Bio Questions from TPR Hyperlearning

[thebillsfan]

Sorry that I have so many questions!

Why is it impossible to alter the deltaG of a reaction without altering the equilibrium? Why do the two have to go hand in hand?

When during the cell cycle are centrioles assembled and when do they migrate to opposite poles of the cell.

Do RBCs have any DNA?

Do adipose tissues synthesize fats?

What is an endosome?

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[G1SG2]

Sorry that I have so many questions!

That's okay, it's what the forum is for

Why is it impossible to alter the deltaG of a reaction without altering the equilibrium? Why do the two have to go hand in hand?

Think about this equation: delta G=-RTlnKeq.

When during the cell cycle are centrioles assembled and when do they migrate to opposite poles of the cell.

They are made in the growth phases of interphase, as are all other organelles/"stuff" that the cell needs. Prophase I of mitosis is when they migrate to opposite poles of the cell.

Do RBCs have any DNA?

No, RBCs don't have nuclei or any other organelles. They have a lifespan of 120 days, and rely on glycolysis for ATP.

Do adipose tissues synthesize fats?

Yes, along with the liver.

What is an endosome?

It's a membrane bound vesicle that usually brings things to the lysosome for degradation. Remember receptor mediated endocytosis and other transport methods inside the cell? They package things into the endosome to bring inside the cell. Think of it as a little ship moving through the cytosol ocean.

 

[sv3]

That's okay, it's what the forum is for



Think about this equation: delta G=-RTlnKeq.



They are made in the growth phases of interphase, as are all other organelles/"stuff" that the cell needs. Prophase I of mitosis is when they migrate to opposite poles of the cell.



No, RBCs don't have nuclei or any other organelles. They have a lifespan of 120 days, and rely on glycolysis for ATP.



Yes, along with the liver.



It's a membrane bound vesicle that usually brings things to the lysosome for degradation. Remember receptor mediated endocytosis and other transport methods inside the cell? They package things into the endosome to bring inside the cell. Think of it as a little ship moving through the cytosol ocean.

someone obviously knows their sheaaat real well

 

[thebillsfan]

WHY do adipose tissues synthesize fats when they're already storing so many? That doesn't make sense to me.

Also, with endosomes...can they originate from the Golgi OR from endocytosis?

Is it considered "endocytosis" only if its at the membrane. ie, when the endosome fuses with the lysosome, that's not endocytosis right, since an endosome isn't being formed (rather the endosome's contents are just being spilled into lysosome)

similarly, all of the vesicle transport in the golgi as a protein makes its way from the cis face to the trans face is not endocytosis either, since in every situation the contents are being fused into the next flap of golgi?

I realize symport and antiport mechanism send ions down their gradients, but is this always the case? The sodium/potassium pump--would that NOT be an example of antiport just because its active transport?

 

[Charles_Carmichael]

WHY do adipose tissues synthesize fats when they're already storing so many? That doesn't make sense to me.

Also, with endosomes...can they originate from the Golgi OR from endocytosis?

Is it considered "endocytosis" only if its at the membrane. ie, when the endosome fuses with the lysosome, that's not endocytosis right, since an endosome isn't being formed (rather the endosome's contents are just being spilled into lysosome)

similarly, all of the vesicle transport in the golgi as a protein makes its way from the cis face to the trans face is not endocytosis either, since in every situation the contents are being fused into the next flap of golgi?

I realize symport and antiport mechanism send ions down their gradients, but is this always the case? The sodium/potassium pump--would that NOT be an example of antiport just because its active transport?

Adipose tissue synthesizes fat because it receives fat as fatty acids and glycerol; this needs to be resynthesized into triglycerides in order to store it. If adipocytes could not resynthesize fat, they wouldn't be storing any fat at all since they don't receive it in the form of triglycerides.

An endosome is basically any membrane-bound compartment inside the cell. A membrane-bound vesicle headed for exocytosis could also be considered an endosome.

Endocytosis is when a cell takes in something from the outside by engulfing it with its plasma membrane.

Symport and antiport refer to which way all the ions are being transported, NOT their gradients. Symport means that all the ions are being transported in the same direction (ie. out of the cell or into the cell) while antiport means that that ions are being transported in opposite directions (ie. the Na+/K+ pump). It has nothing to do with type of transport. Hope this helps.

 

[thebillsfan]

oh ok, well TPR made it seem like symport was a type of transport. thanks everyone

 

[rocuronium]

oh ok, well TPR made it seem like symport was a type of transport. thanks everyone

I think you may have misunderstood what Kaushik wrote. Symport is indeed a type of transport.

What Kaushik is saying is that when determining the type of transport, it is the direction of ionic movement that is considered, not the existing concentration gradients.

By using what Kaushik said we can answer your original question. The answer is that symport and antiport do not always transport ions down the existing concentration gradient. If it helps, you can think of the concentration gradient as irrelevant when determining the type of transport. Instead, look at directions of transport and decide from there.