BIOL107 Lecture 7: Prokaryotic Cell Interiors
SchoolUniversity of Alberta
DepartmentBiology (Biological Sciences)
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Biol 107-Lecture 7-Prokaryotic Cell Interiors
Prokaryotic Cell Interiors
• 70% of the cell “contents” is water
• Cytoplasm-everything inside the plasma membrane.
• Cytosol-the fluid inside the plasma membrane. Some solutes are in the cytosol,
but aren’t part of the plasma membrane.
Chromosome (feature of the cell)
• Circle of double stranded DNA (0.5-7.0Mb long) and most bacteria have 1 copy
• The strand is not open-ended and when it’s untangled, it would be a loop. There
are some exceptions.
• The chromosome contains all the genetic information needed to function and
• Every structure in a cell is encoded in the chromosome
• Chromosomes are replicated during cell divisions
• The main function of the DNA is having a portion of gene which is transferred to
RNA for the making of proteins.
• The chromosome may be accompanied by some RNA and protein are contained
in the nucleoid which is like the nucleus of animal cell except that it has no
• They’re usually small but can be quite large also.
• They are circular dsDNA but are independent of the chromosome and replicate
• Can be 1-1000 copies of the same plasmid per cell
• They also carry at least one gene that regulates its own copy
• There are 2 different types of plasmids which are R-plasmids and F-plasmids
• The R-plasmids confer the resistance of the bacteria to antibiotics. The F-
plasmids confer the ability to transfer plasmids through the use of sex pili
• However, some R-plasmids also encode the information to make a sex pili and
the F-plasmids also have the R-plasmids in it.
• Bacteria with the F-plasmids can copy themselves over to a new host which can
then produce the R-plasmids—this plays a big role in the spread of resistance of
antibiotics among bacteria.
• A cell can have more than one type of plasmid only if they’re compatible, but
some cells aren’t compatible so they can’t coexist together.
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