1. A population of bacteria decreases by 5.288% every five minutes.
a. Write a modeling function for the bacteria population, leaving the initial population alone
-----For this i have P(t)=Initial(1-0.05288)^t
b. After 6 hours, a single bacteria remains. What was the initial population?
----I have: 1=Initial(.94712)^360min(6hrs). I got 312030668.2
c. Assume that the bacteria were floating on a noodle in some chicken nooodle soup in the NW dining hall. As the bacteria voted eachother off the noodle, it was televised by the BBC. THe BBC Later determined that the ratings were (in millions): 1 initally, 2 after 1 hour, 5 after 2hrs, 10 after 3hrs, and 17 after 4hrs. Write a function that models the ratings exactly
d. Re-write the function from (c) so that your time unites are minutes instead of hours.
e. Express the number of bacteria on the noodle as a function of the ratings
THanks for anyone who can help, and can you say what you did also?
Pre-Calc + Bacteria Problem?
Unless your t stands for the number of 5 minute intervals, you should make the exponent be t/5 not t.
bleeding heart
Thursday, May 7, 2009
A bacteria culture grows with constant relative growth rate. After 2 hours there are 700 bacteria and after 8?
A bacteria culture grows with constant relative growth rate. After 2 hours there are 700 bacteria and after 8 hours the count is 70,000.
a) Find the initial population.
P(0) = ? bacteria
(b) Find an expression for the population after t hours.
P(t) = ?
(c) Find the number of cells after 7 hours.
P(7) = ? bacteria
(d) Find the rate of growth after 7 hours.
P'(7) = ? bacteria/hour
(e) When will the population reach 200,000?
t = ? hours
A bacteria culture grows with constant relative growth rate. After 2 hours there are 700 bacteria and after 8?
let A = initial count of bacteria
y = Ae^(kt)
700 = Ae^(2k)
7000 = Ae^(8k)
dividing...
10 = e^(6k)
e^k = 10^(1/6)
thus
700 = A 10^1/3
A = 700/[10^1/3] = 324.9112 or 324
y= A (10)^(t/6) .... this is the equation...
plug in t = 7... to get c
differentiate to get d.
y' = A/6 (10^(t/6)) * ln 10
when y = 200000 solve for t.
200000 = A (10)^(t/6)
§
Reply:a) you only started with one bacteria, therefore the initial population is one
b) you have to find the average rate of change (ARC), i.e. slope of the expression. To do so, you make the given info coordinate points
(2,700)
(8,70000)
ARC: (70000-7000)/(8-2)=11550
P(t)=11550t+b
11550(2)=23100
23100-700=22400
Final expression:
P(t)=11550t - 22400
c) Pop 7 into t and solve
d) I would think you would take your answer from C and divide that by 7, but I don't know for sure.
e) put 200000 in as P and solve for t.
a) Find the initial population.
P(0) = ? bacteria
(b) Find an expression for the population after t hours.
P(t) = ?
(c) Find the number of cells after 7 hours.
P(7) = ? bacteria
(d) Find the rate of growth after 7 hours.
P'(7) = ? bacteria/hour
(e) When will the population reach 200,000?
t = ? hours
A bacteria culture grows with constant relative growth rate. After 2 hours there are 700 bacteria and after 8?
let A = initial count of bacteria
y = Ae^(kt)
700 = Ae^(2k)
7000 = Ae^(8k)
dividing...
10 = e^(6k)
e^k = 10^(1/6)
thus
700 = A 10^1/3
A = 700/[10^1/3] = 324.9112 or 324
y= A (10)^(t/6) .... this is the equation...
plug in t = 7... to get c
differentiate to get d.
y' = A/6 (10^(t/6)) * ln 10
when y = 200000 solve for t.
