What is Expression: Definition and 999 Discussions

Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product that enables it to produce end products, protein or non-coding RNA, and ultimately affect a phenotype, as the final effect. These products are often proteins, but in non-protein-coding genes such as transfer RNA (tRNA) and small nuclear RNA (snRNA), the product is a functional non-coding RNA. Gene expression is summarized in the central dogma of molecular biology first formulated by Francis Crick in 1958, further developed in his 1970 article, and expanded by the subsequent discoveries of reverse transcription and RNA replication.The process of gene expression is used by all known life—eukaryotes (including multicellular organisms), prokaryotes (bacteria and archaea), and utilized by viruses—to generate the macromolecular machinery for life.
In genetics, gene expression is the most fundamental level at which the genotype gives rise to the phenotype, i.e. observable trait. The genetic information stored in DNA represents the genotype, whereas the phenotype results from the "interpretation" of that information. Such phenotypes are often expressed by the synthesis of proteins that control the organism's structure and development, or that act as enzymes catalyzing specific metabolic pathways.
All steps in the gene expression process may be modulated (regulated), including the transcription, RNA splicing, translation, and post-translational modification of a protein. Regulation of gene expression gives control over the timing, location, and amount of a given gene product (protein or ncRNA) present in a cell and can have a profound effect on the cellular structure and function. Regulation of gene expression is the basis for cellular differentiation, development, morphogenesis and the versatility and adaptability of any organism. Gene regulation may therefore serve as a substrate for evolutionary change.

View More On Wikipedia.org
  1. Altagyam

    Write the Power Series expression for a given sequence

    Homework Statement http://sites.math.rutgers.edu/~ds965/temp.pdf (NUMBER 2)[/B]Homework Equations I do not understand the alternating part for the second problem and the recursive part for the first problem.The Attempt at a Solution The first answer I got was first by writing out the...
  2. adamaero

    Why does the trig expression just disappear?

    Homework Statement Homework Equations 3. Solution Then the equations from part (A) are used--but why does the converted trig (1-cos(etc)) go away? Does this have to do with the mean-squared bit?
  3. J

    Time period from potential energy expression

    Homework Statement Homework EquationsThe Attempt at a Solution U = 5x2 - 20x F = -dU/dx F = -10x + 20 The expression for force doesn't look like motion is SHM . How should I deal with this ?
  4. hugo_faurand

    B Calculate the expression of the antiderivative

    Hello everyone ! I've started to work on integral and I wonder if it's possible to calculate the expression of the antiderivative with the expression of the "integrand"1 rather than use a table with the function and its antiderivative. Thank you in advance ! 1( I'm french and I d'ont know the...
  5. Marcos Domingues

    Integrating an Expression with d(h³)/dt

    Homework Statement [/B] I have this expression: dV/dt = F0 - K*h^(1/2); it describes a variation in time of a fluid volume V in a cone-shaped tank of total volume H*pi*R²/3; By a trigonometric relation we get V = (pi*R²/3*H²)*h³; since tan a = H/R = h/r where: R = radius of the tank; H =...
  6. Richie Smash

    Derive an expression for the price of a pen in terms of p

    Homework Statement Hello there are two types of pens expensive and cheap. The ratio of the prices of the two is 3:7 The total cost for 30 of the cheaper pens and 10 of the expensive pens is $1568. I am asked to derive an expression for the cost of ONE of the expensive pens which i will...
  7. M

    (Boolean Algebra) Did I write this logic expression correctly?

    Homework Statement My solution, is this correct? This is what I came up with. Y=A+((A*B)+B+C'+(B+C'*D)+D) Is it safe to say that it is correct or did I make a mistake?
  8. binbagsss

    Component of Lie Derivative expression vector field

    1. Homework Statement Hi, I have done part a) by using the expression given for the lie derivative of a vector field and noting that if ##w## is a vector field then so is ##wf## and that was fine. In order to do part b) I need to use the expression given in the question but looking at a...
  9. I

    Different lengths of genes expressed

    I was wondering whether it can ever happen that only a certain "length" of the same gene gets expressed in different species? Or perhaps even within the same species? (Without it being a random mutation) Basically, can a part of a gene be expressed, and still have some functionality in the...
  10. Adgorn

    Need help with a trigonometric expression

    Homework Statement Just a simple problem, I need to take the expression##\frac 1 2 (sin(2x)+1)## and show it is equivalent to ##sin^2(x+\frac \pi 4)##, and I can't seem to manage to find the way to do so, so I would appreciate some insight. Homework Equations N/A The Attempt at a Solution...
  11. nothing909

