# STUPID QUESTIONS THREAD

/SQT/ all questions are stupid edition

I'll start:

this one is for biochemists/molecular biologists, what the flying fuck constitutes a low or high Km value?

old thread is dead >

How do I actually use the MIT OCW?
(I mean the physics and chemistry lectures which have no video)
I'm self studying math physics and chemistry for a scholarship test in 2 months, would you mind giving me advice?
And yes, I am retarded for not knowing how to approach this.

>this one is for biochemists/molecular biologists, what the flying fuck constitutes a low or high Km value?
Km is a parameter in the Michaelis Menten equation.
From the equation you can see that when [S] = Km then V = 0.5Vmax.

so (bear with me) if the value is over 0.5 we can assume it is relatively "high" and if it falls below, it is low?

I have 0.98 which according to a paper is high, but my curve looks like a curve for a high Km value

i need to get drunk

pic related

If there are assigned readings, do the readings.

If there is homework and exams, attempt to solve the homework and exams.

What exactly are you unsure about? It's just a load of learning materials

where does our consciousness come from

How do I manage to study all this by june 15th?
(I don't need to master everything, I just need to be able to solve problems fast as fuck. 1hr exam)
I would really appreciate some help, if not the correct place to ask just point me to where I have to go. Thanks

how do I determine for what values of k
$(n^2-1)^p(n-1)^{p+1}+k$ is divisible by n?

That picture is kind of misleading, since the enzymes obviously have different vmaxes. If they had the same vmax, the one with the lower km would just reach it faster.

once when i was a little kid i bought some offbrand oreos, i thought that heating them in the microwave would make them taste better and i set them there for a minute.
The oreos packaging started making sparks and i thought it was cool so i let it happen for the whole minute.
When i opened the door i saw the cookies there without the package.
My question is where did the package go and what happened to its components, where they still in the cookies?

I hope you didn't eat them. I assume they became plasticized oreos,

Doing pure math. Got accepted for transfer to UCLA and waiting to hear from Berkeley. If I get accepted to both which should I take? In grad school I'd be looking to do something with mathematical physics or pure math in geometry, topology, or algebra. I know that UCLA is a good math school and is strong in analysis and number theory which I have essentially no interest in. Their undergrad program looks great though.
Idk the best plan of action here.

was asked on a cs exam about matrix transformation. the matrix was $\begin{bmatrix} x \\ y \\ 1 \end{bmatrix}$, which was a representation of (x, y). we were suppose to give the 3x3 matrix that would give the transformation to (x + 2, 3y). i think i answered $\begin{bmatrix} 2 & 0 & 1 \\ 0 & 3 & 1 \\ 1 & 0 & 0 \end{bmatrix}$, but pretty sure that was wrong.. anyone know how to solve this? pretty sure its for image processing

Start by expanding the powers and figure out which term(s) leave a remainder when divided by $n$.

All the talk about sending micro satellites to alpha centauri at 20% the speed of light, have anyone how they're planning to slow the nigga down once it gets there?
Or will it just be a fly-by?

$\begin{bmatrix} 1 & 0&2 \\ 0& 3 & 0 \\ 0 & 0 & 1 \end{bmatrix}$
Would output the vector
$\begin{bmatrix} x +2 \\ 3y \\ 1 \end{bmatrix}$
Both are fine schools. As someone who goes to Berkeley, I'm fairly sure the only difference is location in a lot of ways. Granted, Berkeley is more prestigious in some people's view, but that actually makes very little difference.

I got this question wrong obviously.. can anyone explain what I am misunderstanding in my working? I'll reply to my post with my working on my mini whiteboard.

It's only dirty because it's cheap, I only started using it 3 days ago

How do I find a value of a such that the system of linear equations is inconsistent?
$\begin{cases}a + y + 3z = 1\\ x + ay +3z =1\\ x + 2y +az =3 \end{cases}$

is the answer 4? not sure if I worked it out right though. if it is I can expalin it. been a while since highschool maths lol.

it's 10/6 = (10+x)/10
the triangles are similar

That's just the fraction flipped the other way. I thought that shouldn't matter?