200000 = A (10)^(t/6)
§
Reply:a) you only started with one bacteria, therefore the initial population is one
b) you have to find the average rate of change (ARC), i.e. slope of the expression. To do so, you make the given info coordinate points
(2,700)
(8,70000)
ARC: (70000-7000)/(8-2)=11550
P(t)=11550t+b
11550(2)=23100
23100-700=22400
Final expression:
P(t)=11550t - 22400
c) Pop 7 into t and solve
d) I would think you would take your answer from C and divide that by 7, but I don't know for sure.
e) put 200000 in as P and solve for t.
Bacteria help!!?
OKay! For my AP Biology class, we have to make up an experiment for an inquiry project. Mine was studying how much bacteria grew after being cleaned with brand name and generic brand cleaning products.
We did our 1st set of testing the other day (Tuesday) and today we examined it.
The bacteria or unknown growing bacteria of culture we took
it looks like
lots of small white fuzzy little colonies of bacteria or I have no idea what.
I have been trying to figure out what the bacteria is by looking at it.
Anyone have any ideas what the bacterica or culture could be. I have been looking on line fore a few hours nows and have gotten not so far.
So I would like peoples ideas on what it could be or if you know a good site I can look at!
Thanks!
Bacteria help!!?
Identifying bacterial species is a nearly impossible task unless you can narrow it down based on the source. If it came from your skin it is most likely Staphylococcus, but you would need to look at it under a microscope (they are round balls), and probably do a gram stain (I think they are gram positive), and you still wouldn't be sure exactly what it is. To determine the species exactly, you would need to do a genetic analysis, but knowing the exact species of bacteria that grew isn't that important to your results, unless you are interested in whether the product kills a specific species.
Fuzz or hair usually indicates mold or a fungus of some kind, but without seeing it, my money's on staph - it's so common, it's everywhere.
Reply:If you have just a generic agar plate, there is almost no way to tell what it is just by looking. Some species are more common than others, of course, and some hang out in some places more than others. But that would pretty much be total guesswork.
Generally how someone would determine what specific species a particular culture was would be to look at it under a microscope or try growing it on a number of other plates that would narrow down your choices on the basis of biochemistry. Either of which is probably more work than you're interested in doing.
I would suggest just getting colony population counts and stating for your project what common bacteria can be found wherever it was you got your samples from and wherever it is you live. There are literally hundreds of possibilities in all likelihood!
Reply:Try this:
http://science.jrank.org/pages/711/Bacte...
Reply:That's not enough info to even make a guess... Here's something simple you can do to narrow it down A LITTLE.. Place a drop of 3% Hydrogen peroxide on one of your colonies, if it bubbles that means it's catalase positive, if there are no bubbles then it's negative. A gram stain and some other simple biochem agars would be very helpful..
I assume you're not using any kind of blood agar, if you are then you will want to remove a colony aeseptically from that to a glass slide so you don't get a false positive..
Reply:You took some cultures. So I think you've got the stuff to determinate the cultures. Agarplates, microscope and Gram staining stuff ready? Here we go!
Small white and yellow strains:
Make a slide of the strain you want to know (count all the strains, as one species, if they look the same) and follow the Gram staining protocol.
*If it's a Gram negative cocci (O-form, pink), I dunno what to do.
*If it's a Gram positive cocci (O-form, purple), graft the strain to a new plate and put some bacitracine or furazolidone on it (sterile!)
%26gt;%26gt;
*If the strain is sensitive to furazolidone and not to bacitracine, and it can make H2O and O2 (bubbles!) out of H2O2 (hydrogenperoxide? Used to colour you hair...), it's a staphylococus species
*If the strain is sensitive to bacitracine and not to furazolidone, and it can make H2O and O2 out of H2O2, it's a micrococcus species
*If the strain can't make H2O and O2 out of H2O2, it's a streptococcus species
****
*If it's a Gram positive rod ( | -form, purple), and a sporeformer it's a Bacillus species
*If it's a Gram positive rod ( | -form, purple), and NOT a sporeformer I dunno what it's
*If it's a Gram negative rod ( | -form, pink), you may cal it a member of the Entrobacteriaceae-family - you should use some more tests to get the name of the species
*If it's a Gram positive rod ( Y -form, purple), incubate at 37 and 55 degrees
%26gt;thermophiler Actinomycet only lives at 55 degrees
%26gt;if it's lives at 37 and 55 degrees it's ... (there is a name for it, but I dunno at the moment)
Other species are unidentified
We did our 1st set of testing the other day (Tuesday) and today we examined it.
