________________
– The cell takes in macromolecules or substances from
the plasma membrane
– 3 types
 1. phagocytosis – “cellular eating”
 2. pinocytosis – “cellular drinking”
 3. receptor – mediated endocytosis
– Extracellular substances bind to receptors called ligands and
the substances are then brought into the cell
Video 5
Video 5
Endocytosis and Exocytosis

Click the image to play the video
segment.
Multicellular advantages
Cells throughout an organism can develop
in different ways to perform different ways
to perform different tasks
 ___________________

– Different cells with different functions
– Ex. Blood cells, nerve cells, muscle cells
Levels of Organization

_______________
– A group of similar cells that perform a particular
function
– Ex. Smooth muscle tissue

_______________
– Many groups of tissues that work together.
– Ex. Stomach

_______________
– A group of organs that work together to perform a
specific function.
– Ex. Digestive system