In human gene therapy, a genetically modified virus (a.k.a. a viral vector) can alter the genetic variation of a cell, but not all viral vectors do.
The process often begins with the delivery of or creation of a segment of viral double stranded DNA (containing the gene you want to introduce). Then typically an enzyme known as an integrase cuts the ends of the segment of viral DNA and also cuts open the cell's DNA. Then the viral DNA is integrated/ inserted into the cell's DNA. The connecting ends are ligated together and adjusted so that the nucleotide base pairs match up.
This in the future may affect the gene pool for instance if the viral DNA (your gene) was inserted in the middle of another gene or important regulatory sequence of the cell DNA, and this alteration may be passed on into offspring and become present in the gene pool, which could have bad effects.
The effects on the gene pool really depends on what the virus ends up doing. For example, it may fix the function of a damaged gene which is the goal, and allow for a working gene to be in the gene pool, which would be good. The problem with gene therapy is that it's difficult to predict 100% what the virus will do every time it is given to a patient.
But it's very important to consider that it will only affect the gene pool if the virus is able to enter and alter germ cells (reproductive cells). If the virus, enters somatic cells (regular body cells) this will not be passed on to future generations. So viruses can be designed to avoid germ cells and avoid this gene pool issue. Also, some viral vectors use viruses that do not integrate their DNA, the cells just express the viral DNA (create the desired protein from it) and over time the viral DNA is degraded/ lost which wouldn't pose this threat.
This is long, but I hope it helped!
Well, ask yourself, "Do I try hard enough?" "Was it the best I could do?" And well if the answer is yes, then you have nothing to stress out about too much. Maybe talk to your teacher and ask for extra credit. Get tutoring. Talk to a guidance counselor. If none of that helps, well then you're just not the best at the subject, but just try your best. In the future, you won't even remember about all those grades! Coming from a 6th grader, the beginning of the year was super hard. I'm not the best at math, but I'm very good at Language Arts. Everyone has their own weaknesses and strengths. Don't worry about it.
Answer:
Among the oldest methods of preservation are drying, refrigeration, and fermentation. Modern methods include canning, pasteurization, freezing, irradiation, and the addition of chemicals.
Explanation:
Answer:
1. Surface (substratum) is preconditioned by environment molecules.
4. Microbes attach and detach from the preconditioned surface.
2.Quorum sensing and the establishment of the extracellular matrix commences as microbes attach more stably.
3. Biofilm matures and some microorganisms escape to the plank-tonic state.
Explanation:
Biofilm is a process in which microorganism irreversibly attach and grow on the surface to produce extra cellular polymers that facilitate formation of matrix. The biofilm process takes three days for the formation after which thickness of plaque increases. There are 4 main steps in biofilm formation. Surface is preconditioned by environment molecules. The microbes attach the preconditioned surface. Establishment of extra cellular matrix and finally biofilm matures.
