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Cell Structure
and Function
7.1 Life is Cellular
Objective
Explain what
the cell
theory is.
Robert Hooke 1665
ANTON VAN LEEUWENHOEK – made his own
lenses made first compound microscope drew
pictures that we can still identify today.
Schleiden –concluded all plants
are made of cells
Schwann – concluded all
living things are made up of
cells
Lynn Margulls
Proposes the
idea that certain
organelles, tiny
structures within
some cells, were
once free- living
cells themselves.
CELL THEORY
1. ALL LIVING THINGS
ARE COMPOSED OF
CELLS
2. CELLS ARE THE BASIC
UNIT OF STRUCTURE
AND FUNCTION IN
LIVING THINGS
3.ALL CELLS ARE
PRODUCED FROM
OTHER CELLS
Prokaryote
Cells that do not contain nuclei.
Cells that have genetic material
that is not contained in a
nucleus.
Examples of prokaryotes
Eukaryotes
Cells that contain nuclei.
Contains a nucleus in which
their genetic material is
separated from the rest of the
cell.
Examples of
Eukaryotes
Gather your thoughts
 What is the main difference between
prokaryotic cells and eukaryotic cells?
 Do bacterial cells conatin a nucleus?
 What else do eukaryotic cells contain
that prokaryotic cells don´t?
Construct a Chart
Trait
Prokaryotes
Nucleus
Organelles
Cell Membranes
Organisms
www.phschool.com code: cbd-3072
Eukaryotes
7-2 Eukaryotic Cell Structure
Objectives:
•Describe the
function of the cell
nucleus.
•Describe the
function of the major
cell organelles.
•Identify the main
roles of the
cytoskeleton.
Organelles – Structures that act as specialized
organs. Also called “little organs”.
Cytoplasm – The portion of the cell outside the
nucleus.
Nucleus
 Contains nearly all the cell`s DNA and with it the
coded instructions for making proteins and other
important molecules.
Nucleus
Chromatin
DNA bound to
protein.
Chromosomes
Structures contain
the genetic
information.
Nucleolus
Where the
assembly of
ribosomes begin.
Nucleus
Nuclear Envelope – It surrounds the nucleus and is
composed of two membranes.
It is dotted with nuclear pores, which allows material to
move into and out of the nucleus:
 Messages
 Instructions
 Blueprints moving in and out.
Gather your thoughts
What is the nucleulus?
Where is the DNA that a nucleus
contains?
Why is DNA important?
Ribosomes
Are small particles of RNA and
proteins found throughout the
cytoplasm.
Proteins are assembled on
ribosomes.
They produce proteins by following
coded instructions that come from
the nucleus.
Endoplasmic Reticulum
 Ths site where lipid components of the cell membrane
are assembled, along with proteins and other materials
that are exported from the cell.
Rough
It is called rough ER because
of the ribosomes found in
the surface. Newly made
proteins have leave thses
ribosomes and are inserted
into the rough ER.
Smoth
Has no ribosomes and makes
lipids and help in
detoxification.
Endoplasmic
Reticulum
Gather your thoughts
 What are ribosomes composed of?
 What do ribosomes produce?
 What happens to these proteins after
they´re produced by ribosomes?
 If this were an illustration of smooth ER,
how would it be different?
 What is the function of smooth ER?
Golgi Apparatus
 To modify, sort, and package proteins and other
materials from the endoplasmic reticulum for storage
in the cell or secretion outside the cell.
ER- Golgi conection
Lysosomes
 Small organelles filled with enzymes.
 Function: Digestion of lipids, carbohydrates and
proteins into small molecules.
Vacuoles
 Store
materials
such as water,
salt, proteins
and
carbohydrate
s.
Gather your thoughts
How is the function of a
vacuole in a plant cell different
from that in a unicellular
organism?
Mitochondria
 Organelles that convert the chemical energy stored in
food into compounds that are more convenient for the
cell to use.
Chloroplasts
 Organelles
that capture
the energy
from sunlight
and convert it
into chemical
energy in a
process called
photosynthes
is.
Organelle DNA
 Chloroplasts and mitochondria contain
their own genetic information in the form of
small DNA molecules.
 Lynn Maegulis, suggested that
mitochondrias and chloroplasts are
descendant of ancient prokaryotes.
Cytoskeleton
 A network of protein filaments that help the cell to
mantain its shape. The cytoskeleton is also involves in
movement.
Centrioles
 Important in cell division, which helps to separate
chromosomes.
 They are in the nucleus and help organize cell
division.
 They are not found in plant cells.
Gather your thoughts
How is a house frame like a
cell´s cytoskeleton?
7-3 Cell Boundaries
Cell Membrane
The cell membrane
regulates what enters
and leaves the cell
and also provides
protection and
support.