The bacteria or unknown growing bacteria of culture we took
it looks like
lots of small white fuzzy little colonies of bacteria or I have no idea what.
I have been trying to figure out what the bacteria is by looking at it.
Anyone have any ideas what the bacterica or culture could be. I have been looking on line fore a few hours nows and have gotten not so far.
So I would like peoples ideas on what it could be or if you know a good site I can look at!
Thanks!
Bacteria help!!?
Identifying bacterial species is a nearly impossible task unless you can narrow it down based on the source. If it came from your skin it is most likely Staphylococcus, but you would need to look at it under a microscope (they are round balls), and probably do a gram stain (I think they are gram positive), and you still wouldn't be sure exactly what it is. To determine the species exactly, you would need to do a genetic analysis, but knowing the exact species of bacteria that grew isn't that important to your results, unless you are interested in whether the product kills a specific species.
Fuzz or hair usually indicates mold or a fungus of some kind, but without seeing it, my money's on staph - it's so common, it's everywhere.
Reply:If you have just a generic agar plate, there is almost no way to tell what it is just by looking. Some species are more common than others, of course, and some hang out in some places more than others. But that would pretty much be total guesswork.
Generally how someone would determine what specific species a particular culture was would be to look at it under a microscope or try growing it on a number of other plates that would narrow down your choices on the basis of biochemistry. Either of which is probably more work than you're interested in doing.
I would suggest just getting colony population counts and stating for your project what common bacteria can be found wherever it was you got your samples from and wherever it is you live. There are literally hundreds of possibilities in all likelihood!
Reply:Try this:
http://science.jrank.org/pages/711/Bacte...
Reply:That's not enough info to even make a guess... Here's something simple you can do to narrow it down A LITTLE.. Place a drop of 3% Hydrogen peroxide on one of your colonies, if it bubbles that means it's catalase positive, if there are no bubbles then it's negative. A gram stain and some other simple biochem agars would be very helpful..
I assume you're not using any kind of blood agar, if you are then you will want to remove a colony aeseptically from that to a glass slide so you don't get a false positive..
Reply:You took some cultures. So I think you've got the stuff to determinate the cultures. Agarplates, microscope and Gram staining stuff ready? Here we go!
Small white and yellow strains:
Make a slide of the strain you want to know (count all the strains, as one species, if they look the same) and follow the Gram staining protocol.
*If it's a Gram negative cocci (O-form, pink), I dunno what to do.
*If it's a Gram positive cocci (O-form, purple), graft the strain to a new plate and put some bacitracine or furazolidone on it (sterile!)
%26gt;%26gt;
*If the strain is sensitive to furazolidone and not to bacitracine, and it can make H2O and O2 (bubbles!) out of H2O2 (hydrogenperoxide? Used to colour you hair...), it's a staphylococus species
*If the strain is sensitive to bacitracine and not to furazolidone, and it can make H2O and O2 out of H2O2, it's a micrococcus species
*If the strain can't make H2O and O2 out of H2O2, it's a streptococcus species
****
*If it's a Gram positive rod ( | -form, purple), and a sporeformer it's a Bacillus species
*If it's a Gram positive rod ( | -form, purple), and NOT a sporeformer I dunno what it's
*If it's a Gram negative rod ( | -form, pink), you may cal it a member of the Entrobacteriaceae-family - you should use some more tests to get the name of the species
*If it's a Gram positive rod ( Y -form, purple), incubate at 37 and 55 degrees
%26gt;thermophiler Actinomycet only lives at 55 degrees
%26gt;if it's lives at 37 and 55 degrees it's ... (there is a name for it, but I dunno at the moment)
Other species are unidentified
Agar/Bacteria?
