what is the relationship between phosphate ions and mitosis?

[Guest angel]

hi, ive been asked to plan an investigation to find out if there is a relationship between the concentration of phosphate ions in nutrient solutions and the number of cells dividing by mitosis in root tips (i'm assuming on using hydroponics obviously) but im really stuck! can any of you lovely people help me out, either with the scientific knowledge or actual investigation? Thanks, Angel (that is my real name please dont laugh at it!)

[Skye]

I'm not into plants but maybe try this: grow a species under different phosphate levels, then after a period of time produce stained slides of the root tips. Under a microscope count the number of cells that are undergoing cell division (the chromosomes will be dark and distinct) and the number that aren't (chromosomes probably blurry and harder to see). A higher proportion of cells undergoing cell division should indicate that the root tip is growing faster.

[Guest angel]

ooooo thank you!!!! any thing on the scientific knowledge bit? why are phosphate ions needed for mitosis? is it to do with atp and stuff? angel xx

[Guest Dark Angel]

ive also been asked to investigate it But i cant find no research and i need serious help guys, so if u find any research tell me okay

[Guest no1_potter]

Think about it! in the nucleotides of DNA what are there? nitrogen containing bases, pentose sugars, and PHOSPHATE GROUPS. Therefore when cells are dividing mitotically, the cells need enough phosphate so that they can replicate the chromatin etc.

[Guest Dark Angel]

hey thanks this is much better. Also i found tha if there are no phosphate ions then there are no DNA made and no replication and no cell division

[FatJudge]

is there a relationship between the concentration of phosphate ions in nutrient solution and the number of cells dividing by mitosis in root tips?

 

can sum1 just give me an answer and an xplanation 2 this question plz as i have to giv it in on friday 29th april.

 

safe innabit.

[Loului]

Which page is it in the biology 1 book? I'm not sure I can find it =(

Anyway, from my preliminary work I have found that the optimum amount of phosphate is around 0.25 grams per dm3 of nutrient solution and that a concentration any higher than this inhibits the growth. The only problem is....i'm not sure why!!

[invert_nexus]

Another thing to consider is that phosphate is the most commonly used power source of the cell. ATP. The energy is provided in the phosphodiester bond and powers most cellular functions. There are also some reactions fueled by GTP but, come to think of it, they also depend upon phosphate.

 

Now. As to a connection between phosphate in a solution, I'm unsure. I imagine a quickly growing organism would require additional phosphate, not only for power, but also for the phospholipid cell membranes. As well as for use in the backbone of DNA.

 

Phosphate is a very important molecule for the cell.

 

I'm unsure how to apply this to the needs of your 'investigation' but these are all areas which you might need to consider. But then again, the actual use of the phosphate might be secondary to actual experimentation. In which case you'd just want to set up a variety of nutrient solutions with the only varying factor being the levels of phosphates and to observe the results.

[Guest boogaloo]

sruggling with this too! Where did you get the info about the concentration levels?

[neo007]

Not really a plant biologist, as i study only human biology, but...

 

fact1: membranes are made out of a phospholipid bi-layer

fact2: during mitosis DNA replicates many many times

fact3: ATP...phosphate!

 

During mitosis, basically one cell becomes two, thats where fact 1 comes into place. Also mitosis can only occur if DNA can replicate,,,in order to do this...you need many constituents...above all ....phosphates, because without this you wouldn't get the sugar-phosphate backbone in DNA.

Thirdly i would think that you would need energy in order to 'drive' mitosis...therefore the more ATP the better.

You probably wouldn't be able to explain the relationship between phosphate conc and mitosis with just one theory, as there's a number of different explanations, but most importantly DNA replication.

 

hope what i've said makes sense and helps some of you

[Loului]

Oooooh, I have found stuff to answer my own question and I thought it may benefit some of you too.

 

"Phosphorus (P) is an essential element classified as a macronutrient because of the relatively large amounts of P required by plants. Phosphorus is one of the three nutrients generally added to soils in fertilizers. One of the main roles of P in living organisms is in the transfer of energy. Organic compounds that contain P are used to transfer energy from one reaction to drive another reaction within cells. Adequate P availability for plants stimulates early plant growth and hastens maturity. Although P is essential for plant growth, mismanagement of soil P can pose a threat to water quality. The concentration of P is usually sufficiently low in fresh water so that algae growth is limited. When lakes and rivers are polluted with P, excessive growth of algae often results. High levels of algae reduce water clarity and can lead to decreases in available dissolved oxygen as the algae decays, conditions that can be very detrimental to game fish populations."

from http://www.extension.umn.edu/distribution/cropsystems/DC6795.html

 

"Phosphorus stimulates root growth and flowering in

plants and is needed for energy transfer reactions in plant

cells. Shallow rooted plants, such as carrots, onions, and

radishes need more phosphorus than deep rooted plants

such as corn, beans or peas. The optimum amount for

your soil will in part depend on the crops that you grow.

...