The composition of
nearly all cell
membranes is a
double- layered
sheet calles a lipid
bilayer.
 The cell membrane regulates what enters and leaves
the cell and also provides protection and suport.
Lipid Bilayer- A membrane with a doble- layer
Cell Walls
 The main function of the cell wall is to
provide support and protection of the
cell.
Cytoplasm – Contains a solution of many different
substances in water.
Solution- A mixture of two or more substances.
Solute – Substances dissolved in the solution.
Concentration – A solution is the
mass of solute in a given volume
of solution.
Mass/ Volume
12 Grams of salt
12 Grams of Salt
3 Lt. Water
6 Lt. of Water
What solution has the most
concentration?
Concentration
12 g./ 3 L. or 4 g/L
12 g./6L or 2g/L
The first solution is twice as concentrated
as the second solution.
More concentration
If you dissolved 12 grams of
salt in 3 liters of water, what
is the concentration for salt
in the solution?
Suppose you added 12
more grams of salt to
the solution. What
would be the resulting
concentration?
What if you then
added another 3
liters of water to
that solution
concentration?
Which solution of
the ones discussed
would be called
the most
concentrated?
Diffusion
 Particles move constantly. The
particles tend to move from an area
where they are more concentrated to
an area where they are less
concentrated.
Equilibrium- when the concentration of the solute is
the same throughout a system.
Diffusion depends upon random particle
movemnts, substances diffuse across
membranes without requiring the cell to use
energy.
Osmosis
Is the diffusion of water through a
selectively permeable membrane.
Permeable
Some substances can pass across then and others
cannot.
Isotonic- The concentration of solutes is
the same inside and outside. “Same
Strength”
Hypertonic – Solution has a higher solute
concentration than the cell. “Above
Strength”
Hypotonic – Solution has a lower solute
concentration than the cell. “Below
Strength”
Watch this for a better
explanation on hypertonic
and
hypotonic
http://www.youtube.com/watch?v=DpVbcJY4amA
http://www.youtube.com/watch?v=1vQzqk2hzj8&featur
e=related
Gather your thoughts
In the beaker on the left, which
solution is hypertonic and
which is hypotonic? Pg. 185
In this model, to which
material is the membrane
permeable, water or sugar?
Visual Activity
www.phschool.com
Code: cbp-3075
Osmotic pressure
For organisms to survive, they must have a way to
balance the intake ans loss of water.
Cells in large organisms are not in danger of bursting.
Plant cells and bacteria are surrounded by tough cel
walls. The cell walls prevent the cells from expanding
even under tremendous osmotic pressure.
Facilitated Diffusion
Cell membranes have protein channels that make it easy
for certain molecules to cross the membrane.
Cell membrane protein facilitate the diffusion of
glucose, or other substances across the membrane.
The net movement of molecules across a cell membrane
will occur only if there is a higher concentration of the
particular molecules on one side than on the other
side.
No energy is required.
Active Transport
Sometimes it must move materials in the opposite
direction, against concentracion difference.
It requires energy.
It can be by transport proteins or “pumps” that are found
in the membrane.
Larger molecules can be processes by endocytosis and
exocytosis.
Endocytosis
The process of taking material into the cell by means of
infolding of the cell membrane.
The poket that results breaks loose from the outer
portion of the cell membrane and forms a vauole
Phagocytosis
The cell engulfs
particle and
package it within
a food vacuole.
Pinocytosis
Cells take
up liquid
form the
surrounding
enviroment
by
introducing
valuoles of
water.
The release of large amounts of material from
the cell. The membrane of the vacuole
surrounding the material fuses with the cell
membrane forcing the contents out of the cell.
Phagocytosis
Endocytosis
(Particles, food
vacuole)
Pinocitosis
Exocytosiscytosis
Active
Transport
(Release large
amount of
material
Molecular
Transport
(Liquid vacuoles)
Proteins in the
membrane
change in shape
to make them
come trough.
Energy is
required.
Quick Lab
 How can you model permeability in cells?
Materials: graduated cylinder, plastic sandwich
bag, starch, twist tie, 500 ml beaker, iodine
solution
Procedure:
1- Pour about 50 ml of water into a plastic
sandwich bag. Add 10 ml of starch. Secure the
2- Put on your goggles, plastic gloves and
apron.
3- Pour 250 ml of water into a 500 mL
beaker.
4- Place the sandwich bag of water and
starch into the beaker of water and
iodine.
5- After 20 minutes, look at the sandwich
bag in the beaker. Observe and record any
changes that occurred.
http://staff.tuhsd.k12.az.us/gfoster/standard/bcell1.htm
http://io.uwinnipeg.ca/~simmons/cm1503/membranefunction.htm