I'm stumped on the first question of my bacteria lab...It says:
What was the purpose of this control? Did bacteria develop on it? Can you propose a hypothesis to explain this?
What we did was put 3 samples of bacteria into 3 quadrants of a petri dish. We left one quadrant clean (only the agar in it) for our control. We observed it every 2 days. The 3 samples became foggy and visible bacteria could be seen. The third didn't develop any bacteria, but became foggy. Would that be considered bacteria on the control? Because of the agar? Would the purpose of the control be to show what type of bacteria forms on the agar? How would I form a hypothesis?
Agar/Bacteria?
The control show's no growth, so long as your technique was aseptic, (that you didn't contaminate it). If they became foggy, that would most likely be condensation. your supposed to put the plates lid side down to prevent that.
Reply:Bacteria did not develop on your control plate. When you say became foggy I think you are referring to the condensation that formed on the lid of the petri dish. This is because of the water content of the agar, not because of bacteria.
The control shows that your aseptic technique was good. I suspect you plated a blank sample (no bacteria) on your control plate. Had it developed bacteria, it would indicate that either your equipment or your media was contaminated.
Reply:Do you understand what a control is, what it's for?
What did you expect when you plated the bacteria onto the first three quadrants?
What did you expect when you did NOT plate bacteria onto the last quadrant?
What was the purpose of this control? Did bacteria develop on it? Can you propose a hypothesis to explain this?
What we did was put 3 samples of bacteria into 3 quadrants of a petri dish. We left one quadrant clean (only the agar in it) for our control. We observed it every 2 days. The 3 samples became foggy and visible bacteria could be seen. The third didn't develop any bacteria, but became foggy. Would that be considered bacteria on the control? Because of the agar? Would the purpose of the control be to show what type of bacteria forms on the agar? How would I form a hypothesis?
Agar/Bacteria?
The control show's no growth, so long as your technique was aseptic, (that you didn't contaminate it). If they became foggy, that would most likely be condensation. your supposed to put the plates lid side down to prevent that.
Reply:Bacteria did not develop on your control plate. When you say became foggy I think you are referring to the condensation that formed on the lid of the petri dish. This is because of the water content of the agar, not because of bacteria.
The control shows that your aseptic technique was good. I suspect you plated a blank sample (no bacteria) on your control plate. Had it developed bacteria, it would indicate that either your equipment or your media was contaminated.
Reply:Do you understand what a control is, what it's for?
What did you expect when you plated the bacteria onto the first three quadrants?
What did you expect when you did NOT plate bacteria onto the last quadrant?
Bacteria are often used in food production. Are they ever the whole food product, itself?
I know there are ways to grow %26amp; harvest pure bacterial spores, which could doubtless be activated temporarily enough to be living bacteria, so that you can have a pile of living bacteria without necessarily having to have them "in" anything for them to eat. I also know that living bacteria (bacteria that are living when you eat them) are present in and added to yogurt and certain other foods on purpose, but bacteria -added- to other substances is not what I'm talking about. Whether active or dormant, is bacteria ever used as a food in and of itself?
The concept seems gross, but if it can be viable, it would be an interesting concept for an "emergency foodsource" because one thing we'll -always- be able to grow, even when crops and livestock fail - will be bacteria.
Bacteria are often used in food production. Are they ever the whole food product, itself?
Probably not unless it was perfected enough but unless you count fungus like mushrooms and some types of molds probably not unless the plant or animal turned into a bacteria over time as well.
street fighting
The concept seems gross, but if it can be viable, it would be an interesting concept for an "emergency foodsource" because one thing we'll -always- be able to grow, even when crops and livestock fail - will be bacteria.
Bacteria are often used in food production. Are they ever the whole food product, itself?
Probably not unless it was perfected enough but unless you count fungus like mushrooms and some types of molds probably not unless the plant or animal turned into a bacteria over time as well.
street fighting
How long does bacteria exist in agar?
