Prokaryotic cells Flashcards
What was the first fossil evidence of life on earth?
Prokaryotes around 3.5 billion years ago
What are the two domains of Prokaryotes?
Bacteria and Archea
How long did it take for earth to have more life than juts prokaryotes?
1.5 Billion years
What does the key word “Pro” mean?
First/before
What does the key word “karyon” mean?
Kernel/nucleus
What does the key word “eu” mean?
True. `
Why are PROkaryotes and EUkaryotes named differently?
Prokayotes do not have a nucleus.
What is a Nucleus?
Genetic material as dense linear chromosomes enclosed by a membrane.
What do prokaryotes have in the place of a nucleus?
They have a dense, circular ring of DNA not enclosed by a membrane, called a NUCLEOID region.
Do Prokaryotes and eukaryotes have plasmids?
No, only prokaryotes
What is a plasmid?
A plasmid is a small ring of DNA that contains a few extra genes a cell can use to gain a competitive advantage.
Do Prokaryotes reproduce using mitosis and meosis like eukaryotes? if not how do they?
Nope. They use the following: - Binary Fission - Transformation - Transduction - Conjuction
What is Binary fission?
The most common method of reporoduction for prokaryotes.
- New DNA is synthesized.
- When the chromosome duplicates the cell splits
- The rate of binary fission is denpent on the environment.
What is transformation?
It is the uptake of “naked” DNA released from dead bacteria by a living prokaryote.
What is transduction?
The transport of DNA between prokaryote cells by viruses (Bacteriophages)
What does the root word (Phage) mean?
Eat
What is conjunction?
It is when one prokaryote latches onto another with a string like structure (Pilus) and transfers DNA.
Is conjunction unidirectional or bidirectional?
Unidirectional, from pilus-producer to receiver.
Primarily transporting plasmids
What is horizontal transfer and why dose it lead to rapid adaptation to antibiotics?
‘Horizontal’ means transfer between individuals of the same generation, they don’t need to be related.
Allows for the spread of favorable adaptation.
What is a exsample of horizontal transfer?
Conjunction.
What is vertical transfer?
The transfer of genetci material from parent to offspring between generations.
example: Binary fission.
Are the call walls of prokaryotes the same as eukaryote cell walls?
No, Prokaryotes do not have cell walls.
What is found in the cell membrane of prokaryote?
Peptidoglycans.
What is the purpose of a cell wall?
TO prevent a a cell from going boom when placed into a hypotonic solution.
What is a gram positive prokaryote?
They have peptidogycan wall in contact with external medium which traps purple stain.
What is a gram negative prokaryote?
they have lipopolysaccharide layer outside the cell wall, and thus do not absorb stain readily.
True or false:
Gram negative cells are usually more pathogenic.
True
The outer layer oflipopolysaccharide can contain toxins and also resist action of antibiotics.
True or false:
Prokayotes do not have membrane enclosed organelles
True.
They have no nucleus, mitochondria, or chloroplasts.
True or false:
Prokaryotic cells are usually larger than eukarotes.
False,
They are usually a lot smaller.
1-5pincometers in size.
True to false:
Prokaryotic cells are not mobile and form larger units such as tissues, and organs.
False:
They are mobile and move around using flagella.
What does the root word (Flagellum) mean?
whip
How fast can some bacteria move?
50 body lengths per second.
True or false:
Many prokaryotes demonstrate taxes
True
What is Taxes?
The moment away from or towards stimulus.
As well as structural diffrences what is another MAJOR difference between prokarotes and eukaryotes?
Their metabolic pathways.
What is metabolism?
Chemical pathways used by living organisms to build up molecules (anabolism) or the break down of molecules to release energy (catabolism)
What does the key word (Meta), (ana), and (cata) mean respectfully?
meta = change ana = up cata = down
What are the the three basic needs for metabolic activity?
Water
Carbon
Energy
What are Photoautotrophs
They use light energy, and CO2
What do the root words
(Photo)
(Auto)
(Troph)
photo=light
auto=self
troph=eat
What are chemoautotrophs?
Use energy obtained by oxidizing inorganic chemicals, and CO2
many are prokaryotes.
What are Photoheterotrophs?
They use light energy, but get carbon from organic molecules.
very few are prokaryotes
What does the root word hetero mean?
Different.
What are chemoheterotrphs?
Use organic molecules for both energy and carbon source.
Animals, fungi, many prokaryotes, few plants
What are the two Domains of Prokaryotes? How did we come to this understanding?
We started looking at the RNA structures of Prokaryotic.
two domains:
- Bacteria/Eubacteria (Eu=true)
- Archaea (Arch=ancient/original)
What is the main difference between Eubacteria and Archaea?
Archaea lack peptidoglycan within their cell walls
True to false:
Archaea do not respond to antibiotics.
True.
true to false:
Archaea are primarily extermeophiles
True.
What does the root word (Phil) mean?
Love/prefer/attached to
What are methanogens?
Archaea that live in oxygen free environments.
They produce methane as a waste product.
What are Halophiles?
Archaea that live in very salty environments
What does the root word (halo) mean?
Salt (where salt is)
as in any ionic cystalline compound.
What are thermophiles?
Archaea that live in very hot environments
True or false:
bacteria exist in 5 major clades.
True
What are proteobacteria?
A large and metabolically diverse group of gram negative bacteria.
What clade does ‘Rhizobium’ exist in?
what is it?
Proteobacteria
- endosymbiotic mutualist
What does Rhizobium do that is important to the environment?
fixes atmospheric nitrogen.
What clade does Escherichia coli exist in?
Proteobacteria
What are Chlamydias?
a Bacterial clade that can only live within the cells of animals.
what are spirochaetes?
A bacterial clade of quite long(up to 0.25mm) helical bacteraia that swim by spiraling.
What bacterial clade is responsible for syphilis and lyme disease?
Spirochaetes
True or false:
Gram positive bacteria form their own Clade.
true
What role do gram positive Bacteria play in the environment?
They are important decomposers
What is the smallest know cell?
mycoplasmas
- gram positive Bacteria that is 0.1 pecometer in length.
What clade is Anthrax a part of?
Gram positive Bacteria
What causes botulism?
Clostridium botulinum
a gram positive Bacteria
What is especially sepetable to botulism?
Waterfowl due to fly larvae’s ability to accumulate C. Botulinum
What do humans use that is derived from botulism?
Botox
What are Cyanobacteria?
A bacterial clade that includes the only prokaryotes that produce oxygen through photoautotrophy, although some fix atmospheric nitrogen as well.
What is the common name for Cyanobacteria?
Blue green algae
What are the three major roles that Prokaryotes play in the environment?
- They are vital decomposers
- They are important producers of oxygen and nitrogen
- They are the primary producers that supply the food web in the place of plants.
True or false:
many Prokaryotes are beneficial inhabitants of eukaryotes.
True.
