feivel-

Pegger is absolutely right – it doesn’t necessarily have to be gravity. However, on our planet, that is the ONLY acceleration means we have (we do not have a string tied around us and the center of the earth!).

That is basic, my friend. Look at the frictional force equation I wrote before – that’s the force due to friction. Nothing more, nothing less. There needs to be an acceleration for the normal force to be >0; that comes from the acceleration due to gravity, in our case of us standing on planet earth.

And mto – it does not matter; as long as each electron in the orbital have opposite values.

feivel-

Actually, if gravity would cease, you would fly off the earth. There would be absolutely nothing holding you to the ground. And friction would also cease, because the equation for friction:

F(f)=uF(n)

where “u” (actually, really the Greek letter mew, the frictional coefficient), and N(n) is the “normal force”, which is

F(n)=mg

where “m” is the mass and “g” is the gravitational constant. So if “g” is zero, then F(n)=0, and consequently, F(f)=0 (there would be absoluteley no friction).

So…gravity is the only thing holding us here 🙂

feivel-

The answer to that question is that the force of gravity on earth is greater than the “force” that accelerates you away from tangential velocity that would be expected due to the rotation of the earth. To put that in easier terms to understand: we don’t feel as if we are falling off the earth because gravity keeps us here. Without gravity, we would “fall off” the earth as well.

According to Newton’s Second Law:

F=ma

where “f” is force (Newtons), “m” is mass (kg), and “a” is the acceleration of the object (meters/second^2). Every force you feel has its roots in this fundamental equation.

Therefore, when one stands on Earth, we don’t feel any outside force of the movement of earth, because there is no acceleration (velocity of the rotation of Earth is constant). Therefore, F=0. However, in the case of an accelerating car, F>0.

To answer the question of getting dizzy on a roller coaster/merry-go-round: that has to do more with changing perspective; on Earth, everything moves together in unison. But on a roller coaster, the perspective is not moving at the same speed as you are – therefore, there can be dizziness.

ultimateskier-

I think it would help you if you knew what “i” is. It is (-1)^1/2, or “the square root of -1”. If you then square “i”, the radical falls off, and you are left with -1.

((-1)^(1/2))^2 = -1

Well the textbook I used was Moore’s Clinically Oriented Anatomy, which is a good book, but I don’t know if you should get it yet if you might use a different textbook in your school.

Thanks for the advice – I’m thinking about getting Netter’s Atlas as well.

Don’t worry, you’ll learn all this in medical school, if that’s what you’re studying for. 🙂

How did you guess? 😉 But that’s good to know!

But doesn’t phosphoglucomutase convert glucose-1-phosphate to glucose-6-phosphate? Or am I mistaking that with another enzyme?

Finally – let me ask a question:

What is beta oxidation, and how does it help camels?

how do you explain the quatum theory (chemistry) to a grade 12

and how do you connect it to bohr’s experiment

To answer your question – quantum theory (at least in depth) is not something that’s taught in high-school level physics, neither in undergrad college. However, what I think you mean is the quantum theory of electronic configuration, which I am more than happy to explain:

Quantum theory of electronic configuration defines the “address” of an electron. According to the Pauli Exclusion Principle, no two electrons may have the same address (which makes sense – no two electrons can be exactly in the same place at the same time!).

There are four “quantum numbers”, which define many characteristics of electrons.

FIRST QUANTUM NUMBER: This is denoted as “n”, and defines the shell in which the electron is occupying. The value for n may go from 1-infinity.

SECOND QUANTUM NUMBER: This is denoted as “l”, and really refers to the angular momentum of the electron (something that we are not going into at the moment). The value for “l” goes from 0 to n-1, and refers to which subshell (s,p,d,f, etc) the electron is in.

THIRD QUANTUM NUMBER: This is also known as the “magnetic quantum number”, and refers to the orbital in the subshell that the electron is occupying. Its values range from -l to +l (thats “l”, not “1”).

FOURTH QUANTUM NUMBER: Also known as the “spin” of the electron, this refers to which way the electron is rotating around it’s axis (much like the planets do). The possible values are +1/2 and -1/2.

The reason for any of the above quantum numbers is extremely complicated, as it goes into some serious quantum theory that is beyond my comprehension in its entirety.

As to Bohr’s experiment – I’m not quite sure as to what you are referring to.

Hope that helps!

pascha bchochma-

Hexokinase is the enzyme that starts off glycolysis in eukaryotes. It phosphorylates glucose on the 6 carbon to create glucose-6-phosphate. This requires the input of 1 ATP molecule to drive the reaction forward.

However, if glycogen is the starting reactant of glycolysis, a different enzyme breaks down glycogen into glucose-1-phosphate units (starch phosphorylase), and then hexophosphomutase isomerizes the molecule to glucose-6-phosphate. This does not require the use of ATP.

While hexokinase is normally used in almost all cells in our body, a competing enzyme, glucokinase, is used by the liver to eventually create glycogen from glucose. So which enzyme is uses, and when?

Due to the fact that the Km of hexokinase is around 1 micro-molar and glucokinase has a Km about 100 times that, hexokinase works best at low glucose concentrations (which makes sense- we want our glucose to be utilized for cellular respiration), while at high glucose concentrations glucokinase kicks in (more glucose=storage as glycogen).

RABBAIM- Those books look very interesting! I think I’m going to order them very soon.

Always runs with scissors fast – it’s never too late; I’ve heard of someone who went to med school at 52 years old!