When you mix agar and bacteria in a petri dish bacteria forms. How long does the bacteria last? After you leave the bacteria in the dish overnight, you are able to see the bacteria. How long will you be able to see the bacteria for? Does the bacteria disappear? If you would freeze the dish in the freezer, will the bacteria be maintained in the dish, still visible?
Keep in mind I'm only in grade 9 so keep it simple
How long does bacteria exist in agar?
Bacteria go through several phases: Lag phase, growth phase, stationary phase, and death phase.
Death phase is when the bacteria begin to die and it occurs when bacteria run out of nutrients (i.e. all the nutrients in the agar have been used up). You will be able to see the bacteria for as long as there are still nutrients present to sustain them. The bacteria do not disappear, they lyse (to put it in crude terms, they blow up). Some bacteria produce endospores, which are structures that can be subject to extreme conditions but still survive. These can give rise to more bacteria if you give them nutrients and a favorable environment.
If you freeze bacteria, they will form spores if they can but otherwise they will probably die depending on what kind of bacteria you're using. You can genetically modify bacteria in many ways to make them more cold resistant. There are also bacteria that naturally survive in extreme heat or cold. You will likely still see the colonies but the bacteria may be dead.
Reply:exactly! first poster is right on.... after all the starches/nutrients are used up (eaten by the bacteria).... the colonies will begin to die off... they will still be visible on that agar plate or tube, but they will be dead.
The cold tolerant bacteria that the first poster mentioned are called "psycrophiles" in microbiology.. and any bacteria that can live in Cold, or hot conditions and thrive are collectively known as "extremophiles". Hot loving bacteria are called "thermophiles"
There are other types as well... in case you were interested.
Iron-loving bacteria are known as "siderophores" and salt loving bacteria are called "halophiles".
Reply:If your goal is to keep the plates for a long time and still be able to see the colonies, it's pretty simple.
Once the colonies are at a size you can easily see, seal the edges of the petri dish closed so the agar inside won't dry up. (Parafilm or some stretchy tape works best, but any kind of tape will work if you do a good job %26amp; ensure there are no gaps.)
Then put the plate in the refrigerator (not the freezer). I'm not sure how long it will last like that, but I'd guess at least a year. As the other posters said, many of the bacteria may die, but you'll still be able to see the colonies.
Remember to keep the plate upside down while it's in the fridge. Otherwise, drops of condensation may form on the lid and drop down onto the agar surface. That will mess up the colonies.
Keep in mind I'm only in grade 9 so keep it simple
How long does bacteria exist in agar?
Bacteria go through several phases: Lag phase, growth phase, stationary phase, and death phase.
Death phase is when the bacteria begin to die and it occurs when bacteria run out of nutrients (i.e. all the nutrients in the agar have been used up). You will be able to see the bacteria for as long as there are still nutrients present to sustain them. The bacteria do not disappear, they lyse (to put it in crude terms, they blow up). Some bacteria produce endospores, which are structures that can be subject to extreme conditions but still survive. These can give rise to more bacteria if you give them nutrients and a favorable environment.
If you freeze bacteria, they will form spores if they can but otherwise they will probably die depending on what kind of bacteria you're using. You can genetically modify bacteria in many ways to make them more cold resistant. There are also bacteria that naturally survive in extreme heat or cold. You will likely still see the colonies but the bacteria may be dead.
Reply:exactly! first poster is right on.... after all the starches/nutrients are used up (eaten by the bacteria).... the colonies will begin to die off... they will still be visible on that agar plate or tube, but they will be dead.
The cold tolerant bacteria that the first poster mentioned are called "psycrophiles" in microbiology.. and any bacteria that can live in Cold, or hot conditions and thrive are collectively known as "extremophiles". Hot loving bacteria are called "thermophiles"
There are other types as well... in case you were interested.
Iron-loving bacteria are known as "siderophores" and salt loving bacteria are called "halophiles".
Reply:If your goal is to keep the plates for a long time and still be able to see the colonies, it's pretty simple.
Once the colonies are at a size you can easily see, seal the edges of the petri dish closed so the agar inside won't dry up. (Parafilm or some stretchy tape works best, but any kind of tape will work if you do a good job %26amp; ensure there are no gaps.)