    Expression for closed loop gain of differential amplifier

    Homework Statement The question is Derive an expression for the closed loop gain of the differential amplifier. I have solutions for these questions but the solution for this question is quite vague. Here is the solution: I understand part 1 and part 3, but part 2 I don't. So looking at...
  12. AbigailG

    Find an Expression for the Frequency - Pendulum

    Homework Statement [/B] A solid sphere of mass M and radius R is suspended from a thin rod. The sphere can swing back and forth at the bottom of the rod. Find an expression for the frequency of small angle oscillations.Homework Equations f = 1/2(pi) sqrt(MgR/I) I for a solid sphere 2/5MR^2The...
  13. G

    Proving the Equality of Two Complex Expressions Using Algebraic Manipulation

    Homework Statement I have to prove that the expression $$\frac{\omega C - \frac{1}{\omega L}}{\omega C - \frac{1}{\omega L} + \omega L - \frac{1}{\omega C}}$$ is equal to $$\frac{1}{3-( (\frac{\omega_r}{\omega})^2 + (\frac{\omega}{\omega_r})^2)}$$ where ##\omega_r= \frac{1}{\sqrt{LC}}##...
  14. N

    MHB Algebraic expression simplification 2(2u+v)/u = 4(v^2-4u^2)/3u^2

    Hi All I am trying to simplify an algebraic expression, I know what the expression should simplify to but I am struggling to simplify it. The expression is: 2(2u+v)/u = 4(v^2-4u^2)/3u^2 and it is supposed to simplify to: 3u = 2(v-2u) I have approached this...
  15. E

    Bounding p-norm expression using p-norm inequality

    problem statement: need to show: ||w||_p^2+||u||_p^2-2(||u||_p^p)^{\frac{2}{p}-1}\Sigma_i(u(i)^{p-1}w(i)) can be bounded as a function of ||w-u||_p^2 where p\in[2,\infty) work done: the expressions are equal for p=2, and i suspect that...
  16. Alexanddros81

    Derive the expression for the work done by the friction force

    Homework Statement 14.6 The coefficient of kinetic friction between the slider and the rod is μ, and the free length of the spring is ##L_0 = b##. Derive the expression for the work done by the friction force on the slider as it moves from A to B. Neglect the weight of the slider. Homework...
  17. Alexanddros81

    Derive the expression for the work done by the ideal spring

    Homework Statement Derive the expression for the work done by the ideal spring on the slider when the slider moves from A to B. Assume that the free length of the spring is (a) ##L_0 = b##; and (b) ##L_0 = 0.75b## Homework EquationsThe Attempt at a Solution Can you check if my solution...
  18. F

    B Simplifying expressions -- What exactly does it mean to simplify an expression?

    What exactly does it mean to simplify an expression. I understand that an expression becomes more simple when you combine like terms but what other conditions are there? Is x(5x+1) more or less simple than 5x^2 +x? Do square roots need to be moved to the numerator?
  19. R

    Can't find correct expression for discharging RL circuit

    Homework Statement After a switch is left for a for many time constants, it is switched to b. find an expression for the total charge that passes through the resistor in one time constant Homework Equations dq/dt = I(t) I(t) = (ε/R)(e^(-tR/l)) The Attempt at a Solution so dq = I(t) dt I know...
  20. Math Amateur

    MHB Putting a superscript before a variable or expression ....

    Can someone help with the issue/problem of placing a superscript before a variable or expression ... as Just and Weese do in their book on Set Theory ... in the expression for a Cartesian Product as follows: Hope that someone can help ... Peter
  21. M

    General group collapsing expression

    How can I collapse macroscopic absorption cross-section of 4 groups into two ? Assuming that the first two groups are fast groups and the other twos are thermal . I am suffering with the following : 1- Do I have to assume that the groups are directly coupled ? 2-Does what apply on the two...
  22. T

    I Anihilation operator expression: is there a typo here?

