solve biology paper 5

[eyamwir]

can anyone help me do this qs. i kind of don't know how to do this -.- even through marking schemes, i don't understand. :s this is from june 2008 question 2 page 6

 

[AAestar]

Just as the question stated, we are to see the effect of carbon dioxide concentration on the rate of photosynthesis. And thus the independent variable is of course the carbon dioxide concentration. Set a range, at least 5 different concentration of carbon dioxide. This can be varied using the carbon dioxide sensor. The dependent variable is the gas produced from photosynthesis of plant. Ensure that the light intensity and the temperature are constant.

Yup, that's about it...hope i helped.

 

[eyamwir]

wow for 8 marks that's just it? thanks btw.

 

[AAestar]

Of course you have to elaborate more..like saying how to maintain the temperature, how to ensure that the light intensity is constant. Mention that it's a low risk experiment and so on...^^ you're welcome~

 

[eyamwir]

how is it possible that you know all these -.- i wasnt taught these in school. the teacher say we study on our own for this paper. -.-

 

[AAestar]

Well, my teacher did teach a little on this. He taught us the most basic way of answering this type of questions and yea, I do further revision by myself. I personally think that tutors should teach p5. Once you know the basic, it would be a tad bit easier...The thing is the same when you're answering this question,


1. Make sure you know the independent variable
2. Dependent variable
3. Control variable, what is to keep constant
4. Perhaps some calculation needed ( optional, depends on the question asked)
5. Risk, Precautions ( perhaps like wear a mask for people who are allergic to pollen when conducting an investigation involving pollen)

Keep the five in mind. Understand the question and I am sure you would do fine.^-^

 

[eyamwir]

i still don't get how to explain the answers can you please give me an example on how to answer this question? sorry. i'm a bit slow. -.-'

 

[AAestar]

This is how I would present my answer. It might not be 100% accurate. Here goes.

Set up the apparatus as shown in the diagram. In this experiment, the concentration of Carbon dioxide supplied would be the independent variable. A carbon dioxide sensor is used to maintain different Carbon dioxide concentration. At least 5 different carbon dioxide concentration should be used. The concentration can be varied using baking powder. The dependent variable is the amount of gas produced in a specific time. To carry out this experiment, ensure that the light intensity and the temperature exposed to plant is constant. The light intensity can be maintained by fixing the distance from the lamp to the pond weed. Temperature can be kept constant using a water bath. Prepare the experiment in a dark room to eliminate the chances of photosynthesizing and cut the weed in the water. Repeat the experiment three time under the same carbon dioxide concentration and get the average. This is a low risk experiment but do be cautious when cutting the pond weed.

Hope this would at least help you a little. I am still learning too ^^!

 

[eyamwir]

ohh, okay now i get. haha thanks a LOT! you're a good teacher!