What is Reverse: Definition and 309 Discussions

A reverse transcriptase (RT) is an enzyme used to generate complementary DNA (cDNA) from an RNA template, a process termed reverse transcription. Reverse transcriptases are used by certain viruses such as HIV and hepatitis B to replicate their genomes, by retrotransposon mobile genetic elements to proliferate within the host genome, and by eukaryotic cells to extend the telomeres at the ends of their linear chromosomes. Contrary to a widely held belief, the process does not violate the flows of genetic information as described by the classical central dogma, as transfers of information from RNA to DNA are explicitly held possible.Retroviral RT has three sequential biochemical activities: RNA-dependent DNA polymerase activity, ribonuclease H (RNase H), and DNA-dependent DNA polymerase activity. Collectively, these activities enable the enzyme to convert single-stranded RNA into double-stranded cDNA. In retroviruses and retrotransposons, this cDNA can then integrate into the host genome, from which new RNA copies can be made via host-cell transcription. The same sequence of reactions is widely used in the laboratory to convert RNA to DNA for use in molecular cloning, RNA sequencing, polymerase chain reaction (PCR), or genome analysis.

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  1. Andre

    Concealing Landmarks for google reverse image search

    So we have been struggling to defeat the google image searcher. This seems to work While we see what it is, google didn't have any idea. I made this with googles Picasa-3. It's very simple with a few clicks, I selected pencil drawing and then some other tricks, changing colors and...
  2. A

    Relativity: can two observers see two events in reverse?

    Homework Statement S' moves at velocity 0.6c with respect to S, and x=x'=0 at t=t'=0. Two events are recorded. In S, event 1 occurs at x=0 and t=0, and event 2 occurs at x=3000m and t=4μs. At what times does S' say the events happened? Does S' see the events in reverse order from S? The...
  3. B

    (Reverse) Schottky Diode Question

    Is a reverse Schottky diode possible? I understand the basics of the Schotkky barrier/rectifier commonly achieved by a metal/semiconductor interface. Recently, it was suggested to me that a "reverse" Schottky junction is possible if the metal is placed against a fully depleted, high...
  4. D

    How would I reverse this equation?

    52x95^0 + 79x95^1 + 0x95^2 + 66x95^3 = 56594307. Let's say I'm given 56594307 and 95. How would I find out the numbers 52,79,0 and 66? Basically if you read the first section of this link 9.4.1 Text Blocking http://www.math.mtu.edu/mathlab/COURSES/holt/dnt/phi4 . html I...
  5. L

    Reverse Engineering Derivations - How?

    Homework Statement I have to reverse engineer a derivation in a paper and have no idea where to even start. The amount of terms are overwhelming and I can't imagine how the author even began. Homework Equations The following equations are known...
  6. T

    Reverse the order of integration?

    Homework Statement Reverse the order of integration? Original has it in the form of dy dx, 0<=x<=ln6, 1<=y<=e^x. I made it dx dy, with 1<=x<=e^y, 0<=y<=ln6 Is this right? Homework Equations The Attempt at a Solution
  7. D

    Why can't photons reverse annihilate ?

    Why can't photons "reverse annihilate"? If electron-positron pairs annihilate to product gamma radiation, why can't gamma photons spontaneously become a electron-positron pair?
  8. L

    Reverse Carnot - Refrigeration Cycle problem

    Hi guys, I have difficulties understanding the what I need to do in this problem. I have a ideal refrigeration cycle. first part is standard calculations, work of compressor and such. Results are Temperature range between -23 and 60 degrees C. Second part is the one that i do not understand. it...
  9. P

    Proving NFA accepts reverse string of DFA

    I have seen descriptions for an algorithm that can take a regular deterministic finite automata and create a non-deterministic finite automata that is guaranteed to generate the reverse of string accepted by the DFA. Does anyone know of a "formal" proof that shows this is true in all cases...
  10. I

    Infix to Reverse Polish notation

    I have to convert.. X=A+((B+C)*D)-E to reverse polish notation I think it's... BC+D*A+E- Is this correct?
  11. Y

