Transcript the cell - msfoltzbio

Bellwork
• What are the three main statements in the cell
theory?
• Who was the first to discover the “cell”?
• Compare the Scanning Electron Microscope,
Transmission Electron Microscope, and
Scanning Tunneling microscope by illustrating
the differences in images they capture.
Today!
• Standard B-2: The student will demonstrate an
understanding of the structure and function of
cells and their organelles.
• Objectives: I will be able to understand the
functions of different cellular structures, along
with illustrate each structure as it appears in the
cell.
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
Eukaryotes
• Does have a membrane
bound nucleus
– DNA is bound within the
nucleus
• Does Contain membranebound organelles
• Eukaryotes may be
unicellular (algae and
yeast) or multicellular
(plants and animals)
Plasma Membrane (or Cell 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
Cell Wall
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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, some protists
and most bacteria (prokaryotes)
have cell walls
• Animals DO NOT
Cell Wall
Cytoplasm
• Cytoplasm is a semifluid material inside the
cell
• It contains the
molecules and
organelles in the cell
• It is bound by the cell
membrane
Nucleus and Nuclear Envelope
• Functions in the genetic control
of the cell
• Contains the chromosomes which
are composed of DNA
• The nuclear envelope is a
membrane that
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– surrounds the nucleus
– Regulates the materials that pass
between the nucleus and the
cytoplasm
• In eukaryotic cells (plants AND
animals)
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* Important parts to know
Mitochondria
• This is the site of cellular
respiration, a process that provides
the cell with energy
• The “POWERHOUSE”
• 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
• Contains the green pigment
chlorophyll
• Chlorophyll absorbs energy
from sunlight to convert
carbon dioxide and water
into sugar during
photosynthesis
• Only found in plants and
some algae
Ribosomes
• Ribosomes are the site of
protein synthesis
• Can be found
– floating free in the
cytoplasm
– or on the
Rough Endoplasmic
Reticulum
• In eukaryotes AND
prokaryotes
Endoplasmic Reticulum (ER)
• ER is a complex, extensive
network that transports
materials throughout the
inside of the cell
• Rough ER:
– Has ribosomes attached
• Smooth ER:
– Has no ribosomes
• In eukaryotes only
Golgi Apparatus
• Function: Modifies,
collects, packages,
and distributes
molecules within the
cell or outside the
cell
• 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
• 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
• Animal cell vacuoles are much smaller than plant cell
vacuoles
• In eukaryotes
animal
plant
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
– Animal cells and protists
• Flagella – longer projections
that move in a whip-like motion
– Animal cells, bacteria, and protists
Prokaryotes
• No true nucleus
– DNA is not bound in a nucleus or
arranged in chromosomes
*
• Do not have most membranebound organelles
– They do have ribosomes for protein
synthesis
– They do not have mitochondria.
They get their energy from the sun
or from chemicals in the
environment
• Many prokaryotes are unicellular
• This cell type includes all bacteria
* Cytoplasm
* Important parts to know
*
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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
Eukaryotes
Plants
Animals
Endoplasmic
Reticulum
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Golgi
Apparatus
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Lysosomes
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Vacuoles
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Cytoplasm
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Cilia or Flagella
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