What is this
The Compound Light Microscope

can produce magnifications of 50X to 500X
Electron Microscope
Uses a beam of
electrons
 Magnifying powers in
excess of 100,000X
 Specimens must be
dead or non-living

Robert Hooke (1665)
British scientist
 used a microscope to study
a thin slice of cork from the
bark of an oak tree
 named the box-like
structures “cells”
 saw only dead cells

Anton van Leeuwenhoek
(1600s)

Dutch businessman; his single-lens
microscope magnified objects 200X and
allowed him to see tiny organisms in a
drop of water (animalcules)
Robert Brown (1831)

Scottish botanist; used newly developed
stains; first to describe the cell nucleus
Matthias Schleiden (1838)

German botanist; concluded that all
plants are made up of cells
Theodor Schwann (1839)

German scientist; concluded that all animals
are made up of cells
Rudolf Virchow (1855)
German physician; studied cell
reproduction
 “Where a cell exists, there must have
been a preexisting cell…”

Cell Theory

Cell Theory Song
Cell Theory
1. All living things are made up of cells
2. Cells are the basic units of structure and
function in living things
3. All cells arise from preexisting cells
The Cell
The Cell
Intro Video
Two Main Types of Cells
Eukaryotic cells
Found in plants, fungi, animals and Protists
1. Have a true nucleus containing chromosomes
2. Contain several membrane bound
organelles
3. Cells are 10-100 um in length
(1 mm = 1,000 um)
Two Main Types of Cells
Prokaryotic cells
- Ex: Bacteria
- 1/10th the size of eukaryotic cells
- No nucleus
- Cell Wall – (Peptidoglycan)
Prokaryotic cell
Why are Cells Small
The Volume of a cell determines
the amount of metabolic activity it
carries out
The Surface Area of the cell
determines the amount of
substances that are carried into the
cell and the amount of waste
removed from the cell
Why are Cells Small
As a cell gets bigger the volume increases
compared to the surface area. At some point the
cell won’t be able to function
Parts of the Eukaryotic Cell
Nucleus
Nuclear Membrane/
Nuclear Pore
Chromatin
Nucleolus
Riibosomes
Rough Endoplasmic
Reticulum
Cell
Membrane
Lysosome
Smooth
Endoplasmic Reticulum
Centrioles
Mitochondria
Golgi Body
Cell Organelles
“little organs”
 specialized parts of the cell which carry
out specific life functions

Inside the Cell
1. Plasma Membrane
( Cell Membrane )
separates cell from surrounding environment
 controls the movement of molecules into or
out of the cell
 selectively permeable (semi-permeable)
 visible with the compound microscope

The Cell Membrane Structure
Fluid Mosaic Model
Phospholipid Bilayer
Made up of two layers of phospholipids

Flexible structure with freely moving
pieces

Composed mainly of lipids and proteins
phospholipid
Phospholipid bilayer

Polar heads: hydrophilic
(water-loving); in contact with
cytoplasm/extracellular fluid

Non-polar tails: hydrophobic
(water-hating); interior of membrane
Phospholipid Bilayer
Fluid Mosaic Model of Membrane Structure

Integral proteins: are proteins extend
through the membrane or are found on the
outer/inner surface (transport proteins)
Fluid Mosaic Model of Membrane Structure
Peripheral Proteins are on the outer/inner
surface of membrane
They act as receptors and they attract
substances to cell membrane and aide in
communication with other cells.
Fluid Mosaic Model of Membrane Structure
Carbohydrates are on the outer surface
for cell communication
Cholesterol is imbedded in the bilayer to
give the membrane additional support
Cell Membrane
Fluid Mosaic Model of Membrane Structure

fluid mosaic model animation
2. Cytoplasm




watery material within the cell
membrane
suspends organelles
site of chemical reactions
supported by a cytoskeleton: fibers that
controls movement of cell or of its
internal parts
3. Nucleus
contains DNA on structures
called chromosomes
 surrounded by a nuclear
membrane that has pores
(selectively permeable)
 visible under the compound
light microscope

Nucleus
4. Nucleolus
located within the nucleus
 site of ribosome synthesis

In notebook: Sketch and label the Nucleus, Cytoplasm and
Cell Membrane of these three cells
_____________________________________________________________________
Red Blood Cells
Cheek Cell
Brain Cell
5. Ribosomes
site of protein synthesis
 some ribosomes are found in the
cytoplasm
 other ribosomes are attached to the
outside of an organelle called the
endoplasmic reticulum (ER)

