Download Cells

Cells were invisible to the naked eye until
microscopes were invented in the 1600’s.

Robert Hooke (1665)


Anton van Leeuwenhoek (1674)


First to identify and name cells
First to describe living cells by looking at pond water
Schleiden & Schwann (1838-1839)

First to note that both plants and animals are made of cells
The lens through
which you look into
a microscope
Part by which the microscope is carried
The movable surface on which slides are placed
Used for general focusing of microscope
Used for fine detailed
focusing of a
microscope
Part on which the
microscope rests. Also
held when carrying the
microscope from place
to place.
Source of light found near the base of the
microscope. The light source makes the
specimen easier to view.
Controls the amount of
light that enters through
the stage
Holds the slides in place
Composed of a low power, medium power,
high power, and oil immersion lens. Used to
view specimens at different magnifications.
Revolving circular structure containing
objective lenses.
 All
living things are made of one or more cells
 Cells
are the basic units of structure and
function in all organisms
 All
cells come from preexisting cells

“Pro” = before
 Contains
“Karyote” = nucleus
no nucleus
 DNA is found in the cytoplasm
 Contains no membrane bound organelles
 All are single celled

“Eu” = true
 Contains
“Karyote” = nucleus
a nucleus where DNA is found
 Contains membrane bound organelles
 May be single celled or multicellular
• Cell Membrane
• Golgi Apparatus
• Cytoplasm
• Vesicle
• Cell Nucleus & Nucleolus
• Vacuole
• Ribosome
• Mitochondria
• Endoplasmic Reticulum
Plant Cell
•
Animal Cell

Structure
 2 rows of lipids and protein molecules

Location
 Outside perimeter of cell

Function
 Regulates movement of substances in and out of the
cell

Structure
 Jelly-like matrix interior containing molecular building
blocks

Location
 Enclosed inside the cell membrane in which all
organelles are found

Function
 Maintains the shape of the cell and “provides a home”
for all organelles

Structure

Nucleus: Membrane bound organelle containing pores. Also carries genetic
information known as DNA.


Nucleolus: Non-membrane bound structure
Location

Nucleus: Found within the cytoplasm

Nucleolus: Found within the nucleus
** Only found in Eukaryotic Cells**

Function

Nucleus: Protects the DNA “blueprint codes” and regulates cellular activities

Nucleolus: Responsible for ultimately producing ribosomes
INTERESTING FACT!
If the nucleus were the size of a
penny then the rest of the cell
would be the size of a football field!

Structure
 Composed of a large and small subunits made of proteins
and nucleic acids

Location
 Found loose in the cytoplasm or attached to the Rough
Endoplasmic Reticulum (RER)

Function
 Make proteins from all amino acids once attached to RER

Structure
 Rough ER: twisted, flattened tube network studded by
ribosomes
 Smooth ER: branching, rounded tube network not studded
with ribosomes

Location
 Rough ER: at or around the nucleus
 Smooth ER: towards the outside of the rough ER

Function
 Rough ER: site of protein synthesis
 Smooth ER: detoxifies harmful substances and produces lipids

Structure
 Series of flattened, slightly curved membrane sacs

Location
 Near the nucleus and ER

Function
 “Shipping Center”. Packages and sorts proteins and lipids
into vesicles for transport in and out of the cell.

Structure
 Small, membrane bound sacs

Location
 Anywhere, but usually near the golgi body

Function
 Temporary storage of cell material for transport in and
out of the cell

Structure
 Fluid filled sac

Location
 In animal cells: small size & random placement
 In plant cells: one LARGE central vacuole

Function
 In plant & animal cells: temporary storage of food,
water, minerals, and wastes
 In plant cells only: serves as structural support for the
cell

Structure
 Kidney bean shaped with two membranes.
 Outer membrane is smooth
 Inner membrane that is made up of curves and folds
**Contains its own DNA codes inside that are maternal**

