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Prokaryotes don't follow normal genetics that eukaryotics follow. Why?
bacteria acquire genes from same species, adn are genetic scavengers that take genes form other species.
It's genetic composition is that of other species
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Bacteria have two types of genetic material
Explain the first
one large circular chromosome which has everything they need to live
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Bacteria have two types of genetic material
Explain the second.
- extrachromosomal (genes that are not located on the big chromsome)
- - come on plasmids
- - get small, linear pieces of DNA from their environment
- ex: broth has dead organisms with genetic material-- broken up
- --> can be taken to replace genes or enhance bacterial genome
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Flow of genetic information
Reproduction
- same as any cell
- --> parent to daughter
budding and cytosolic streaming --> no meiosis
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What bacteria can do that we can't do
recombination (possible due to simplicity/ occurs in many ways)
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How can recombination occur.
Name first.
-- acquire genetic material from environment that comes from bacteria that have died
----> type of lysing that exposes genetic material
----> if complete and intact, cell takes it up and expresses it
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How can recombination occur.
Name second.
- Acquire plasmids.
- --> can change entire phenotype based on that plasmid (which is acquired and trasferred)
ex: can develop penicillin resistance
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How can recombination occur.
Name third.
A very specific way
Pilus (hollow, short tube)
- -> used for direct, genetic transfer from a cell with a pilus to a cell with no pilus
- -> can be deliberate and direct
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More bacteria pick up genetic material __.
ad hoc (non-secific)
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DNA of bacteria
anti-parallel strands
there are some weird nucleotide bases that exist in archaea, etc., but we disregard them
still helical (circular, but helical)
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Prokaryotic DNA has no __.
- DNA associated proteins
- - no histones (no compacting)
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If there are no histones, how does the bacterial chromosome exist?
the bacterial chromosome is free and loose in tehe nucleoid region
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Explain what the nucleoid region consists of.
wherever the DNA chromosome may be at a time
the region is not static
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Enzymes that replicate DNA
- the same in Euk as prk with the same funciton
- - DNA Pol: reads and writes in teh 3' to 5' direction, but adds in the 5' to 3' direction
helicases
ligases
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DNA Replication
- as a single strand, it is __.
- __ stablilize it
very strong
proteins stabilize it to keep it straight
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What is the problem with DNA replication?
Where does the circle begin and end?
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Basic mechanism for all in the Domain Bacteria
- 2 regulatory sequences
- --> ORIs= tell DNA polymerase where to start replicating DNA material
- --> termination = tells it this is the end sequence
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So, what happens?
- we open up the sequence in a circle, giving you no necessity for a leading and lagging strand
- --> DNA polymerase binds as if each strand is a leading strand
- --> DNA polymerase does this and also binds as if they were a lagging strand
- --> they are each their own leading and lagging strand
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Both DNA pol exit at the __.
__ is right behind. When finished, __.
__ creates the helix and is the last enzyme.
termination of replication
DNA ligase
strands separate
DNA helicase
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Transcription: __
Bacteria have the __ and __.
DNA-->RNA
same function
the different sequence
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When we talk about our genes, each gene essentially has __.
What are monocystronic genes?
one product
we have this because we have a lot of space in the genome, a lot that is not used, a lot of archaean genomes, a lot of regulatory components
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For prokaryotes, it is not __.
What is polycystronic?
- complex
- some genes have two mes., others 3, 4, etc.
- not a lot of room for storage or history, etc.
- - number of products depends on gene
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