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.