The Endomembrane System
Includes the:
1. Endoplasmic reticulum
2. Golgi apparatus
3. Lysosomes
4.Vacuoles

6. Endoplasmic Reticulum
network of channels for carrying
substances from one part of the cell to
another
 usually found near the nucleus

There are two types of endoplasmic reticulum (ER)

Rough ER is
dotted with
ribosomes
There are two types of endoplasmic
reticulum (ER)

smooth ER
lacks ribosomes
 involved in synthesis of
lipids


metabolism of
carbohydrates

detoxification of drugs and
other poisons
7. Golgi apparatus
8. Golgi apparatus
stacks of membranes forming flattened sacs
 process, package, store cell products to be
secreted (transported out of the cell)

Ribosomes ►RER ►SER ►Golgi ► Vacuole ► cell membrane ►release from cell
Golgi apparatus animation
Endomembrane system animation
Exocytosis – release of a substance outside of the cell
membrane by the fusion of a vacuole
9. Lysosomes

sac of digestive enzymes

digest organic molecules,
worn-out cell structures,
harmful bacteria
10. Vacuoles
 variety
of functions:
1) food vacuoles
2) contractile vacuoles in
freshwater protists pump out excess
water (In action)
3) plant cells have a large central
vacuole for water and nutrient storage
4) Vesicle – A tiny vacuole
11. Mitochondria





“powerhouse of the cell”
site of cellular aerobic respiration: glucose +
oxygen is converted to energy in the form of
ATP
each cell contains between 300-800
mitochondria depending on activity level
has a double membrane
inner membrane has many foldings = cristae
Mitochondria

although most of a cell's
DNA is contained in the
cell nucleus, mitochondria
also have their own DNA
(maternal)
Endosymbiotic Theory
mitochondria are descended from
independent prokaryotes that were
engulfed by other cells but not digested
 the mitochondria gave the cell that
engulfed it a selective advantage over
other cells

Endosymbiotic Theory
12. Centrioles/Centrosome
small bundle of microtubules
 found in pairs near cell
nucleus
 A pair is called is called a
Centrosome
 involved in cell division
 found in animal cells but not
plant cells

Plant Cells
DO NOT have Centrioles
 Have Chloroplasts
 Have Cell Wall – Cellulose
 Have Large Central Vacuole

13. Plastids
Found ONLY in plants and algae
 Double Membrane
 Three types:
1. Chloroplast – Green and site of
Photosynthesis (See Next two slides)
2. Leucoplast – Colorless and store starch –
mainly found in roots
3. Chromoplast – Carotenoid pigments:
Responsible for red color in carrots and other
plants

Chloroplasts

contain
chlorophyll, a
green pigment
that absorbs
light to start
photosynthesis
Chloroplasts
Chloroplasts
contain their own DNA
 chloroplasts are also part of the
endosymbiotic theory

14. Cell Wall
found in plant cells only
 made of cellulose
 provides protection &
structure for the cell;
prevents expansion

15. Cytoskeleton
a network of fibers extending throughout
the cytoplasm
 is made up of microtubules and
microfilaments


functions:
mechanical support, maintains shape,
allows for movement

Microfilaments are made up of a
protein called actin.

They help support the shape of the cell
and movement of the cell

The cytoskeleton can
change the shape of a
cell
– This allows cells
like amoebae to
move
Video
Figure 4.19B

Microtubules are thick hollow tubes of
protein that make up Cilia, Flagella and
Spindle Fibers
Cilia and Flagella
Cilia and Flagella are motile appendages that
help the cell move


Flagella propel the
cell in a whip like
motion
• Cilia move in a
coordinated back-andforth motion
Figure 4.20A, B
Spindle Fibers
Centrioles lie near the nucleus
 Help produce Spindle Fibers that help in
cell division

Microtubule Arrangement

Centrioles and Spindle Fibers: ( 9 Triplets)
Consists in 9 Triplets of microtubules
arranged in a circle
Microtubule Arrangement

Cilia and Flagella: ( 9 + 2 )
Consists in 9 Pairs of microtubules around
2 single microtubule
Electron Micrograph of the
Cytoskeleton