Module 8 Lec 1 Flashcards
What do prokaryotes lack?
Prokaryotes lack a nuclear membrane and other membrane-bound organelles.
Which domains include prokaryotes?
Prokaryotes are found in the domains Bacteria and Archaea.
How do bacteria compare to other organisms on Earth?
Bacteria outnumber all other organisms on Earth.
What allows bacteria to live in almost any environment?
Bacteria have remarkable metabolic diversity.
How do bacteria reproduce?
Bacteria divide by binary fission.
How fast can bacteria replicate?
Bacteria can replicate rapidly, with a second round of replication starting before the first is complete.
How many chromosomes do bacteria have?
Bacteria usually have one, circular chromosome, making them haploid.
What is the structure of the bacterial chromosome?
The bacterial chromosome folds to form a nucleoid body.
Where does chromosomal replication begin in bacteria?
Replication begins at the origin of chromosomal replication (oriC).
How is the gene density in bacterial chromosomes?
Bacterial chromosomes have high gene density and lack introns.
What are insertion sequences (IS) in bacteria?
Insertion sequences (IS) are transposable elements that can move within the genome
What gene do bacterial insertion sequences (IS) contain?
Insertion sequences contain the gene for transposase, the enzyme that catalyzes transposition.
What are plasmids in bacteria?
Plasmids are small, circular DNA molecules that are not essential for reproduction or growth
What do plasmids often carry in bacteria?
Plasmids often carry genes for antibiotic resistance, host invasion, and pathogenesis.
Why are mutations in bacteria always “homozygous”?
Bacteria are haploid, so mutations in their single chromosome are always expressed without a second allele to mask them.
What are some results of mutations in bacteria?
Mutations can:
Change colony morphology
Confer resistance to antibiotics or bacteriophages
Create auxotrophs (unable to synthesize a specific compound)
Cause IS insertions, leading to spontaneous mutations
What is vertical inheritance?
Vertical inheritance is the transmission of genetic material from parent to offspring across generations (e.g., Generation 1 → Generation 2 → Generation 3).
What is horizontal inheritance?
Horizontal inheritance is the transfer of genetic material between individuals of the same generation (e.g., Generation 1 ↔ Generation 1). It can occur via processes like conjugation, transformation, or transduction in bacteria.
