Microbial Genetics Flashcards
Most complex microbial genome is a ____ genome. My can be single or double stranded ____ and ___
Viral
DNA
RNA
____ sense RNA genome means it is not translatable at that time
Minus
Eukaryotic cells can have ____ similar to bacteria
Plasmids
Chloroplast DNA, mitochondrial DNA, and nucleus DNA can all replicate ____ of each other
Independently
Prokaryotic DNA is ____ and they usually have plasmids as well
Circular
Prokaryotic cells have a ____ genome than eukaryotes but still too large to fit in the cell
Smaller
Bacterial chromosome replication:
____ ____ __ synthesizes the DNA.
DNA polymerase III
The enzymes involved in bacterial DNA replication are just different enough to eukaryotic enzymes, that you can ___ them with antibiotics. Especially the ______ enzymes in bacterial
Target
Topoisomerase I
_____ unzips the DNA helix
_____ synthesizes the RNA primer
____ ____ synthesizes the DNA
___ _____ removes the primer, repaired mismatches
Helicase
Primase
DNA Polymerase III
DNA Polymerase I
Bacterial chromosome replication takes place across two ____ ____ that move it opposite directions until they get all the way across the circular structure
Replication forks
Diagram of bacterial chromosome replication:
The ____ ____ is when the bacterial chromosome is midway through replicating. The ___ must be resolved to detach the two chromosomes and ____ repairs the nick
Theta phase
Nick
Ligase
Flow of generic information in microbes:
DNA is transcribed into _____ which is translated into ____
RNA
protein
Microbes have
tRNA, mRNA, rRNA, micro RNA, interfering RNA, riboswitches, antisense RNA, similar to eukaryotes. Microbes also have ____ over the gene expression
Control
Compare and contrast gene expression strategies in bacteria and eukaryotes:
DNA dependent RNA polymerase (DdRp) is and enzyme that polymerizes ___ and uses ___ as a template
RNA
DNA
RNA polymerase ___ makes the messenger RNA in eukaryotes. There is ___ RNA polymerase in prokaryotic cells
II
One
In prokaryotes, transcripts that encode for protein are ____ meaning you can have one long RNA that can be translated into multiple types of proteins
Polycistronic
In prokaryotes the transcription is controlled by variants of the ____ ___
In eukaryotes, there are ___ different types of transcription factors
Sigma factor
Many
Translation is the same in prokaryotes and eukaryotes but the ___ of the ribosome is different.
Prokaryotes: ___ + ___ = 70S
Eukaryotes: ___ + ___= 80S
Structure
30S 50S
40S 60S
Viral gene expression strategies:
All viruses have the ability to be able to express viral protein is completely dependent on the ___ ____.
Host cell
Bacterial gene expression control:
Most ___ ____ ___ interact with DNA in a sequence specific manner. They manly bind to the ___ ___ of DNA. ____ ____ frequently are binding sites for regulatory protein, allows for better affinity
DNA-binding proteins
Major groove
Inverted repeats
Outcomes of DNA binding proteins:
1. It may _____ a specific reaction on the DNA
2. They can block transcription called ___ ___
3. They can activate transcription called ___ ___
Catalyze
Negative regulation
Positive regulation
_____ is a cluster of genes arranged in a linear fashion whose expression is under the control of the single operator. The operator is located downstream of the _____. Transcription is ___ blocked when a repressor binds to an operator, which is called __ ___
Operon
Promoter
Physically
Negative control
Diagram of operon:
____ ____ binds to the promoter region in the operon
RNA polymerase
A repressor protein needs a _____ molecule to become active. The _____ is usually what the gene is transcribing, creating a ___ ___ loop.
Corepressor
Corepressor
Negative feedback
Diagram of operon off:
Another form of negative control:
The lac operon is normally off because the repressor protein is already in the correct ___ to bind. When ____ is added it pulls the repressor out of the way, which is called an ____. Ensure that the operon is only being utilized when ____ is present
Shape
Lactose
Inducer
Lactose
When lactose is ____, further enzyme synthesis is not necessary so the repressor binds to the operator again
Depleted
The ____ sits inbetween the promoter and the genes that need to be expressed
Operator
Positive control is implemented by regulators called ___ ____. They bind to the activator binding sites on the DNA and ___ transcription. Activator protein activity is modified by ____.
Activator proteins
Stimulate
Effectors
Promoters of positively controlled operons only ___ bind RNA polymerase. An ___ ___ helps RNA polymerase recognize the promoter by either causing a change in ___ ____ or by interacting directly with ___ ___. The activator binding site may be close to the promotor or several hundred bases away
Weakly
Activator protein
DNA structure
RNA polymerase
The maltose activator protein binds to ___ ___ to help it find the promoter. This only occurs when ___ is present which acts as an inducer.
RNA polymerase
Maltose
Diagram of when the activator binding site is farther away from the promoter:
Transcription is ____ to translation in bacteria. While transcription is still occurring, ribosomes bind and start translating. This is because there are no ____ ___ ____, allowing ribosomes to have excess to the newly transcribed RNA
Coupled
Membrane bound organelles
Quorum sensing was first discovered as mechanism, regulating light production in bacteria, including ____. The ___ operon encodes bioluminescence
V. Fischeri
Lux
Horizontal gene transfer diagram:
____ ___ uses donor DNA that is transferred into another cell. The donor DNA gets nicked and a single strand of that DNA finds a spot somewhere on the recipient DNA where there is a ____ sequence
Homologous recombination
Homologous
Diagram of genetic exchange:
Diagram of lysis and lysogeny:
When a virus goes straight to the lytic cycle, once and awhile a segment of the ___ DNA is packaged by a virus particle. This mistake turns into a ____ particle. This is called ____ transduction
Host
Transducing
Generalized
When a bacteriophage goes the lysogenic pathway, the virus is integrated into the host cell. If the host cell gets stressed, the virus will ___ itself out of the host genome and start to package into ___ ___. Sometimes a portion of the ___ DNA is exchanged for phage DNA and gets packed into viral particles. These can then undergo _____ transduction
Loop
Viral particles
Host
Specialized
The F plasmid is a circular DNA molecule that contains genes that regulate ___ ___. It contains several transposable elements that allow the plasmid to ___ into the host chromosome using ___ ____ (IS). It contains the ___ gene that encodes transfer functions.
DNA Replication
Integrate
Insertion sequences
tra
Picture of conjugation
Diagram of Hfr strains and chromosome mobilization:
When Hfr cells conjugate with F- cells, the F- cells remain ____
F-
Diagram of conservative and replicative transposable element:
Diagram of Hfr to an F- cell. The yellow portion is the F plasmid