    Finding your annuity, Finding your reverse annuity

    ~TLDR at the bottom~ Homework Statement The Big question: Variables Account 1: P=250 R=.005 N=12 T=46 Variables Account 2: A1=155123.83 R=.0025 N=12 T=15 Homework Equations Annuity Formula(Given): A=P[(1+(r/n))nt)-1] ______________ (r/n)...
  12. H

    Why photodiode is operated in reverse bias?

    why photodiode is operated in reverse bias?? can anyone please explain why photodiode is operated only in reverse bias?? can we operate it forward bias state also??
  13. S

    Reverse Saturation Current ,Is Formula

    Homework Statement I am work on VLSI study currently and I am having problem in the static power consumption. Homework Equations I have an equation here, I= Is [e^qv/kt - 1] and I just wish to know is there any formula for calculation the Is. The Attempt at a Solution
  14. G

    A Reverse Startup Oscillation?

    A "Reverse" Startup Oscillation? I have a very flexible plastic ruler 61cm long, 5cm wide, and .2cm thick. I hold it by one end, with the "width" vertical, and sight along the ruler "aiming" at any vertical edge (like a door jamb). When I quickly move the ruler to the left a couple of...
  15. R

    Why can Hawking Radiation not work in reverse?

    I understand that to obey conservation that the black hole must lose energy and mass and the surrounding space must gain an equal amount of energy and mass. Then why can the antiparticle not be emitted from the black hole, adding negative energy and mass to the surrounding space, and the...
  16. I

    Comp Sci Reverse words of a string C++

    Write a program to reverse words of a string individually, for example if you enter: I love C++, it should display I evol ++C They've given the solution in my textbook but I don't quite understand the logic behind it. void main( ) { int l, i, k = 0 ; char str[80], word[80] ...
  17. L

    BJT in the reverse active region and beta

    For the BJT in the reverse active region, why shouldn't you dope the emitter and collector almost equally, even though it will increase beta_r? Also, what are some ways you can increase beta_r (in reverse active) or beta_f (in forward active)?
  18. S

    Reverse Piezoelec effect queries

    How accurately can reverse piezoelectric effect be controlled? Can I say if I apply so and so voltages across it i can expand it to so and so distance and statically hold it in that position for some time(Small timings around 10 millisecs)? If no any other mechanism that can be employed?
  19. O

    AC Motor Reversing: Is It Possible?

    Say I have an AC motor with 100 ft*lbs torque, and I run it against a load of 200 ft*lbs torque so that the motor spins in the opposite direction of the power it is providing. Is this possible, and if so can this condition be sustained over a period of time without damaging the motor?
  20. N

    Calculating Reverse Bias Voltage for Alpha Particle Detection

    Hi all, me again! :rolleyes: I'm trying to calculate the current created when an alpha particle strikes a silicon p-n detector, but I'm getting some strange numbers, so I was wondering if I was doing something fundamentally wrong... My problems start when I try to calculate the reverse...
  21. H

    What to use when reverse chain rule doesnt work?

    Hi there, My equation to solve is (xy+(x^2))dx + (-1)dy=0 For method of exact solutions, the partials are not equal to each other so I cannot use exact solutions (reverse chain rule) I don't know how to solve this
  22. S

    Can the Modulus Rule Be Reversed?

    Homework Statement Give an example to show that the modulus rule cannot be reversed. Hence give an example of a divergent sequence (a_{n}) such that (|a_{n}|) is convergent.Homework Equations The modulus rule is; "Let a_{n} be a convergent sequence. (|a_{n}|) is convergent, then lim|a_{n}|...
  23. T

    Understanding how to reverse the integration order

    Hello, I am talking about double integrals. I have seen many examples of how to reverse the integration order when current order is too difficult to calculate. But I still don't fully understand how to do it. I would like you to help me understanding this. Suppose the integral: ∫∫f(x,y)...
  24. M

    Will an induction cooker work in reverse if a hot pan is place on the coil?

