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 membrane-bound 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 Eukaryotic cell Simple or Complex? Size of Cell? Unicellular, Multicellular, or Both Any membrane-bound organelles? What does the DNA look like?

Comparing prokaryotes to eukaryotes Prokaryotic cell Eukaryotic cell Simple or Complex? Simple Complex Size of Cell? 1 – 2 μm Typically 10x larger Unicellular, Multicellular, or Both Unicellular Both Any membrane-bound organelles? No Yes What does the DNA look like? Tangled loop Chromosomes

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%20pore%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=/images%3Fq%3Dmitochondria%2BTEM%26start%3D20%26gbv%3D2%26ndsp%3D20%26svnum%3D10%26hl%3Den%26sa%3DN November 2007

Cytoskeleton Supports cells with no cell wall (cyto- means 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-pmcyp730116-3m.jpg&imgrefurl=http://www5.pbrc.hawaii.edu/allen/ch07/11-pmcyp730116-3.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: Cell Wall Cell membrane Nucleus Nuclear membrane Nucleolus Nuclear pore Endoplasmic reticulum Golgi apparatus Ribosomes Lysosomes Vacuoles Centrioles Mitochondria Chloroplasts Cytoplasm Cytosol Cytoskeleton: microstubules Cytoskeleton: microfilamanets Plant cells only Animal cells only All eukaryotic cells

Where to find these organelles: Cell Wall Cell membrane Nucleus Nuclear membrane Nucleolus Nuclear pore Endoplasmic reticulum Golgi apparatus Ribosomes Lysosomes Vacuoles Centrioles Mitochondria Chloroplasts Cytoplasm Cytosol Cytoskeleton: microstubules Cytoskeleton: microfilamanets Plant cells only X Animal cells only All eukaryotic cells

Plant Cell & Animal Cell

Cell Video http://aimediaserver4.com/studiodaily/videoplayer/?src=ai4/harvard/harvard.swf&width=640&height=520