    For those experienced with this stuff, Weinberg argues (Weinberg, QFT, Volume 1) that an expression for the anihilation operator acting on a state vector when all particles are either all bosons or all fermions is $$a(q) \Phi_{q_1 q_2 ... q_N} = \sum_{r=1}^{N} ( \pm 1)^{r+1} \delta (q - q_r)...
  23. M

    MHB Expression involving roots of quadratic equation

    Given that $\alpha$ and $\beta$ are the roots of a quadratic equation, evaluate $\frac{1}{\alpha^2}+\frac{1}{\beta^2}$. I find this question to be interesting.
  24. R

    Simplification of complex expression

    Homework Statement For the expression: $$E=\frac{E_{0}}{2}\left(\exp\left[\frac{j\pi V}{2V_{\pi}}\right]+j\exp\left[-\frac{j\pi V}{2V_{\pi}}\right]\right)$$ I want to show that if ##V=m(t)-\frac{V_{\pi}}{2}##, then ##|E|^2## can be written as...
  25. rocdoc

    I The unit dyadic.A general expression for?

    Does anyone know of a general expression for the unit dyadic, given in terms of the language of general curvilinear coordinate systems?Perhaps an expression for its components?Perhaps an expression, just appropriate for use with orthogonal coordinate systems?$$~$$ In cartesian coordinates the...
  26. C

    Equilibrium constant expression; why exponents?

    Hello all. I am wondering why we raise the concentration to the exponent of the stochiometric coefficient. I understand why we take the products of reactants or products. For instance, let me give an example to show where I am getting mixed up. Let's say 2A +3B = 8C as a reversible...
  27. S

    Derivation of an expression for centripetal acceleration

    Homework Statement I have derived the expression for the velocity of the satellite v= root of GM/r however I'm struggling to derive an expression for the centripetal acceleration of a satellite orbiting Earth. Homework EquationsThe Attempt at a Solution I'm not entirely sure which equations to...
  28. S

    BIDMAS Evaluating Expression Without Calculator

    Hi there, I'm hoping somebody can help me. I have to evaluate the following expression using BIDMAS rules without using a calculator: 1-2/32 I can get as far as 1-2/9 but the answer is 7/9. I don't understand how to get from 1-2/9 to 7/9 in my head. For instance 2/9 = 0.2 recurring, but...
  29. A

    Derive a general expression for range when launch angle=0

    1. The problem statement, all variables, and given/known data Homework Equations The Attempt at a Solution So basically I took vertical direction formula and I solved for "t". I then took the horizontal direction formula and solved for "x" or we can also call x the "Range" since that's...
  30. D

    Finding an expression for max distance in terms of theta

    Homework Statement Basic projectile motion if you throw from ground level, to obtain a max distance in the x you'd want to throw at a 45° angle right? So as your initial height increases, your throwing angle will decrease and my guess is as your initial velocity increases your angle increases...
  31. lfdahl

    MHB Evaluate the limit of a trigonometric expression

    Evaluate: \[\lim_{x\rightarrow 0}\frac{\sin (\arctan x)-\tan (\arcsin x)}{\arcsin (\tan x)-\arctan (\sin x)}\]
  32. lfdahl

    MHB Rational trigonometric expression show tan^218°⋅tan^254°∈Q

    Show, that $$\tan^2 18^{\circ} \cdot \tan^254^{\circ} \in \Bbb{Q}.$$
  33. K

    Differentiation with respect to a complex expression

    Homework Statement Homework Equations $$(x-a)(x+a)=x^2-a^2$$ The Attempt at a Solution I have to express ##~\displaystyle x^2+16=f\left( \frac{x}{x-1} \right)## I guess it has to be ##~\displaystyle \left( \frac{x}{x-1} \right)^n-a~## or ##~\displaystyle \left( \frac{x}{x-1} \pm a...
  34. B

    Need help deriving an expression for dy/dt

    Homework Statement I need help finding the appropriate expression to use to add a "new calculated column" to produce a vertical velocity vs time graph in Logger Pro. The lab consisted of a ball tied to a rope, creating a pendulum. The Go! Motion sensor was set up to record the oscillations. The...
  35. J

    I Help with expression ##F(it)-F(-it)## in the Abel-Plana form

    I´m having a problem with the value of the expression ##F(it)-F(-it)##, found on the Abel-Plana formula, where $$F(z)=\sqrt{z^2 + A^2}$$, with ##A## being a positive real number (F(z) is analytic in the right half-plane). Well, I know the result is ##F(it)-F(-it)=2i\sqrt{t^2 -A^2}##, for...
  36. davidge

    I What does the 0-ket in this state function expression represent?

    I would like to know what the "0-ket", called vacuum state and used in the following expression, represents $$\Psi(x,t) = \int d^3x <x| \ a^{\dagger}(x) \ |0>$$ I have rewritten the expression for the case of just one ##x##. The expression above is usually presented with ##(x_1,...x_n)## (n...
  37. pairofstrings

    B How to build an equation or expression?

