Download Nucleus

2.2
Cell Types
• With more advanced
microscopes, scientists
discovered that all cells can be
grouped into two types:
• prokaryotic cells
• eukaryotic cells
Prokaryotes: NO NUCLEUS!
• 1st cells
to evolve
• No Nucleus!
• The hereditary information
(circular DNA) is contained
within the cytoplasm.
• Examples: Archae and
Bacteria
The genetic material in a prokaryotic cell is NOT
surrounded by a membrane bound nucleus.
Eukaryotes
• Evolved from
prokaryotes
• Organisms whose cells have a nucleus.
• Hereditary information (Linear DNA) is contained within
the nucleus
• Examples:
– Animals
– Plants
– Protists
– Fungi
– “You” have Eukaryotic cells.
Unicellular Organisms (cont.)
• A cell without a
membrane-bound
nucleus is a
prokaryotic cell.
• A eukaryotic cell has a
membrane-bound
nucleus and many
other specialized
organelles.
Can you identify the two organelles that are only found in the
plant cell?
-Surrounds all cells
– In a plant cell, it lies beneath the cell wall
• It’s like the
border of a
city!
– In animal cells, it is the outer boundary (made of cholesterol)
– Serves as a gateway which helps to control materials going in and out of the
cell
• Found in both plant and animal cells
• Centrally located in cell
•The nucleus acts as the “brain” of the
cell, controls all the activities of the cell
and contains genetic information stored
in DNA.
• It’s like the Mayor’s
Office in City Hall!
Nucleus (cont.)
EM Research Services, Newcastle University
In most cells, the nucleus is the largest
organelle.
Nucleus (cont.)
• DNA in the nucleus is organized into
structures called chromosomes.
• The nucleolus is also contained in the
nucleus and makes ribosomes, organelles
involved in the production
of proteins.
• The nuclear envelope is a two-membrane
structure that surrounds the nucleus.
• Found in both plant and
animal cells
• Network of tubes that transports
materials throughout the cell
• Two types
– Smooth (no ribosomes)
– Rough (covered with
ribosomes)
It’s like a city’s
subway!
• Found in both plant and animal cells
• Can be attached to the ER Membrane or
floating free in the cytoplasm
• The smallest organelles
•Function: Synthesis- Produce proteins
and pass them to the interior of the ER.
• It’s like the brick
yard that supplies a
city with bricks!
• Found in both plant and animal cells
It’s like
a city’s
power
plant!
• Powerhouse of the cell
• Breaks down sugar molecules to release energy
• Function: Respiration- Releasing energy stored in food
food is “burned” (combined with oxygen) to produce energy for
the cell in the form of ATP
• Fluid-filled sacs found in both plant and
animal cells
– In plant cells: very few and very large
– In animal cells: many little ones
• Store food, water and waste
It’s like a city’s
warehouses,
water towers
and landfills!
• Only found surrounding plant, fungal
and bacterial cells
• A cell wall is a stiff structure outside
the cell membrane that protects a cell
from attack by viruses and other
harmful organisms.
• Made of cellulose- a tough, yet flexible
material
• Provides support, structure, and
protection for the cell
•It’s like the wall
that surrounds a
medieval city!
http://www.youtube.com/watch?v=PFtzs_cUddI
• Found in plant cells only
• Green in color due to a pigment
called chlorophyll
•They capture energy from the sun
and use it to produce food (sugar) for
the cell during photosynthesis
It’s like the solar
panels on a city’s
buildings!
• Found in both plant and
animal cells
• Coiled structures of DNA
& protein; found in the
nucleus
•City planning
office that works
with the
Mayor’s office
• Makes Ribosomes
• Found in both plant and animal cells
• It’s like a Factory!
Lysosomes
• Found in both plant and animal
cells
• Function: contains digestive
enzymes that digests old cell
parts.
• They are the cell’s clean-up
crew. They have their own
membrane to protect the cell
from their chemicals.
It’s like a city’s street
sweeper!
Golgi Apparatus
• Found in both plant and
animal cells
• Looks like a flattened stack of
membranes (or pancakes!)
• They receive proteins from
the ER and package them into
vesicles .
• Vesicles are organelles that
transport substances from
one area of a cell to another
area of a cell.
• It’s like a city’s
Post Office!
Cytoplasm
• Surrounds and protects
cell organelles
• Found in both plant and
animal cells
• Clear, thick, jelly-like
material
• Located beneath cell
• It’s like the air in a city!
membrane
• Also contains the cell’s
cytoskeleton- a network
of threadlike proteins that
give a cell its shape
Plant Cell
Animal Cell
Golgi bodies
or ER
Mitochondria
ribosomes
chloroplasts
Lysosomes
vacuoles
nucleus
Cell wall or
cell
membrane