Then put the plate in the refrigerator (not the freezer). I'm not sure how long it will last like that, but I'd guess at least a year. As the other posters said, many of the bacteria may die, but you'll still be able to see the colonies.
Remember to keep the plate upside down while it's in the fridge. Otherwise, drops of condensation may form on the lid and drop down onto the agar surface. That will mess up the colonies.
Bacteria . . .?
Why is sterilization repeated for each step of the culture method?
Bacteria . . .?
It is absolutely to avoid contamination. For example, if you are trying to amplify a plasmid that you constructed by PCR, then you do not want other unwanted bacteria (that you cannot determine which bacteria have the plasmid or not) on your plate or in your LB. You do not want your hard work going down the drain becuase of some contamination that could have been prevented.
good luck.
Reply:to avoid contamination.
Reply:To not let germs get in.
Reply:to ensure its effectiveness....
Bacteria . . .?
It is absolutely to avoid contamination. For example, if you are trying to amplify a plasmid that you constructed by PCR, then you do not want other unwanted bacteria (that you cannot determine which bacteria have the plasmid or not) on your plate or in your LB. You do not want your hard work going down the drain becuase of some contamination that could have been prevented.
good luck.
Reply:to avoid contamination.
Reply:To not let germs get in.
Reply:to ensure its effectiveness....
Bacteria...?
Can I find bacteriophages on my hands? How?
Thanks!!!
Bacteria...?
bacteriophages are VIRUSES that infect bacteria. They don't infect your own cells. But, you do have bacteria on your body and on your skin, so they could be there.
Thanks!!!
Bacteria...?
bacteriophages are VIRUSES that infect bacteria. They don't infect your own cells. But, you do have bacteria on your body and on your skin, so they could be there.
Bacteria?????
how does metal stop the growthof bacteria???
Bacteria?????
Not all metals stop bacterian growth....there are metals that bacteria thrieves on, like iron....like the bacteria eating up the wreck of Titanic...Some metals like silver are known to inhibit bacterian growth....hope someone can tell you more about how this is done...
Reply:Metals act as disinfectants to denature proteins. (That's why they put AgNO3 on newborns' eyes, to prevent the growth of N. gonorrhea, etc)
grappling
Bacteria?????
Not all metals stop bacterian growth....there are metals that bacteria thrieves on, like iron....like the bacteria eating up the wreck of Titanic...Some metals like silver are known to inhibit bacterian growth....hope someone can tell you more about how this is done...
Reply:Metals act as disinfectants to denature proteins. (That's why they put AgNO3 on newborns' eyes, to prevent the growth of N. gonorrhea, etc)
grappling
Bacteria...?
What nutrients are present in LB agar that most bacteria need? What ingredients are used for that purpose?
Could you give me your sources?
Thanks a million!
Bacteria...?
tryptone, a peptide, provides a source of protein; Vitamins and certain trace elements are provided by yeast extract. Sodium ions for transport and osmotic balance are provided by sodium chloride.
Could you give me your sources?
Thanks a million!
Bacteria...?
tryptone, a peptide, provides a source of protein; Vitamins and certain trace elements are provided by yeast extract. Sodium ions for transport and osmotic balance are provided by sodium chloride.
Bacteria ???????????????
please , do you can explain how we can overcome the mutation in the bacteria ? please in chemical details .
Bacteria ???????????????
is that even possible? Mutations cause things to evolve...can we stop it? maybe if the dna copying never made mistakes.
Reply:Keep it in a uniform environment with no stresses at all and improve the replicating polymerase so that it never made a single mistake.
Bacteria ???????????????
is that even possible? Mutations cause things to evolve...can we stop it? maybe if the dna copying never made mistakes.
Reply:Keep it in a uniform environment with no stresses at all and improve the replicating polymerase so that it never made a single mistake.
Bacteria...?
How do bacteria create resistance to antibiotics and other chemicals? What happens really inside of them that makes them resistant?
