-see more detail because they have a higher resolution
Comparing microscopes Light microscopes Electron microscopes Focus beams Lenses electromagnets Resolving power 200 nm 0.2 nm Color No staining required/can see color Requires metal dyes/black and white only Object Alive or dead Dead only Expense High school range/cheap Universities/high cost
SA = 24 in 2 V = 8 in 3 2” 2” 4” 4” SA = l x w x #of sides V = l x w x h SA = 96 in 2 V = 64 in 3 **Volume increases faster than the surface area. In this example the SA increased by 4 and the volume increased by 8.
How Big Is A Cell? OBJECT SIZE Eukaryotic 10-100 μ m Prokaryotic 1-5 μ m Nucleus 10-20 μ m Chloroplast 2-10 μ m Mitochondrion 0.5-5 μ m Large virus (HIV) 100 nm Ribosome 25 nm Cell membrane 7.5 nm DNA dbl. helix 2 nm H atom 0.1 nm
-plays important role in turgor (hardening of cells by the intake of water)
-prevents cells from taking in too much water
Homework: Outline the roles of extracellular components in plants (cell wall) and animals (extracellular matrix).
Summary of differences between eukaryotes and prokaryotes! Prokaryotic Cells Eukaryotic cells small cells (< 5 mm) larger cells (> 10 mm) always unicellular often multicellular no nucleus or any membrane-bound organelles always have nucleus and other membrane-bound organelles DNA is circular, without proteins (naked) DNA is linear and associated with proteins to form chromatin (not naked) ribosomes are small (70S) ribosomes are large (80S) no cytoskeleton always has a cytoskeleton cell division is by binary fission cell division is by mitosis or meiosis reproduction is always asexual reproduction is asexual or sexual