Location
 Randomly located inside of cytoplasm

Function
 Provides energy for the cell. Usually referred to as the
“Power House”.
 Inner membrane (cristae) converts glucose into ATP
 Lysosomes
 Centrioles
Animal Cell

Structure
 Membrane bound organelles that contain enzymes

Location
 Randomly located throughout the cytoplasm
Function
 Contains enzymes that destroy foreign particles in
the cell
 Digests worn-out organelles, food molecules, viruses,
and bacteria
 Cells “Garbage Disposal System”


Structure
 Cylinder shaped organelles, made of microtubules
arranged in a circle

Location
 Found near the nucleus, but only seen when cell is
undergoing division
Function
 Aids in cell division

 Cell Wall
 Chloroplast

Structure
 Thick layers of cellulose fibers which form a rigid
shape

Location
 Outside the cell membrane
Function
 Helps give the cell shape, support, protection, AND
connects them to neighboring cells


Structure
 Highly compartmentalized. Composed of an outer and
inner membrane & disc shaped sacs
** Contains its own DNA codes within plants **

Location
 Random in cytoplasm but usually closer to cell
membrane
Function
 Responsible for photosynthesis
 Converts light energy to chemical energy
 Contains chlorophyll which is responsible for plant
pigment


Made of a phospholipid bilayer: two parallel rows of
phospholipids
• The heads face outward
• The tails face inward

Polar head is “Hydrophyllic” = “Water loving”

Fatty Acid Tail is “Hydrophobic” = “Water fearing”

Definition:
 Allows some substances to pass across the cell
membrane, but not all.

Our cell membranes are selectively permeable

Definition:

The mass of a solute in a given amount of solution, or
mass/volume. (Example: 12 g of sugar per 3 L of
water = 4g/L concentration)

Example:

Which picture below has the greatest concentration of red dye?

Definition:


The movement of gas or liquid molecules across a
membrane from high to low concentration.
How diffusion works:

Lipids diffuse easily across the membrane (like
dissolves like)

Small particles with NO charge like O2, CO2, and H2O
diffuse easily across the membrane

Process continues until an equilibrium is achieved
[inside cell] = [outside cell]
 Definition:

The diffusion of WATER across a selectively
permeable membrane
 Water
flow across a cell membrane depends
on the solute concentration of the
surrounding liquid
1) H20 moves from:
high water concentration
low water concentration
2) “Salt Sucks”:
H O is attracted toward the high concentration of solutes
2
1) Isotonic Solution
2) Hypotonic Solution
3) Hypertonic Solution
 Refers
to two solutions having the same
concentration.


A cell in an isotonic solution will have the
same amount of water going in and
coming out.
No net gain or loss of water.

Refers to a less concentrated solutions

Hypotonic solutions have less solute and
more water.
 Therefore
cells bathed in hypotonic
solutions gain water and increase in size.


Refers to a more concentrated solution.
Hypertonic solutions have more solute
and less water.
 Therefore
cells bathed in hypertonic
solutions lose water and shrink in size.
Why could drinking too much sea
water be dangerous?
Based on the basic principles of diffusion and
osmosis!
As the salt water solution enters your body,
the cells near the solution release water in
order to reach equilibrium with the
surrounding fluid. The cells then shrink and
may die out. This is a condition called
dehydration!
 Which
cell is in a Hypertonic solution?
 Which cell is in an Isotonic solution?
 Molecules
can freely move across the cell
membrane at any time from High to Low
concentration
 Moves
by concentration gradient = NO ATP
needed
 Molecules
are “FORCED” across the cell
membrane from Low to High concentration
 AGAINST
the concentration gradient = ATP
energy needed
 The
diffusion of molecules across the cell
membrane using the help of transport
proteins
 Process
of taking liquids or fairly large
molecules into a cell by engulfing them in a
membrane (comes from a piece of the cell
membrane)
 Release
of substances out of a cell by the
fusion of a vesicle with the cell membrane