Bacteria Flashcards
1
Q
two types of cells
A
eukaryotic cell and prokaryotic cell
2
Q
three domains of life
A
eukarya, archaea, bacteria
3
Q
prokaryotes
A
- are microscopic organisms that contain no nucleus
- they include the bacteria and archaea
- prokaryotes are the most abundant and diverse organisms on earth
3
Q
archaea
A
- no known pathogens
- some archaea live in extreme environments and are called extremophiles
- extreme halophiles = high saline environments
- extreme thermophiles = hot environments
4
Q
general features of a bacterial cell
A
- lack nucleus but have nucleoid region
prokaryotes - have small genomes
- one big ring in nucleoid region = chromosome
- smaller rings = plasmids - ribosomes are smaller and have a different makeup than the ribosomes of eukaryotes
- different protein and RNA content - the genes for these rRNAs are often used for classification
5
Q
bacterial genomes
A
- the prokaryotic genome has less DNA than the eukaryotic genome
- the typical prokaryotic genome is a ring of DNA (a circular chromosome) that is not surrounded by a membrane and that is located in a nucleoid region
- some species of bacteria also have smaller rings of DNA called plasmids
6
Q
smaller rings of DNA in bacterial genomes- plasmids
A
- plasmids can replicate independently of the chromosome
- often have genes useful for the survival of the bacteria (e.g. for resistance to antibiotics, or for the ability to metabolize a particular nutrient like lactose)
7
Q
prokaryotes divide by
A
binary fission
8
Q
eukaryotes dived by
A
mitosis/meiosis
9
Q
bacterial classification - historically
A
- microscopic observations (e.g. shape, response to stains)
- biochemical characteristics (& growth conditions)
10
Q
bacterial classification - more recent
A
- serological characterization (using antibodies/immune response)
- compare DNA sequences (% similarity of rRNA genes)
- for clinical analysis, we can identify bacteria using PCR (a method to amplify DNA)
11
Q
bacterial morphologies - coccus
A
circle/sphere
12
Q
bacterial morphologies - bacillus
A
rod shaped
13
Q
bacterial morphologies - vibrio
A
curved rod shape/comma
14
Q
bacterial morphologies - spirillum
A
squiggly/ spiral