The answer isn't 4, it was a fraction (20/3). I'm revising high school math at the moment, it's actually kinda fun.

>The answer isn't 4, it was a fraction (20/3). I'm revising high school math at the moment, it's actually kinda fun.
oh yeah, sounds like it, I should get back into it one day!

the only reason similarity works is because everything is oriented the same way

Never heard of Euclid or Scalar Coefficient, will look it up now.
So when I do this, should I then always put the larger part of the fraction on top or something?

I want to get a scholarship to study in england, is there one for a good engineering university?
I am from latam.

I am trying to find power dissipated on a voltage dividers resistors.
Is (V^2)/R same as (I^2)*R

Whats a general element of a matrice?

How do you name something attached to a substituent? Say I had a chlorine attached to a carbon attached to the parent chain?

treat it as a single side chain and name it how you normally would

just remember that in organic chem, a name can never be too convoluted

cancel them out

you see that the first and 2nd equations for example both have 3z, so if you minus one from the other, you will remove the z term

do this until you are only left with an a term

you might need to substitute somewhere but it's not hard

Thanks

>how they're planning to slow the nigga down once it gets there?

They use sails for propulsion, so presumably the stellar wind from the approaching star will slow them down.

Question for Biologists/Biochemists

How do you analyze genes? How do you extract DNA, how do you know where a gene ends, how do you look at it? Basically how does gene engineering work and why can't we just change our genes however we like?

>60x
should be 6x

arctan(6/10) to get angle at point A (I'll call that angle 'a').

tan(a)=10/(10+x)
rearrange to: x=10/(tan(a)) - 10

Learning to trig is way more useful than learning scalar coefficient, but scalar coefficient is pretty simple. 6/10=0.6. 10/0.6=16+2/3. 16+2/3-10=20/3

How does one write matrices like this? (as in format on Veeky Forums)

Oh god I'm retarded

Just got a new processor and can't hit 30% even.

What are some good science-related programs (e.g. simulation etc.) that make heavy use of the CPU while teaching you something too? Preferably molecule related and such.

Is there maybe a program where you can analyze large macromolecules like hormones labeled with their active sites and other such details?

genetic analysis is generally mathematics, calculating the probability that an allel will find its way on a certain number of individuals, etc (ofc it is much more than that)

extracting dna, lets see, you grab a fruit fly, you mash it, you put it in an eppendorf tube, you add buffer, you shake dat_bad_boy, you add a bunch of other chemicals, centrifuge here and there, you get fat as a pellet and the dna in the liquid (that i remember), and theoretically you should have dna juice

if you wanna amplify it, you add a primer, dna polymerase and do some pcr and you get a bunch of dna copies which you can analyse via gel electrophoresis

a gene is a hard thing to describe imagine a long string, and in this string you have a starting sequence, and you have pieces of dna (bases) that code for something useful usually (proteins), there are many empty spaces between these sequences, and the ones that are not empty will be translated to something, then comes mRNA and does a copy of this, this copy is then translated with the help of tRNA into aminoacid chains and then proteins

en.wikipedia.org/wiki/Central_dogma_of_molecular_biology

you can change the genes ofc, rape the shit out of them, but you have countless cells and a myriad other factors coming into play, plus theres also "ethics" which some people care about. we're getting there though, look into cas9/crispr

hope this was of some help, if im wrong, someone correct me

>I know that UCLA is a good math school and is strong in analysis and number theory which I have essentially no interest in

It doesn't really matter at all for you. Try to visit both campuses and decide where you'd rather live.

Holy shit I just realized I'm fucking stupid and don't get Biology at all

I have a programming problem, but it's really a math problem in disguise, so it's not really suitable for /g/:

I have a function which takes a byte as input and checks it against all cyclic permutations of another byte. This works fine, until I try to introduce starting offsets to one of the strings, and then I'm lost.

pic related is the function. In this case, the problem is in the first half of the function. I am trying to check for a given surface by checking the bit and the two adjacent bits (with curcular shifts) to see if they are free. (1 = not free, 0 = free). each bit position corresponds to a free adjacent cell to a given tile on a 2d orthogonal grid.