    I was wondering whether an induction hob cooker would work in reverse if a hot pan is placed on the coil - so would this generate a current? I would assume not as the heat induction pan wouldn't be able to create a magnetic field in the coil?
  25. A

    Comp Sci Understanding Java Recursive Array Reversal

    supposed to reverse an array of strings recursively. this is in a class that has an array object. i came up with what's below. but it reverses the array in a weird order. the array is a 5 element array, the elements are {hello, how, are you, ?}. i passed in the object and after printed out...
  26. A

    Reverse saturable absorption. Rate equations.

    Hello to all. Nice forum. Really like it. I hopee you'll can help me. The rate equaition in the case of reverse saturable absorber, with a long-lived strongly absorbing excited state (T0) which is rapidly populated from a ground state (S0), are given as: \frac{dS_{0}}{dt} = - \sigma_{01} S_{0}...
  27. E

    AC induction motor reverse 3 phase

    What happens if an big AC induction motor is running with full load an your suddenly reverse the 3 phase?
  28. Philosophaie

    Trig function of arc trig functions and the reverse

    I know the sin(arccos(x)) = (1-x^2)^0.5 I was wondering what some of the others are: cos(arcsin(X)) tan(arcsin(X)) tan(arccos(x)) sin(arctan(x)) cos(arctan(x)) also the reverse: arcsin(cos(x)) arcsin(tan(X)) arccos(Sin(X)) arccos(tan(X)) arctan(sin(X)) arctan(cos(X))
  29. J

    What is the purpose and design of wire mesh on radar antennas?

    Hi, I havn't posted for quite some time yet I have been reading through from time to time. I would like to ask about Radars. I wish to be able to look at a radar antena and be able to say as possible. Such as frequency ranges from the antenna size etc... Does the size of the 'Ball' in which...
  30. O

    Is it possible for the arrow of time to be observed in reverse?

    I know that in general the arrow of time does not itself reverse but is it possible for there to exist 'observers' in our universe that see its progression from, what we think as, finish to start? I just read http://arxiv.org/pdf/hep-th/0611088v3" by Brett McInnes so I understand why the...
  31. L

    Can a Cavity Magnetron Be Used in Reverse to Generate Resonant Frequencies?

    Could a cavity magnetron be done in reverse in a way so that the em waves would interact with the magnetic field and give electrons energy to jump from a cathode to an anode and would any resonant frequencies be involved? I've read some where that this is why metal articles should not be put...
  32. G

    Creating a reverse image search platform

    Hi all, Was told by an engineer at a tech startup to inquire here for anyone interested in discussing/solving/working on this problem. Basically, I am looking to crawl and index all images on a certain part of the web (yet undefined which part) and to be able to run a reverse image search...
  33. P

    Sample Exam Fourier Series & reverse engineering the question

    Homework Statement Hey, This is a question from a sample exam we are given for our engineering maths exam. Firstly given that the Fourier series contains only "sin(x)" doesn't this mean that it is an "odd" function? Can the period be calculated from the given function easily? Secondly is...
  34. M

    What is Meant by By Symmetry in the Reverse Triangle Inequality Proof?

    Homework Statement I'm reading the proof for the reverse triangle inequality, but I don't understand what is meant by "by symmetry" Homework Equations The Attempt at a Solution (X,d) is a metric space prove: |d(x,y) - d(x,z)| <= d(z,y) The triangle inequality d(x,y) <=...
  35. J

    Reverse Biasing a Voltage Regulator

    Hello All, Simple question here. I have a microcontroller development board that plugs into the wall and has a garden variety LM7805 type 5V regulator on the board for powering the microcontroller and other peripherals. But also on this board is a header that allows the 5V from the board to...
  36. W

    Any good reverse image search engine out there?

    I am looking for something on the lines of this - http://www.tineye.com/ . i.e a site where one uploads an image and it gives back similar images from other websites. (note - I am not asking for face recognition or similar thing , that I guess would be a big demand . I just wanted to find...
  37. J

    Equilibrium vs. Reverse Bias

    In a PN junction under reverse bias, a small bit of current exists due to the movement of minority carriers. Under equilbrium, no current passes through. Am I right in thinking that the movement of minority carriers under equilibrium is canceled by the little bit of majority carriers that passes...
  38. C

    Is a Reverse Quantum Computer Possible?