Excessive phosphorus will not be detrimental to plant

growth. However, adding more phosphate either from

fertilizer blends or organic sources will not benefit crops

and may contribute to environmental degradation."

from http://www.ipcm.wisc.edu/wcm/pdfs/1998/wcm98-25.pdf

 

I can't find a straight answer on what we're doing though and I can't really find anything else that supports the fact that root growth is inhibited in higher concentrations of phosphate; this fact is correct though as everyone in my class has come up with these same results and my teacher has confirmed them

[Guest WaterWings]

How about the Controlled, Dependent and independent variables? Also, i'd be interested to know what concentrations people are using and what their predictions are please

[Loului]

Control - no phosphate in the nutrient solution (to prove that is phosphate causing the cells to undergo mitosis and no other external factor)

Dependant (what you are manipulating) - concentration of phosphate

Independant (what you are measuring) - amount of mitosis occuring in the root tips

Surely you can work out a prediction and some concentrations from the preliminary work I outlined in an earlier message? Remember all the work we do actually has to be our own, we're just here to help each other out

[hyebeh]

well... you guys should try reading the entire thread... there was some pretty good things said. Phosphate is used in ATP and in phosphate backbones during DNA synthesis. Thus, phosphate is not only important, it is critical.

[Loului]

0.25 grams is the optimum amount of phosphate for plant growth - if you are given a complete nutrient solution then that is how much calcium dihydrogen phosphate there would be per dm3.

During my preliminary work I grew five cloves of garlic in different phosphate concentrations. I measured the length of the longest root on each clove at several intervals then, after about a week, tested the 'root tip squash' preparation and looked under the microscope at some of the roots. I found that it is around 0.20 grams (from my cloves, these results may be due to the mass of each clove as this variable was not controlled for my preliminary working) of phosphate which encourages more cell division in the root tips. A higher concentration than 0.25 grams did inhibit the growth and I posted scientific knowledge earlier to back this up.

[Guest Leanne_d]

hey. i have just recieved this as my as planning exercise. the stuff on here his reeli useful and think i can understand it now! any ideas on what concentrations wud b good to use? i have a week left so so best get started!

[Guest mccormus256]

wow all this info on this thread is awesome! I recieved my paper yesterday and i am not quite sure how to lay it out. Do we start with a hypothesis? And if any one out there could give me a general, simple explanation of what we actually have to do i wouold relly appreciate it! Oh, another little problem, what happwns if we havn't done preliminary work and our college isn't allowing us time in the lab to do it? Where shall i get the results from, could anyone help me by please giving me their preliminary results! Thanks so much x

ps another thing, what stain are you all going to use because we have been told to investigate a number of different ones as some may interfere with the mitosis, HELP!!!

[Loului]

Hee Hee! I like being a legend, thanks!

(Rakuenso, was that an insult to me? Do you think i'm that sad?)

Anyway... start with the prediction of what you think will happen and back it up with scientific knowledge. You don't really need any preliminary results, you just have to state how your preliminary work helped you decide things you would alter for your final method. I have just found a website that may help people really struggling: http://www.chadevans.co.uk/asite/Alevel/biology/pracfile/prac13.html

In my plan I used acetic orcein, but there is also some blue stain you can use...which I have forgotten the name of - sorry! It should be on your coursework front cover sheet, I handed mine in on tuesday though.

Also, it takes no longer than 48 hours for roots to grow, meaning that mitosis is occuring (anything that grows is undergoing mitosis).

Finally, I don't think anyone has done the OCR practical AS level biology exam yet as it is a board timetabled thing - to prevent cheating such as this.

I really hope this helps, good luck everyone

[Guest mugelwump]

I just wanted to say thanks for the help, even if this is kind of cheating, its helpfull and its not like anyone is giving out the full answers

 

and i'd also like to say the exam thng, as far as i know, isn't untill the 17th for most people. and i dont know about some, but in my college were all put in 'jail' (shoved in a room and not aloud to leave) for the whole day so theres no cheaing, and i think all mobiles will be taken off of people, so i guess it means no cheating, bu being stck in a room for 3 hours before my exam dosen't sound like fun

 

but yeah, thanksagain for the help

[Guest mugelwump]

oh i was doing some research and found this, it might help some people, andits official and so not cheating

 

http://disc.server.com/discussion.cgi?disc=198577;article=363;title=Mark%20Rothery's%20Biology%20Discussion

[Guest Emilywoo]

Hey I'm new to this but this info has been quite useful and I thought I could try and help out too! People were saying they didn't know why excess amounts of phosphate inhibits root growth- basically I think you need to think about water potential. Surely phosphate ions in the solution will decrease its water potential so less will be absorbed by the root tip by osmosis? Correct me if I'm wrong.

[Loului]

Oh yes Emily, water potential...*regrets having already handed coursework in* I knew those teachers were telling us all this stuff beforehand for a reason! Oh well....good luck to everyone else with their plan and also thanks to Angel for creating this board; it helped me too

[Guest mccormus256]

The way i've done it is to start with a hypothesis (prediction of what will happen) and back it up with scientific knowledge from secondary sources, including prem work. Then an equipment list, safety, variables, method, expected otcome and evaluation. Hope that helps

[Guest Emilywoo]

This is how I structured mine:

Aim... Intro... Prediction... Control of variables... Procedure... Diagram of apparatus... Table I would use to record my results... Risk assessment... Criticisms of the procedure.