So in this case, my input string is an arbitrary byte, my comparison string is the cyclic permutations of 00000111, (cyclically) offset by one so it is centered on the bit of the input we are concerned with.

The function does not work correctly in its current form, and I think it has to do with how I'm approaching the problem. Any math people able to help me here?

using latex inside $or [eqn] blocks people tend to think biology is just memorising the name of things, while that is partially in the right, it is also much more biology is too broad, therefore it has many branches, if you're interested just read introductory textbooks like campbell biology, then see where that takes you just think chromosomes is highly compact dna, which then gets copied and that gives you proteins which are the worker bees of organisms Guys I have a 2 samples each with 2 features measured. How do I test the p-value to see how likely it is that the 2nd sample differs from the first? Wherever I read about t-test/z-test, they keep referring to population.. in my case is the 1st sample the population? Cause technically it's a sample, and both samples have the same number of data points (20) the shear stress graph in a monodimensional beam represent forces parallel or perpendicular to the length of the beam??? ok i decided on 2-samples paired t-test, hope it's good >Just got a new processor and can't hit 30% even. Curious, what system did you get? (sorry no answer to your question) > shear Perpendicular So, uh, how much mathematics would I have to know that the example in the link makes sense? en.wikipedia.org/wiki/Abstract_nonsense I'll be transferring to a university from a community college. What year would I be considered? Second or third year? Can a computer engineer work on robotics field? I'm currently taking an intro to proofs class and came upon pic related. I'm pretty sure I negated the statement correctly and I can't understand why the negation is false. I think the negation is true because for every natural number, I can find a real number to make that statement true. Thoughts? You've written it correctly (though 'such that' is unnecessary), but the negation is read 'there is a real number x such that all natural numbers are smaller than or equal to the absolute value of x' which is obviously false. You switched the order of the quantifiers around, which you cannot do unless they are the same. Thanks user, that makes sense. Just finished a course which dealt heavily with MM kinetics. Km is essentially a dissociation constant -- although it classically is considered as different than Kd, but that's an easy way to conceptualize it. As the concentration of substrate increases, reaction velocity approaches a maximum (Vmax, denoted as 1.0). Km, like a dissociation constant, is the point of concentration of substrate in which velocity is 1/2 of Vmax, or 0.5. What constitutes high or low Km is centered around the protein's affinity for its ligand -- which is typically the experimental substrate. Low Km means the enzyme has a higher affinity for substrate, and therefore approaches Vmax more rapidly w.r.t. increases in [Substrate]. Hope that helps. The reply you got is mostly accurate, but I can give you a more concise and simple answer to each question: There are many ways to analyze genes, and the method is chosen based on what information you're attempting to collect. I can tell you about some specifically if you're still here and curious about certain techniques. Extracting DNA is typically done by cell fractionation and then centrifugation. Nucleic acids will occupy their own "band" in the test tube as determined by sedimentation characteristics such as density. Think of how oil and water separate. The end of a specific gene is coded for by highly conserved "stop" codons -- UAG, UGA, or UAA. These are read by the molecular machinery to terminate the process, such as transcription of a gene into mRNA. You can look at genes several ways. Analysis of genes can be done by running them on a gel, as stated by the user here . Or if the sequence is known, you can engineer a complementary sequence, stick those single strands of nucleic acid to a glass surface, then wash the experimental DNA solution over top of it. Your gene sequence of interest will bond specifically to form double stranded DNA. This is called a DNA array. Again, there are other methods if you want to know specifics. We can change genes, but there are plenty of issues surrounding the idea. A typical way is by taking the native DNA of a bacterium (called a plasmid), such as E. Coli, and inserting the gene of interest into it, then using viral machinery to insert into the patient and replicate the new, desired genes. Those are the short answers. It's important to know that the genetic code is filled with non-coding portions, ie, sequences that are never transcribed into mRNA and translated into proteins. But these sequences are important because we can use them to understand where specific genes occur in chromosomes, and target them to be removed, replicated, studied, etc. Yes. Machine vision for one has a lot of low level work. New Sensors in general are always being developed >molecular machinery This is another thing I don't get. "What" exactly "reads" the genes? Or more precisely how do genes even work? How do they decide when to use which sequence of the DNA and for what? How for example is an organs grown? A heart, a brain, a lung? How do they know which macroshape to take? And with that I mean I don't even understand what "they" are. Shit I'm so fucking stupid. Brainlet herte, what rule is this? [math] 7^{k}-2^{k} \equiv 7^k-7^k2^k+7^k2^k-2^k$

How difficult would taking Differential equations and Calculus 3 at the same time B if you've aced calculus 1 and 2?

