Download Types of Cells - Wando High School

Types of Cells
• There are two broad groups of cells
– Prokaryotes
• Do NOT have membrane-bound organelles
– Eukaryotes
• DO have membrane-bound organelles
• Organelle
– Structure within a cell that is surrounded by a
membrane and has a specific function for cell
survival
Prokaryotes
• No membrane-bound
organelles
• DNA not bound in a
nucleus
• Many prokaryotes are
unicellular
• This cell type includes all
bacteria
Eukaryotes
• Does Contain
membrane-bound
organelles
• DNA is bound in a
nucleus
• Eukaryotes may be
unicellular (algae and
yeast) or multicellular
(plants and animals)
Plasma Membrane
• Boundary of the cell
• Controls what goes in
and out of the cell
through the selectively
permeable membrane
– Keeps some things out
and lets some things in
• Maintains cell’s
homeostasis
Plasma Membrane Components–
Phospholipid Bilayer
• Two layers of phospholipids give the cell a stable yet
flexible boundary
• Makes up the majority of the plasma membrane
• Hydrophilic exteriors
– Water “loving”
• Hydrophobic interior
– Water “hating”
• Why?
– Structure of the molecule!
– Phosphate head = hydrophilic, polar
– Hydrocarbon tails = hydrophobic, non-polar
Plasma Membrane Components–
Membrane Proteins
Carrier
Marker
Channel
Receptor
Plasma Membrane Components–
Fluid Mosaic Model
• The phospholipids move freely within the
membrane (but do not flip to the other side)
– Fluid
• The membrane proteins float on and
around the membrane like little boats
– Mosaic
• These comparisons are why this
plasma membrane structure is called
the fluid mosaic model
Cell Wall
•
•
•
•
Found outside the cell membrane
Gives the cell added support and protection
Made of the carbohydrate, cellulose
This mesh of cellulose is porous and allows
anything to pass through
• Plants, fungi, and most
bacteria (prokaryotes)
have cell walls
• Animals DO NOT
Nucleus and Nuclear Envelope
• Controls most of the cell processes and contains the DNA (like
the brain of the cell)
• In almost all eukaryotic cells (plants AND animals)
• Made up of a few parts:
– Chromatin- tangled strands of
DNA bound to protein, spread
throughout nucleus becomes
visible chromosomes during
cell division)
– Nucleolus- small dense region
where assembly of the ribosome
begins
– Nuclear Envelope- double-membrane layer with pores that
allow material to move in and out of the nucleus
Mitochondria
• Transform food energy into high-energy compounds
that the cell can use to power growth, development,
and movement
• The “POWERHOUSE”
• Smooth outer membrane
and highly-folded
inner membrane
• The more energy a cell needs,
the more mitochondria
they may have
– For example, a muscle cell would need more mitochondria
than a bone cell because it requires more energy to do its job
• In eukaryotic cells
Chloroplast
• Use energy from sunlight to
make energy-rich molecules
during photosynthesis
• Have a double membrane and
the green pigment chlorophyll
• Inner membrane is folded into
disks called thylakoids that are
arranged in stacks called grana
• Only found in plants and
algae
Ribosomes
• Function: Produce proteins following coded
instructions that come from the nucleus
• Structure: Made of a large unit and a small unit
that only come together when they are making
a strand of protein
• Can be free or on the
Rough Endoplasmic
Reticulum
• In eukaryotes AND
prokaryotes
Endoplasmic Reticulum (ER)
• Structure: folded membranes
within the cytoplasm
• “Workplace” of the cell
• Rough ER Function:
– modifies the proteins that
are made on its ribosomes
• Smooth ER Function:
– Contain special enzymes and
help to make lipids for the
cell membrane.
• In eukaryotes only
Golgi Apparatus
• Structure: flattened system of
tubular membranes
• Function: Receives modified
proteins form the ER and
completes the processing of the
proteins, packages them in
vesicles, and ships them out to
their destinations within or out of
the cell. Also organizes
lysosomes.
• In eukaryotes
Lysosomes
• Small organelles
containing digestive
enzymes to break down
food particles, worn out
organelles, bacteria, and
viruses into particles that
can be used by the rest of
the cell
• The “Wrecking Crew”
of a cell
• In eukaryotes
Vacuoles
• Sac-like structures that store materials such as
water, salts, proteins, and carbohydrates
• Plants have one large vacuole that also helps
give support to flowers and leaves
• In eukaryotes
animal
plant
Centrioles
• Structure: Look like a pair of hollow
cylinders which lie perpendicular to each
other near the nucleus of the cell.
• Function: Plays a role in organizing the
mitotic spindle during cell division; plays
a role in organizing the basal bodies
that build cilia and flagella.
• Only in Animal Cells
Cilia and Flagella
• Function: Helps to move the cell or its outer
environment; some organisms use them to
capture food.
• Cilia – short, numerous, hair-like projections
that move in a wavelike motion
• Flagella – longer projections that move in a
whip-like motion
• Major means of
locomotion for
unicellular organisms
Cytoskeleton
• A network of protein filaments that helps the
cell maintain its shape and helps with cell
movement
– Microtubules- hollow tubes
of protein that maintain cell
shape
– Microfilaments- long, thin
fibers that function in
movement and support of
cell. Smaller than
microtubules
Prokaryotes vs. Plants vs. Animals
Eukaryotes
Plants
Animals
Organelle
Prokaryotes
Plasma
Membrane
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Cell Wall
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Nucleus
DNA
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Mitochondria
Chloroplasts
Ribosomes
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Prokaryotes vs. Plants vs. Animals
Organelle
Prokaryotes
Endoplasmic
Reticulum
Golgi
Apparatus
Eukaryotes
Plants
Animals
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Lysosomes
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Vacuoles
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Centrioles
Cilia or Flagella
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Cell Size
• Cells will grow larger to a certain point and then
their growth will slow down
• Eventually they will stop growing and divide
into two smaller cells
• These smaller cells will then grow until they
divide
• Why not just keep growing?
Surface Area vs. Volume
• Materials must move through the cell by diffusion or
by vacuole transport
• The further materials travel, the more time and/or
energy must be used to move them
• Larger cell means a greater surface area for exchanging
materials BUT also means a larger volume through
which materials must travel
• Cells must maintain the proper
surface area/volume ratio
• Membranes in the cell are often folded
to create greater surface area for exchange
– Example - Mitochondria