Transcript Cell Structure & Function

Cell Structure
& Function
(What do cells look like?)
(What do cells do?)
2 main types of cells
 Prokaryotes (Prokaryotic)
 Eukaryotes (Eukaryotic)
Prokaryotes




Simple cells
Unicellular only
Typical size 1-2 μm in diameter
No nuclear membrane or other membranebound organelles
 DNA is in a tangled loop
 Some prokaryotes have a second loop of DNA
called a plasmid
 Cell walls vary but can be very “tough” to help
the cell survive harsh environments
Prokaryotic cell:
Eukaryotes
 Complex cells
 Both unicellular & multicellular organisms. (All
multicellular organisms are this type.)
 Typically about 10x larger than prokaryotic cells
 Many organelles – some common, some only in plant
cells, some only in animal cells
 DNA is extremely long so the cell condenses it to form
chromosomes
 Some eukaryotic cells differentiate. This means they
can become different types of cells: skin cells, muscle
cells, blood cells, fat cells, etc. Plants have different
types of cells too.
Eukaryotic cell:
Comparing prokaryotes to
eukaryotes
Prokaryotic cell
Simple or Complex?
Size of Cell?
Unicellular, Multicellular,
or Both
Any membrane-bound
organelles?
What does the DNA look
like?
Eukaryotic cell
Comparing prokaryotes to
eukaryotes
Prokaryotic cell
Eukaryotic cell
Simple
Complex
1 – 2 μm
Typically 10x larger
Unicellular,
Multicellular, or Both
Unicellular
Both
Any membrane-bound
organelles?
No
Yes
Tangled loop
Chromosomes
Simple or Complex?
Size of Cell?
What does the DNA look
like?
Organelles
 Little “organs” inside cells.
 Only found in eukaryotic cells.
 Each type of organelle has its own
purpose/function for the cell.
 Organelles may have once been
prokaryotic cells that were engulfed and
then incorporated into a larger cell
instead of being broken down as food.
Nucleus
 Holds genetic material
http://www2.plymouth.ac.uk/electronmicroscopy/TEM_BIOL/slides/Nucleus.jpg
November 2007
Nuclear membrane
 Selects what can enter and leave the
nucleus
Nucleolus
 An area in the nucleus that makes
ribosomes
Nuclear pore
 Controls what molecules can enter/leave
the nucleus
http://www.abdn.ac.uk/emunit/emunit/temcells/images/nuclear%20po
re%20%20.jpg
Cell wall
 Supports and protects the cell.
Root cell: http://www.abdn.ac.uk/emunit/emunit/templant/images/root%20cell%20%20.jpg
Cell membrane
 Selects what can enter and leave the
cell.
Cytoplasm
 Includes the internal part of the cell
except the nucleus.
http://www.lifesci.sussex.ac.uk/home/Julian_Thorpe/tem2.jpg
http://www.lifesci.sussex.ac.uk/home/Julian_Thorpe/tem22.jpg
Cytosol
 The gel-like fluid that surrounds the
organelles in the cytoplasm.
Vacuoles
 Storage
Lysosomes
 Decomposes/digests molecules
http://fig.cox.miami.edu/~cmallery/150/proceuc/tem.jpg
Ribosomes
 Makes proteins (protein synthesis)
(Tiny dots!)
Endoplasmic reticulum
 Transports molecules around the cell
 Rough E.R. has ribosomes on it
 Smooth E.R. lacks ribosomes
http://219.221.200.61/ywwy/zbsw(E)/pic/ech7-5.jpg
Golgi apparatus
 Packages molecules to be released
http://www.lifesci.sussex.ac.uk/home/Julian_Thorpe/tem12.jpg
Mitochondria
 Makes ATP energy from the sugars that
you ate earlier
http://images.google.com/imgres?imgurl=http://ebiomedia.com/prod/LC/images/UnitofLife_img_10.jpg&imgrefurl=http://ebiomedia.
com/prod/LC/LCcellunit.html&h=238&w=416&sz=19&hl=en&start=40&tbnid=oAv7kJ4T5Z0hFM:&tbnh=72&tbnw=125&prev=/imag
es%3Fq%3Dmitochondria%2BTEM%26start%3D20%26gbv%3D2%26ndsp%3D20%26svnum%3D10%26hl%3Den%26sa%3DN
November 2007
Cytoskeleton
 Supports cells with no cell wall (cytomeans cell)
 Microtubules: thicker, hollow tubes
 Microfilaments: thinner strands of protein
http://images.google.com/imgres?imgurl=http://www5.pbrc.hawaii.edu/allen/ch07/mimg/11-pmcyp7301163m.jpg&imgrefurl=http://www5.pbrc.hawaii.edu/allen/ch07/11-pmcyp7301163.html&h=711&w=640&sz=173&hl=en&start=3&tbnid=eKDoQPVtK0FPzM:&tbnh=140&tbnw=126&prev=/images%3Fq%3Dmicrofilaments%2BTEM%26gbv
%3D2%26svnum%3D10%26hl%3Den
Centrioles
 Helps the cell divide
View of one centriole
from the end.
http://upload.wikimedia.org/wikipedia/commons/thumb/1/10/Spindle_centriole_-_embryonic_brain_mouse__TEM.jpg/180px-Spindle_centriole_-_embryonic_brain_mouse_-_TEM.jpg
Chloroplasts
 Converts light to sugar molecules
(photosynthesis)
http://botit.botany.wisc.edu/images/130/Photosynthesis/Chloroplast_EN.gif
Where to find these
organelles:
Cytoskeleton: microfilamanets
Cytoskeleton: microstubules
Cytosol
Cytoplasm
Chloroplasts
Mitochondria
Centrioles
Vacuoles
Lysosomes
Ribosomes
Golgi apparatus
Endoplasmic reticulum
Nuclear pore
Nucleolus
Nuclear membrane
All
eukaryotic
cells
Nucleus
Animal
cells only
Cell membrane
Cell Wall
Plant cells
only
Where to find these
organelles:
Cytoskeleton: microfilamanets
X X
Cytoskeleton: microstubules
Cytosol
Cytoplasm
Chloroplasts
Mitochondria
Centrioles
Vacuoles
Lysosomes
Ribosomes
Golgi apparatus
Endoplasmic reticulum
Nuclear pore
Nucleolus
Nuclear membrane
Nucleus
Cell membrane
Cell Wall
X X
X
Animal
cells only
X
X X X X X X X X X X
All
eukaryotic
cells
X
X
Plant cells
only
Plant Cell & Animal Cell
Plant Cell
Animal Cell
Cell Video
http://aimediaserver4.com/studiodaily/vi
deoplayer/?src=ai4/harvard/harvard.swf
&width=640&height=520