Bell Ringer Water, grass, rock, roaches, soil, telephone poles. Which are made up of cells? Why or Why Not? Complete sentences!!!!

Trivia How many muscles does an elephant’s trunk have in it?

Prokaryotes vs. Eukaryotes August 30, 2010

Cell Theory Has three parts: All living things are made up of cells Cells are the basic unit of structure and function in organisms All cells arise from existing cells

Why are cells so small? Does anyone have any explanations? Why don’t we have 100 big cells that make up the human body instead of 100 trillion?

Cells that are small Are more efficient Substances can enter and leave quicker Substances don’t have to travel so far to reach the center of the cell This is because of surface area! What’s surface area?

Surface Area Surface Area – the measure of how much exposed area a two or three dimensional object has For 2-D objects surface area and area are the same A = l x h For 3-D objects the surface area formula is different depending on the shape For cubes, Surface Area = 6(l2) For rectangles, SA = 2[(l x w) + (l x h) + (w x h)]

Surface Area The greater the surface area:volume ratio the more items can enter in and out of a cell effectively Volume determines how fast material can cross the membrane Surface Area determines how many items can move across

Dice…. I will give a group of four a die Measure and figure out the surface area and the volume

Watch This! http://www.youtube.com/watch?v=Jn9oJtXZYcU

Common Features of Cells Cell Membrane A layer that encloses the cell’s interior from its surroundings Cytoplasm A liquid substance that surrounds the organelles of the cell Cytoskeleton Microscopic fibers that help the cell maintain its shapes Ribosomes The organelle that makes proteins

http://www.cellsalive.com/howbig.htm http://www.cellsalive.com/cells/cell_model.htm

Prokaryotes Smallest and the simplest cells NO nucleus No other internal compartments Most common example: Bacteria Cause infection, cause food to spoil They do some good things too… 

Prokaryotes Can divide very rapidly Some do not need oxygen to survive Enzymes and ribosomes move freely around the cytoplasm Circular DNA molecule

Prokaryotes They have cell walls surrounding the cell membranes They don’t have cytoskeleton so it depends on the cell wall to hold its structure together

Cell Wall The cell wall is made up of sugars called polysaccharides connected to short amino acids Some prokaryotes also have a capsule that allows them to cling to anything (teeth, skin, food) Also made from polysaccharides

Eukaryotes Most cells you think about are eukaryotes Plants, animals, etc… A way to remember the difference…. EUkaryotes…YOU because you have eukaryotic cells