    Hello. I want to be able to create any mathematical equation or expression. So, one thing I want to confirm is that, to create any complex equation or expression, I should make use of Order of Operation - PEDMAS or BODMAS. Correct? The Order of Operation governs the result, and the Order of...
  38. M

    MHB Can you help me factor the expression x^4 - 15x^2 + 9?

    Factor the expression. x^4 - 15x^2 + 9 Let u = x^2 Let x^4 = (x^2)^2 u^2 - 15u + 9 Must I use the quadratic formula here or completing the square?
  39. M

    MHB Factor Fourth Degree Expression

    Factor. x^4 + 2x^2*y^2 + y^4 Must I change x^4 to (x^2)^2 and y^4 to (y^2)^2? Let u = x^2 Let v = y^2 (u)^2 + 2uv + (v)^2 Where do I go from here?
  40. M

    MHB What is the Factorial Expression for (ax + b)^(-1/2) - [sqrt{ax + b}]/b?

    Factor (ax + b)^(-1/2) - [sqrt{ax + b}]/b This one is tricky. Can someone get me started?
  41. M

    MHB Factoring Fractional Expression

    Factor (x^3/8) - (512/x^3). LCD = 8x^3 (x^6 - 8(512))/8x^3 (x^6 - 4096)/8x^3 [(x^3 - 64)(x^3 + 64)]/8x^3 In the numerator, the expression (x^3 - 64) is the difference of cubes, right?
  42. M

    MHB Factor Fractional Expression

    Factor [(a + b)^2]/4 - [a^2b^2]/9 Can someone get me started?
  43. C

    MHB Proving expression is always positive

    I am trying to prove that $$ x^4+4096y^4+450x^2y^2-2304xy^3-36x^3y $$ is positive for all positive $x$ and $y$. I also have the condition $x>16y$ though I don't believe this is needed to prove positivity as I've plotted the function for varying $x$ and $y$ and it always seems to be positive...
  44. R

    Expression for the instantaneous angular velocity

    Homework Statement The directed beam from a small but powerful searchlight placed on the ground tracks a small plane flying horizontally at a fixed height h above the ground with a uniform velocity v. If the search light starts rotating with an instantaneous angular velocity ##\omega_0## at...
  45. M

    MHB How do you factor expressions like 3(x + h)^4 - 48(x + h)^2?

    Precalculus by David Cohen, 3rd Edition Chapter 1, Section 1.3. Question 32c. Factor the expression. 3(x + h)^4 - 48(x + h)^2 Solution: Factor out 3(x + h)^2. 3(x + h)^2[(x + h)^2 - 16] Simplify the quantity in the brackets. 3(x + h)^2[(x + h) - 4][(x - h) + 4] Is this right?
  46. M

    MHB Is it necessary to expand the quantity before factoring the expression?

    Precalculus by David Cohen, 3rd Edition Chapter 1, Section 1.3. Question 29c. Factor the expression. 4a^2b^2 - 9(ab + c)^2 Must I expand the quantity (ab + c) before factoring?
  47. Daniel McKinley

    How to simplify cube root expression

    ]Homework Statement Solving the cubic equation x^3 + 6x = 20 by using formula gives (10+ sqrt(108))^1/3 - (-10 + sqrt(108))^1/3 How do you show that this comes out exactly 2? No calculators allowed.Homework EquationsThe Attempt at a Solution Tried cubing the expression and tried using the...
  48. mkematt96

    Finding Magnitude of complex number expression

    Homework Statement We are given Z, and are asked to find the magnitude of the expression. See attached picture(s) Homework Equations See attached pictures(s) The Attempt at a Solution When I solved it on the exam, I did it the long way using De Moivre's theorem. I ended up making a few sign...
  49. Noora Alameri

    I Maximally entangled state expression and generalization

    Hey everybody,, I have question related to the expression of the maximally entangled state.. I know that that for W-state its given by ( For three qubits) : psi=(|100>+|010>+|001>)/sqrt(N) and for Disentangled state ( for three qubits) its given as : psi=|111> Where one and 0 represent the...
  50. S

    Why must this expression for the curl be wrong?

    Homework Statement Without explicit calculation, argue why the following expression cannot be correct: $$\nabla \times (\mathbf{c} \times \mathbf{r}) = c_{2}\mathbf{e_{1}}+c_{1}\mathbf{e_{2}}+c_{3}\mathbf{e_{3}}$$ where ##\mathbf{c}## is a constant vector and ##\mathbf{r}## is the position...
Back
Top