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Bacteria do not have sterols (cholestrol) in their plasma membrane. What do they have and why?
Haponoids to stabilize membrane.
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What is the function of the plasma membrane?
- Serve as a selective permeable
- Barrier for materials entering and exiting
- Retains cytoplasm
- Transport system for nutrient uptake and waste excretion, and protein secretion
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What is the plasma membrane of Archaea?
- Have no phospholipid bilayer but a single layer
- Ether-linked molecules (glycerol)
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Percentage of water in cytoplasm, refered to as the internal matrix of the cell contained within the plasma membrane..
80%
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What are the major structures of the cytoplasm?
- Highly organized protein location has
- Dna, ribosomes and inclusions
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as of 2001, what does the cytoplasm known to have?
the Cytoskeleton.
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what kind of filaments does it have?
similar matrix of Microfilaments, microtubules and intermediate filaments.
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Does the matrix contain proteins not found in eukaryotes and serve as scaffolding for cytoplasmic ocmponents and help bacteria maintatin its shape and aid in division?
Yes
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What are the Bacteria and Archaea Actin homologues of the cytoskeleton?
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What is the tubulin homologue of Bacteria and Archaea?
FtsZ
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What is the intermediate filament homologue?
Crescentin (Caulobacter cresentus)
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What is the composition of Ribosomes?
Protein and ribonucleic acid and is the site for protein synthesis located in the cytoplasmic matrix and attached to the plasma membrane.
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What is required of the ribosomes for synthesis of proteins to remain in the cell?
to be in the Matrix.
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What happens if the Ribosomes are attached to the plasma membrane?
The proteins synthesized get transported outside the cell.
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what is the size of procaryotic ribosome?
70S (Svedberg units) smaller than eukaryotic ribosomes (80S). 30 +50 (Bacterial Ribosome?
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What is the difference between Bacterial and eukaryotic rRna?
16s archaeal rna is more similar to 18s rRna not 16s rRna.
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What does the procaryotes chromosomes look like in the nucleoid?
- Double stranded and circular.
- some have linear chromosomes
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Which bacteria have linear chromosomes?
- Borrelia.
- Branched is rare.
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Supercoiling
- Dna wound into a smaller unit
- dna is twisted in the opposite direction from the right-handed double helix.
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What helps supercoil the chromosome?
Condensin and Rna
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What do proaryotic chromosomes not have?
Histones
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What are the two main types of supercoiling?
Positive supercoiling and negative supercoiling
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Positive supercoiling
Is when additional turns are introduced and left-handed supercoiling; overwinding.
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Negative supercoiling
Results when addtional turns are removed and right-handed supercoiling; underwinding.
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Supercoiling in bacteria has to tenzyme types.
Topoisomerase 1 and 2
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Type 1/ Toopoisomerase 1:
- Cuts one strand of Dna; reanneals the strand and relaxes the helix
- Also used to reduce some of the tensional strain produced by the unwinding of Dna
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Type 2/ Dna gyrase:
- cats both strands of Dna; reanneals the strands
- allows unbroken strands of dna to pass through
- used to introduce supercoils, knots; important in catenation
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Supercoiling is accomplished by the use of archaela...
histone proteins
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Archaelal histones + Dna=
archaeal nucleosome
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similar to eukaryotice nucleosome h3 and h4 is
archaeal nucleosome
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What are the five types of supercoiling nucleosomes?
H1, h2a, h2b, h3, and h4 form eight molecules, 2 from each except h1.
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Where does replication begin in bacteria/eubacterial genetics?
the Ori site or initiation of replication (origin of replication)
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What does the Ori site use?
a multi-enzyme replication complex, which binds to the the origin of replication and initiates unwinding and separation of the two dna strands.
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Theta replication
replication method of bacterial chromosomes
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What method is used for replication of a bacterial plasmid?
the rolling circle method.
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