BIOLOGY COURSEWORK - plez helpWatch
how long to leave them in the oven?? 1hour 2 hours?
how long to keep testing them a week or longer??
where to get background knowledge from??
jesus this is a mission
I know that the dry mass of the seeds decrease because they are respiring, it already basically tells you that in the planning excercise exam sheet. What I still can't figure out is WHY there would be a difference between the two species. This is a very complex practical to be set, too many variables I think. I mean one species may germinate faster than the other because they are genetically different therefore using food reserves faster, also the size of the seed, the size of the seedling AARRRRRRRRGGGGGGHHHH!!!!!!!!
Why would one use food reserves faster?
This is killing me!
You need seeds that will germinate quickly, one of which stores carbohydrate (starch) and the other which stores fat.
Suitable starch-containg seeds would be mung beans or broad beans Suitable fat-containing seeds would be sunflower or castor oil
You will have to 'plant' several batches of (weighed) seeds of each type. You don't need to record the weight of individual seeds, just the weight of the whole batch. At your set times, you should remove any seedling growth from a batch of seeds, and dry them in an oven at about 80°C until they stop losing weight. This final weight is the dry mass.
The following web site has basic information you could include, http://www.seaweed.ie/firstyears/germination.html
I gather (because other people have asked me about this investigation) that the idea is to test two seeds which store different types of food - carbohydrate and fat. You might expect fat stores to be used more slowly than carbohydrate stores because fat contains more energy per gram than carbohydrate. You could perhaps include, in terms of scientific knowledge, how carbohydrate and fat are metabolised in respiration.
To make this a fair, accurate and reliable test, you need to use lots of seeds. I would suggest at least 10 seeds for each time interval you choose. Using a large number improves accuracy of your averages. To make it fair, you need to express the weight loss as % weight loss (i.e. % weight loss is the unit) as the seeds cannot possibly all be the same weight initially.
only other stuff that i can say is that the seeds utilise their energy reserves at different speeds not only because of the way they store their energy, but also there are different methods of germination. Such as epigeal germination and hypogeal germination. You'll need to discuss this in the plan.
hope this helps! good luck everyone!
these r just some random notes below:
light - dark room
soil - inert - pertle / vermilite
water - 5mm3 (just random amount) added each time seeds are removed. use distilited water so less risk of contamination
heat - room temp (20oc)
a destructive method - not putting seeds back in
Early stage ends as soon as photosynthesis begins
both seeds much be dicolyledoneae eg Wheat / broad bean
some 1 help cause i only know some basic stuff
Don't use compost it is just another bloody variable to worry about, use damp cotton wool (no inorganic ion levels etc to worry about etc). I don't see why percent loss of dry weight wouldn't be accurate enough? I was just going to weigh the whole batch and plot graph showing dry mass decrease against time.
you have to do a dry mass measurement (using on oven and scales) every 24hrs are so...to see if all the water has been removed and then you can weigh it to see if the dry mass is increasing or decreasing - decreasing = respiration, increasing = photosynthesis. The RQ values has to do with the substrate inside each cell...ie if the RQ value is above 1 then the cell is mainly carbohydrate, 0.7 = lipid etc. to measure RQ use a respirometer (including soda lime to absorb CO2)
Hope this all kinda mkaes sense? if you want anything else get back to me!
if anyone has anyidea about what might be coming up on the practical exam???THIS TUESDAY??? it should be linked to the planning....respiration? photosynthesis would surely be too hard to investigate under timed conditions??
lipid seed = maize
bit of both = cereals - ie barley, wheat
hope this helps someone along the way!
o - you dont need to worry about % dry mass, remember its just PLANNING! just use the results you get (from preliminary experiment maybe?) and see what happens - you dont nned to say exactly what happens remember?!just suggest!
youll all be fine im sure! just keep smiling!
DONT FORGET A BIBLIOGRAPHY!
does anybody know what apparatus are used?
so testing the affect of concentration on the rate of enzyme reaction methinks?
scales are good for the dry mass and leave it in an oven for 24hrs tis sufficient. then weigh them. then: work ou change in dry mass per day:
but as i sed tis a bit l8 noW! gotta go do it! c u all