I dunno
That you can add 0 and it doesn't change the value?

The negation is that there exists a real number x whose absolute is greater than or equal to any natural number. Assume this is true. Then 1+ceiling(|x|) is a natural number. But 1+ceiling(|x|) must be greater than |x|. So there is a natural number greater than x. This is a contradiction of our assumption so the assumption must be wrong.

The central dogma of molecular biology is:
DNA --(transcription)--> mRNA --(translation)--> Protein

Genes (DNA) are coded by four nucleic acid bases, ATGC. It's important not to get hung up with thinking of these as "letters." In reality, they are large molecules with unique structures. The elements they are made of have different charges and characteristics which allow them to be recognized by necessary enzymes, such as the ones that transcribe DNA into mRNA. Genes that are destined to become proteins are typically unique and actually nonsensical sequences relative to the enzyme until they reach the mRNA stage -- where three letter codons of AUGC denote specific amino acids to be bound together into proteins. There are common promoting sequences at the "start" of coding genes which enzymes have evolved to recognize through chemistry and binding characteristics. Transcription and translation are really just chemical reactions that occur wherever the right enzyme can bind, and it will continue until it hits a stop sequence (in DNA) or a terminator structure (mRNA). Coding genes are sequences that follow promoters, this is how the cell "decides" which genes to use. The way that organs form their shapes is denoted by genetic code and the characteristics of the proteins that ultimately form the organ. A liver for instance, is coded by chromosomal genes initially. It starts small in development, as a cluster of proteins transported to and binding in a specific area, and grows with the rest of the body in relation to necessity. Systems such as cellular signaling are used to activate certain genes in times of need, like human development.

You are asking a lot of great questions which are too complex to answer simply, and you would be best served studying something like biochemistry to give yourself context. These mechanisms are nothing more than inevitability, determined by chemical physics and thermodynamics. They've evolved in complexity over time.

Trying to learn about hyperbolas.

I am told that $y = \frac{1}{x}$ is a hyperbola, which it looks like rotated 45 degrees about the origin. I am also told that $x^{2} - y^{2} = 1$ is the equation for a basic hyperbola. What kind of algebraic manipulation is necessary in order to see the first equation in terms of the second equation?

Ah this answers a lot, thank you.
So it's enzymes that decode DNA?
But where do enzymes comes from then?

Can you recommend me some beginner books for me to get into biochemistry?

Say you have one day off every week, and the rest of your week is filled with stressful mental work and moderate exercise -- is it normal to feel very fatigued on your day off?

Yep. Cellular machinery refers to enzymes (nearly all enzymes are made of protein). All amino acids, and therefore proteins, come from mRNA, which is coded by DNA. Similarly to how the nucleic bases AGTC have unique characteristics, the 20 amino acids that are coded by mRNA have unique chemical compositions which can be arranged in essentially limitless ways to achieve many tasks. Pic related is a visual example of the protein "Kinesin." You can see how it appears to be walking across another protein. In reality, it binds to a spot on the protein inevitably because of its unique make-up (maybe one amino acid in the "foot" is positively charged and an amino acid on the target protein is negatively charged, for instance), and then the change of the system after it binds causes it to swing into the next position, and so on. I think it's important to take "intelligence" and purpose out of the question when considering these things. Enzymatic activity, like the enzymes tasked with decoding genes, is as unsurprising as watching a ball roll down a hill once you understand the make-up of the protein and its target.

