Proteoliposomes are artificial membrane vesicles of ( ) and ( ) that are of enormous value in studying membrane proteins involving solute transport and electron transport.
When one keeps the internal concentration of a solute higher than the external concentration by several orders of magnitude, one requires energy. The source of energy can be either ( ), ( ), or ( ).
Chemical, light, electrochemical
When we talk about ABC transporters, ABC stands for...
ATP Binding Cassette
There are two transport systems for K+ in bacteria: TrK system and Kdp system. They differ in their (___) for K+.
*high affinity, needs more energy...demands more energy*
When glucose is transported from outside to inside of E. coli, it is phosphorylated. So the transported product inside the bacteria is (___), not glucose. This type of transport is called (___).
glucose-6-phosphate, Pts, or group translocation.
(____) are an important way by which bacteria become resistant to antimicrobial agents, such as antibiotics, dyes, detergents, disinfectants, and antiseptics.
Drug Export System
An example of an (____) resistance system in Mycobacterium tuberculosis is the TAP system.
*pumping out TAP (a transporter of aminoglycosides and tetracycline, efflux**
List five ways that bacteria do for solute transport
Symport, Uniport, Antiport, ATP dependent, Phosphotransferase
When one wants to differentiate the source of energy (ATP or proton potential) for solute transport, one has to inactivate ATP synthase. Why is that?
Because ATP and protons are interconvertible, you need to shut down the synthesis inorder to utilize proton potential.
If you want to translocate any protein across the cell membrane (or outer membrane), you need always energy.
Proteins are pretty big, so there is no way to be translocated across the cell membrane without their being denatured
The amino acid sequence of a protein contains all the folding information of the protein.
Some bacteria secrete proteins directly into host cytoplasm.
Cell inside is more reducing (low redox potential) than the outside.
There are two main protein export pathways in bacteria. One is ( a ) system and the other is ( b ) system. ( a ) system translocates proteins in an unfolded form, while ( b ) translocates fully folded proteins
The proteins that are translocated by the Sec system are synthesized with a leader peptide sequence. The leader peptide sequence consists of a basic amino-terminal end that has positively charged ( ) and ( ) residues, followed by a ( ) region, and finally an uncharged C-terminal region, which contains a recognition site for a ( ).
Lysine, Arginine, Hydrophobic, Peptidase
For the cytoplasmic membrane -bound proteins, there are always internal ( ) regions of the protein that stop translocation and anchor the protein into the membrane because they bind to the lipid.
A major chaperone protein in E. coli is ( a ). ( a ) binds to the mature domain (not leader peptide) of the preprotein and prevents premature folding in the cytoplasm and aggregation.
A transcription factor is most likely a membrane protein. Dna in the cytosol
Bacteria often use secondary messengers representing environmental signals.
Secondary messengers-converge of primary signals
Obligatory anaerobes sense oxygen using a common transcription factor, FNR.
Glucose is the best carbon source for E. coli. So, glucose will repress the utilization of all the other carbon sources
Ecoli catabolite repression
Bacteria sense their environmental changes by recognizing signaling molecules and therefore there must be cellular components to bind to such signaling molecules (ligand).
Several bacteria undergo sporulation when faced with nutrient excess.
False, sporulation occurs when there is a lack of nutrients
All the environmental signaling molecules go into the cytoplasm in order to trigger appropriate adaptation mechanisms in bacteria.
In two-component systems, the sensor protein is always a transmembrane protein. One protein will sense the outside and transport transmembrane.
Upon binding to signaling molecules, transcriptional regulators (or sensor proteins in two-component systems) undergo conformational changes (that is, there must be two protein forms in each case). Any transcription factors have two forms activate or repressed, the ligand binds to proteins (TF) to activate or deactivate TF.
When bacteria encounter chemo-attractants (food), they tumble rather than swim.
The regulation by altering protein’s activity is faster than that by changing the transcription level of the protein
***if you don’t need a protein right now, what to do? Don’t make mrna for protein, or make mrna and stop there…or mrna….don’t make protein…you regulate transcription to not make protein..most regulation is at the transcription level….the protein is already made. Proteins sense environment go thru conformational change.
The reactions catalyzed by regulatory enzymes are usually at a metabolic branch point.
Regulatory enzymes often catalyze reactions that are physiologically irreversible.
A positive allosteric effector would increase the Km of its protein. Increase activity, should lower km activity good for protein, kcat high good for enzyme
When glucose is added to E. coli culture media, you will see a lot of glucose inside the bacterial cell.
In E. coli, glucose the best carbon source so if glucose is around, it represses the utilization of other carbon sources.
In E. coli, cAMP receptor protein is the transcriptional activator involved in catabolite repression. So, the effector (ligand) of the protein is glucose
When E. coli cells see lactose (a decent carbon/energy source) outside, they always express lactose-utilization enzymes.
RNA polymerase prefers some DNA sites to bind to.
A transcription factor binds to target DNAs by recognizing a specific sequence.
Transcriptional activator helps RNA polymerase transcribe and repressor inhibits RNA polymerase from transcription
In an operon, the binding site of a transcriptional activator always precedes the site for RNA polymerase (promoter).
In an operon, the binding site of a transcriptional repressor usually precedes the site for RNA polymerase (promoter).
Let’s say you know that the transcription of an operon strictly requires a transcriptional activator. Then the promoter for the operon is strong (& ideal).
How do you call DNA site to which a repressor binds?
The normal flora are always beneficial.
Temperature can be a signal for virulence gene expression for pathogens.
Endotoxins are secreted in soluble form by live bacteria.
An enterotoxin is a protein toxin released by a microorganism in the intestine.
Many bacteria can sense quorum and do so by direct cell-cell communication using pili.
If the genes for luminescence in a bacterial species are under the control of quorum sensing signal, luminescence is dependent upon cell density.
If the genes for luminescence in a bacterial species are under the control of quorum sensing signal, luminescence happens onlyin high cell density above certain concentration.
The production of the same AI-2 by different types of bacteria in the same community is one way for the bacteria to engage in (____) communication
This term is for a community of microorganisms immobilized and living on a solid surface exposed to air or liquid. The obvious advantage would be a formation of food webs via the coordination of different types of microorganisms. What is this?
This bacterium, ( ), killed 75-200 million European people (one-third of the population at that time) in 1347 to 1353, known as the Black Death.
This bacterium, ( ) was first isolated by Italian anatomist, Filippo Pacini and also by Robert Koch as the cause of cholera
This bacterium, ( ) is an opportunistic pathogen, meaning that can cause disease to an immunocompromised person, but not a healthy person. It typically infects lung, so it is a threat especially to a patient having cystic fibrosis
( ) species cause gastroenteritis, enteric fever, and septicemia (blood infections)
( ) species cause shigellosis and produces shiga toxin
This bacterium, ( ) is the causative agent of whooping cough. When you were very young, you probably got an immunization shot against this agent.
This bacterium (___) is the most common cause of staph infections, though it may exist as a commensal on human skin.
(___) is the causal agent of Crown Gall disease (the formation of tumors) in over 140 species of flowering plants. The bacterium has a mega-sized Ti plasmid (tumor-inducing plasmid).