Prokaryotes vs. Eukaryotes
Eukaryotes
Size of cell
10-100mm in diameter
Nucleus
Has distinct nucleus
Covered by nuclear envelope
Gene expression
Transcription
carried out by 3 types of RNA polymerases
needs DNA sequence called the promoter to start
transcription factors needed to initiate process
undergoes RNA processing
takes out the introns and keeps exons
spliceosome catalyzes the reaction
Flagella
Complex
Bending movement
ATP driven
consist of multiple microtubules
DNA
Located in the nucleus
Linear
Complexed with "histones"
Organized into chromosomes
contains a number of chromosomes
Ribosomes
larger size
composed of 5 kinds of rRNA
80 kinds of protein
Cell division
Mitosis
Use special enzyme called telomerase
replicated chromosomes positioned in middle of cytoplasm then segregated
each daughter cell receives copy of original DNA
movements directed by microtubules
Prokaryotes
Size of cell
0.2-2.0 mm in diameter
Nucleus
No true nucleus
No membrane bound organelles
Gene expression
Transcription
Carried out by a single RNA polymerase
needs a DNA sequence called pribnow box to start
sigma factors are needed to start
doesn't have RNA processing
Flagella
not complex
Rotary movement
Proton driven
consist of 2 protein building blocks
DNA
Located in the cytoplasm
no cytoskeleton
no cytoplasmic streaming
Circular and has no ends
"naked" and has no histones
not formed into chromosomes
only one circular DNA molecule
Plasmids
Ribosomes
smaller size
composed of 3 kinds of rRNA
50 kinds of protein
Cell division
Binary fission
2 cells with identical genetic composition
chromosome is duplicated before division