I would recommend studying biology up to genetics and cell and molecular biology, and all of chemistry and chemical physics. Once you get up to the level of biochemistry, look for Voet, Voet, and Pratt -- Fundamentals of Biochemistry. I liked that one a lot.

I was the first guy who replied to you, I recommended you campbell biology, to understand biochemistry you will need some knowledge about general chemistry, as well

gen.lib.rus.ec/book/index.php?md5=66F6EE344E4EDE7EFDB0C50EE0BBA420

it's a lot of info to process at once, try khan academy first, if you're still interested then start reading biology -> genetics -> biochemistry

if you still wanna jump into biochem, try lehninger biochemistry

Thanks a lot

Here we use | instead of such that!

what is love?

Dunno, i have a bad DSM

So I am finishing up a term long research project, and I have a bit of an issue. This project deals with high school dropout rate. I have Gender and Ethnicity as variables (Which are divided into male/female white/black/etc)
I found the dropout rate for each of the schools I am examining fine, but when I look to the actual number of students that dropout I hit a brick wall. The resource I found only lists students who dropped out above ten, anything

Throw them into Excel or your analysis software of choice and divide everything by ten, take the

If homeostasis is at 98°F then why does almost everyone start sweating at temperatures at or exceeding 80°F ?

Alright thanks. I was just afraid of my professor bitching at "lol ur lazy why didnt u find the data" or some shit.

I'll just throw a paragraph in my paper about it since Virginia/California/Flordia all seem to ignore things below ten

At 80 degrees F, there is enough energy in the environment (in the form of heat) to be transferred to our skin and peripheral tissues (which are not at body temperature of 98 degrees F). Sweat helps keep those surfaces cool with evaporation and therefore prevent internal overheating. There's actually almost always water being evaporated out of your skin, even at lower temperatures when you don't feel sweaty -- the perspiration is just too insignificant to notice.

Are there any known biological processes that don't involve either baryons, photons, or electrons?

I've been learning about particle physics, and it seems like most living things just ignore things like neutrinos and muons.

How hard is cryptography guys? I have a background in elementary number theory and a little abstract algebra, and that's it. I'm taking a class next semester and i want to not fail, recommend me some readings guys

If there are 100 chairs, and 99 people, how many combinations can there be, with no extra stipulations?

I keep coming to $$100! / 1!$$ but I think it's wrong. I was being stupid and thinking it equals 100, but then i realised 100! is a big number, and a big number divided by 1 is still a big number.

My waifu thinks it is 100! / 99!

What's the real answer, sci?

Don't use factorials.

You should be doing 100 nPr 99

If I remember this shit correctly.

do you know how to factor large primes?

I mean, there's 100 chairs, there's 99 people.

Meaning there's 1 person left over, so I keep thinking I should divide the total, by the remainder, which is 100! / 1!

What's bugging me is that there are not 100! combinations, since only 99 people actually get to sit in a chair.

If there were 100 chairs, and 98 people, it would make sense because

$100! / 98!$ yields a reasonable answer to the problem, i.e. not 100!.

I have a circuit, pic related assuming that the 40ohm resistors, are in fact motors. and the 2 resistors to the right hand side are variable resistors.
Will varying these variable resistors, change the speed of the motors?

It's 100! assuming everyone's special

your waifu's right if we assume no one is

cuz it's not always the same chair that's empty, so it still contributes to the permutations

yes.
Speed is determined by current.
So lets say you lower the resistance on the bottom variable resistor. The Voltage won't change, but more current will flow down the bottom path. More current=faster motor

So changing the current to one, would change it on the other motor in the opposite direction so to speak
faster motor a = slower motor b
How would I make these independent?

yeah you have a specific amount of current coming from your power source and it gets split up based on the resistance.

what do you mean by independent?

I want them to be controlled seperately, like 2 cars powered by the same power supply
but so i can choose the power to either of them without affecting the other

MAybe something like this

how large

Could AI solve theoretic mathematical problems

yes

theoretically: yes

in reality: no

the limitations of AI are readily apparent if you simply look at the progress of machine language translation

Is there a compact non-rectifiable set in ${\rm I\!R}$ other than the fat Cantor set? What about a bounded open non-rectifiable set?