Cells Organized labor at its finest! www.freelivedoctor.com
What is the importance?
Division of labor
Increased Surface Area
No membrane bound organelles
DNA uncomplexed by histones
Prokaryotes can live in the coldest, hottest, most acidic and most highly pressurized environments.
They can live in places such as beneath the earth in bare rock, under glaciers, floating around in clouds and miles down on the sea floor at temperatures greater than 100 C.
Types of Prokaryotes
Most Archaea are anaerobic (living in the absence of Oxygen)
Many live in uncommon and extreme environments, i.e. hot springs, Arctic ice floes, highly saline waters and highly acidic or alkaline soils.
Nearly half of the known Archaea are Methanogenic, meaning that they give off methane as a by-product of their metabolic activity.
The Archaea have a diverse variety of shapes and exist not only as rods and dots (cocci) like bacteria but also as triangles, discs, plates and cup-shapes.
Bacteria live mostly on the surfaces of objects where they grow as colonies.
Bacteria are important in making soil, feeding cows, controlling insects, making medicines, making bioplastics, making plants grow, degrading pollutants such as oil and plastics as well as in causing disease.
Most bacterial species are un-named and unidentified
Tens of thousands of species have been isolated
There are more than 15,000 known species of bacteria living in the sea
Most famous is E.coli (Escherichia coli)
E. coli www.freelivedoctor.com
plasma membrane constitutes #2
pili (for adherence to cells)
flagella (for propulsion through aqueous environment)
chemistry similar to ours
Some strains frequently cause diarrhea in travelers, and it is the most common cause of urinary tract infections
One strain, designated O157:H7, is particularly virulent and has been responsible for several dangerous outbreaks in people eating contaminated food (usually undercooked hamburger).
Several important drugs (insulin, for example) are now manufactured in E. coli
Has to be folded
histones (positively charged proteins)
huge number of proteins
transporters (nutrient carriers)
receptors (signal transduction)
lipids and protein
semi-permeable (polar and charged ions cannot cross freely)
chromatin vs. chromosomes
nucleolus has RNA
histones: proteins that are positively charged that wind up DNA
protein synthesis occurs here for those proteins that will be routed out of cell
metabolism of drugs and toxic substances
Cellular post office
Proteins synthesized in the ER are packaged with extras such as
SO 4 2- , carbohydrates, lipid moieties
Then, the proteins are directed to either the cell membrane to outside the cell or within the cell.
In other words, the proteins are flagged for their next destination
has its own DNA
uses nutrients to make energy
In plants, chloroplasts makes sugar from sunlight
Lysosomes (Animal Cells)
Recycling centers can breakdown proteins
in plant cells these are vacuoles
Breakdown H 2 O 2
internal organization, assists the plasma membrane in retaining cell shape, and allows the cell to move
rods from tubulin
Actin: protein filament for cell rigidity
Myosin: moves along actin using ATP
Contains DNA surrounded by protective shell or capsid
Uses host cells enzymes and ribosomes for replication
Lysogenic phase: viruses may remain dormant inside host cells for long periods. There is no obvious change in their host cells
Can enter the lytic phase: new viruses are produced, assemble, and burst out of the host cell.
The cell is killed and other cells are infected
Smallpox, common cold, chickenpox, influenza, shingles, herpes, polio, rabies
Viruses that infect bacteria
Commonly used in molecular biology
DNA isolated from tissue---> Packaged into bacteriophage DNA---> Bacteria culture grown and infected with bacteriophage---> DNA of interest is replicated and studied either on DNA level or protein level