Thanks a million!
Bacteria...?
Antibiotic resistance is a consequence of evolution by natural selection. Those bacteria which have a mutation allowing them to survive will live on to reproduce. They will then pass this trait to their offspring.
There are four main ways resistance manifests within the bacteria.
1. Drug inactivation or modification: e.g. enzymatic deactivation of Penicillin G in some penicillin-resistant bacteria through the production of Beta-lactamases.
2. Alteration of the binding target site of penicillins—in MRSA and other penicillin-resistant bacteria.
3. Alteration of metabolic pathway: e.g. some sulfa-resistant bacteria do not require para-aminobenzoic acid (PABA), an important precursor for the synthesis of folic acid and nucleic acids in bacteria inhibited by sulfonamides. Instead they utilize preformed folic acid.
4. Reduced drug accumulation: by decreasing drug’s ability to pass through the cell’s surface.
The bacteria’s DNA changes and allows them to survive. Sometimes these traits happen in plasmids which are little pieces of DNA that are outside the nucleus. Plasmids can also pass from one cell to another without reproduction or cell division.
Reply:a byproduct of some unrelated biochemical process that you're carrying out naturally-you don't want to be killed by that. So you have a resistance mechasim built in. And somehow, that resistance gene or genes came out of you and moved to another bacterium that isn't making the antibiotic, but now resists the antibiotic.
Because these genes are transferable, and they eventually got transferred to other bacteria. In the process, mutations could occur, adaptations could occur. But the basic mechanism, in fact we find in many of the producing organsims.
The Darwinian idea is that if they make that change and it helps them, then that change becomes more permanent. So a mutation to a gene that results in a resistance to an antibiotic like pennicillin in certain bacteria could be a mutation in the target. And those bacteria survive, and their progeny now carry that mutation.
might have never made it in normal times-now, if they give the bacterium the ability to resist an antibiotic, they are there and they are there to stay.
Reply:it happens when bacteria sensitive to any type of antiobitic grow in an isotonic medium.
Thanks a million!
Bacteria...?
Antibiotic resistance is a consequence of evolution by natural selection. Those bacteria which have a mutation allowing them to survive will live on to reproduce. They will then pass this trait to their offspring.
There are four main ways resistance manifests within the bacteria.
1. Drug inactivation or modification: e.g. enzymatic deactivation of Penicillin G in some penicillin-resistant bacteria through the production of Beta-lactamases.
2. Alteration of the binding target site of penicillins—in MRSA and other penicillin-resistant bacteria.
3. Alteration of metabolic pathway: e.g. some sulfa-resistant bacteria do not require para-aminobenzoic acid (PABA), an important precursor for the synthesis of folic acid and nucleic acids in bacteria inhibited by sulfonamides. Instead they utilize preformed folic acid.
4. Reduced drug accumulation: by decreasing drug’s ability to pass through the cell’s surface.
The bacteria’s DNA changes and allows them to survive. Sometimes these traits happen in plasmids which are little pieces of DNA that are outside the nucleus. Plasmids can also pass from one cell to another without reproduction or cell division.
Reply:a byproduct of some unrelated biochemical process that you're carrying out naturally-you don't want to be killed by that. So you have a resistance mechasim built in. And somehow, that resistance gene or genes came out of you and moved to another bacterium that isn't making the antibiotic, but now resists the antibiotic.
Because these genes are transferable, and they eventually got transferred to other bacteria. In the process, mutations could occur, adaptations could occur. But the basic mechanism, in fact we find in many of the producing organsims.
The Darwinian idea is that if they make that change and it helps them, then that change becomes more permanent. So a mutation to a gene that results in a resistance to an antibiotic like pennicillin in certain bacteria could be a mutation in the target. And those bacteria survive, and their progeny now carry that mutation.
might have never made it in normal times-now, if they give the bacterium the ability to resist an antibiotic, they are there and they are there to stay.
Reply:it happens when bacteria sensitive to any type of antiobitic grow in an isotonic medium.
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