Bio Questions

[flycd05]

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1) The nucleus contains both DNA AND RNA?? Is this true? I thought it only contains one or the other but according to kaplan, the nucleus contains both (if they're referring to mRNA then yes but not regular RNA right?) Can someone please clarify this simple concept!

2) Which one of the following is a true statement?

a - endocytosis and exocytosis are active transport processes that are ways to move large volumes of substances in and out of teh cell

b - diffusion is the movement of molecules from a lower to higher concentration.

the correct answer is A. However, i thought that B can be true too - doesn't diffusion go from hypotonic (high solvent) to hypertonic (low solvent) so why B false???

thanks guys! 🙂

 

[ramin123]

Look at your own answer carefully-- u answred y!!
high---> to low concentration

 

[flycd05]

Look at your own answer carefully-- u answred y!!
high---> to low concentration

wait, ur saying high conc. to low conc. (hyper to hypotonic) but i thought diffusion was from hypo to hyper (high solvent to low solvent)

 

[drzakisadiq]

i think your mixing osmosis here with diffusion.

Diffusion of anything will result in the movement of material from a region of high concentration to a region of low concentration. You want to maintain balance, so think of it that way.

In osmosis, water will move from an area of low solute concentration (hypotonic environment) to an area of high solute concentration (hypertonic environment). Again the key here is balance, water is moving in order to balance itself out between the two environments.

 

[Xtian]

I believe mRNA is in the nucleus as it messengers the info transcribed from DNA in the nucleus to the ribosome where it meets up with tRNA and rRNA for translation.

 

[Xtian]

when you talk about hypo and hypertonic your usually talking about something in a solvent in relation to the flow of water.

ie: if you got a fish in the ocean, salt water, it's in hypertonic situation so it drinks a lot of water to keep from shriveling up...look at the e in hypertonic to remember

if its a fresh water fish its in a hypotonic situation so it doesn't drink water so it doesn't explode... look at the o in hypotonic to remember a cell getting all filled up with water

 

[PooyaH]

Yeah hypertonic and hypotonic refer to osmosis not diffusion!