    In a standard quantum computer, the computing machinery is kept in a superposition of states, with each state doing the computation on different data. It's like having the superposition of a bunch of cats in a box with each cat doing a calculation on different data. The more complex the cat...
  39. R

    Reverse current without reversing voltage?

    I was studying First and Fourth quadrant choppers and that got me thinking. Can the chopper run in the first and second quadrants meaning always Positive voltage across the load and Positive and negative load current. My reasoning makes me think that it is not possible. Any help?
  40. J

    The Conundrum of Duplicating Atoms in Time Travel

    Let’s say someone travels one year in the past to change their own lives coarse, maybe lotto numbers or something else. Doesn’t matter if time travel is possible or not, this is just a thought experiment.? The problem I see is that somehow you’ll have to duplicate the nuclei that make up your...
  41. L

    Forward vs Reverse Reaction (both endo/exo thermic)

    Can both the forward and reverse reaction be endothermic or exothermic? Or must they ALWAYS be inverse one another? Thanks
  42. L

    How do i do this question? I get the reverse

    Homework Statement find dy/dx yx2+ xy2=7 Homework Equations The Attempt at a Solution xy(x+y)=7 2xy=(x+y) (x+y) = 7 2xy + x2+2xy +y2=0 2xy + dx/dy(x2+2xy+y2)=0 2xy +x2+dy/dx 2xy + dy/dx y2 dy/dx = (-2xy-x2)/(2xy + y2) The answer is actually (-y2+2xy)/(x2+2xy) Can...
  43. S

    Reverse polarity in torque motor

    I need to control a torque motor using variable voltage. I also need to have it rotate in reverse. Basically what I need it to do is start at +24VDC at one end, hit 0VDC in the middle, then finish up at -24VDC. Is there a potentiometer that can reverse polarity at the halfway point or do I...
  44. PainterGuy

    There will be current when diode is reverse biased

    hi everyone, please see fig 42.25 a and b on this google doc:--- https://docs.google.com/viewer?a=v&pid=explorer&chrome=true&srcid=0B_XrsbDdR9NEMDNhNzVhZTktNzZhMy00ZGI0LWEyZGYtM2RmMTA3MDQxMTlm&hl=en&authkey=CKP-7OsD i can understand the fig 42.25a and why the current flows. but i have...
  45. S

    How can I write complex equations using Reverse Polish notation?

    So I need some help with RPN, I checked the wiki page but I still don't quite get it. Like I get simple multiplications, aditions etc. But how would you for example write:
  46. J

    How to reverse the action of a small 12V DC MOtor

    Hey Guys ! I am working on a personal project, and I was hoping you could give me some help and advices. I am looking for a tool/device that would reverse the action of a small 12V DC motor (make it operate clockwise and then counter-clockwise for example). And I was also wondering what kind...
  47. M

    Current in forward and reverse bias

    What are the equations for current due to hole flow and current due to electron flow, respectively? I can't seem to find those formulas anywhere. Are they the same as the saturation current due to hole flow and electron flow?
  48. H

    Level shifting with a reverse biased small signal diode

    I have found a circuit that uses a BAS16 small signal diode to level shift a 5V (or 3.3V) TTL signal down to a 1.8V TTL signal. The cathode of the diode is on the high voltage side and the anode is on the low voltage side, so it looks like it is backwards compared to the direction of current...
  49. J

    Java Reversing a Sentence with Java - No Loops

    We are asked to reverse a sentence , example: I am going. ==> .going am I Attempt: import java.util.Scanner; public class Assign2 { public static void main (String [] args) { String line= new StringBuffer().reverse().toString(); String line2 = new...
  50. S

    What does reverse polarity in a DNA molecule mean?

    Ok I can see the 5 end is negative, is the 3 end positive due to OH. So in other strand this goes other way round. Is this what they mean when they say there is reverse polarity in a DNA molecule. Thanks!
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