IGCSE Biology (0610) - 0610/62/F/M/26 | Feb/March 2026 Paper 62 (Extended)

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[00:00:00]Hey guys, welcome back to a new video by biology resumption. So today we are going to do the Cambridge IGCSC biology paper 6 alternative to practical the 0610 uh February March 2026 uh paper 6 and variant 2. Now uh like any paper six that we have done uh just make sure that um you're writing again in full sentences and in paragraphs uh try not to write to any point forms in exams so that uh we are making sure that reckoning academic response and if you have any questions relating to this paper you can comment down in the comment section below. I've attached the PDF of the paper with the annotated one also in the description box. All right.

[00:00:44]So let's start off with the very first question. Now the first question uh gives you actually a really classical question or not on the catalyst is an enzyme that catalyzes the breakdown of hydrogen peroxide to form water and oxygen. Now catalyst is found in the potato tissue. The oxygen produced during the breakdown of hydrogen peroxide forms a foam. The hydro foam can be used to measure the activity of the catalace. A student investigated how the surface area of the potato tissue affects the activity of the catalase.

[00:01:12]And the student was provided with three cubes of potato tissue. Each cube was 1 cm * 1 cm 1 cm * 1 cm in the size as shown in figure 1.1. The total surface of the each cube of the potato was 6 cm squared.

[00:01:27]All right. Now from the first few sentence itself we can already identify what is actually the independent variable and what is actually the dependent variable. So if you can just see here is that the surface area of the potato tissue would be the actually the independent variable because it says how is affecting the activity of the catalace and the dependent variable is something that you can measure. So the thing that they have already substitute to measure the activity of the catalase and that is the height of the foam. So these two u variables have already indicate to you that these are the independent variable and the dependent variable. Now the student uses this method. Label three test tube 1 2 and 8.

[00:02:08]Put 10 cm cube of hydrogen peroxide solution into each of the test tube.

[00:02:12]Making sure that this is actually the same uh volume and the same concentration of the hydrogen peroxide.

[00:02:17]Now put one of the cubes of the potato in the test tube and then remaining cubes of the potato onto the white towel and use the ruler or the scalpel to measure and cut the cube or potato as shown in figure 1.2. This will make two equalized pieces and the total surface area for this is two pieces is 8 cm square. Now they've already cut this and then now it become splits of 0.5 to 0.5 cm. So they have again uh put the remaining cube of the potato and cut again and this will make eight equal size cubes. A part one calculate the total surface area of eight cubes of potato made in step six. Okay. So what you can see here is they want you to measure what is the um the total surface area of the cubes that have been made in the in the step six itself. So you have to use 0.5 okay 0.5 and multiply by 0.5 because you got 0.5 here and then you got 0.5 here. Now you also have another 0.25 which is actually indicated here because when you split because you're counting towards one cube itself right this here is 0.25. So 0.5 * 0.5 you're getting uh 0.25 cm squared.

[00:03:39]Now 0.25 25 cm square. You have to multiply by um by 0.25 because 1 cube of this is actually the half of 0.5 cm. Now when you have multiplied that you're going to get 1.5 cm squared and as you can see here there are eight cubes 1 2 3 4 5 6 and then behind there behind these two there will be two more. So there will be eight. So 8 * 1.5 = to 12 cm squared. So that is actually the uh answer for this. It's a bit of your mathematics I would say. Now step seven, put the eight cubes of potato into test tube eight. Start the stop clock and wait for 5 minutes and after 5 minutes place the ruler against the outside of the test tube one. Measure the distance from the top of the liquid and the top of the foam. Record the measurement and repeat step nine using test tube 2 and eight. Now they've given you these test tubes. Now at the end of the investigation prepare a table and record the students results. So uh this is actually how my table has looked. The surface area of the potato tissue plus is centime square and the height of the foam is per mm. Now you have to just put in all the data again because I do not have the official mark scheme. Thus the values here could be incorrect but this is generally what I have measured which is tested. 1 is at 6 cm square and the form is 9 mm and 2 is at 8 when it is at 23 and then here 8 is at 12 and 29.

[00:05:08]Okay, so uh generally these are the answers. So just make sure to uh check your answers before you uh proceed to the uh next question making sure that you times 10 because like uh I want this to be in m okay now state the conclusion for these results. So the conclusion for this is that you use the IV and compare it with the DV. So as the surface area of the potato tissue increase it becomes becomes greater here. So you can see the greater the surface area actually then the foam height of the foam becomes higher. So the height of the foam increase. Now state two variables that were kept constant in this investigation. So I mentioned it was the volume of hydrogen peroxide and also the concentration of the hydrogen peroxide.

[00:05:53]You can also give that the total mass or the total volume of potato has to be the same and also the same time interval of 5 minutes. It's also some of the variables that you should kept the same.

[00:06:04]Now identify one safety hazard in this investigation. So of course you are cutting the potato, right? So you we're going to use a scalpel or you can use maybe you can say use a small knife and that has to cause injury. So making sure that you cut always away from the uh of the away from you. Now part six identify two possible sources of error present in this investigation. Now suggest an improvement for each of the errors that you have identified. So you can let me know what are your errors but so far uh these are the ones I can find. The first error is difficult to measure the exact top of the foam because you can see the foam is actually very uneven right see it's like this and it's like this and then there's like go up and goes down.

[00:06:46]So it is very uneven. So how are you going to make sure that you're going to measure it the right way? So you can substitute the way how you measure gas in using a gas syringe instead. Uh the second one I've used is that some of the oxygen could have escaped or the foam could have reduced because you know it's open air right? So thus you can use a lid to cover the test tube. So generally this is the two things that I can uh figure out but if you have more I can help you check to check and maybe we can learn a thing or two from here. Okay.

[00:07:15]Part B. Iodine solution can be used to show that potato tissue contains starch.

[00:07:19]State the result of the positive test with iodine solution. So this is very straightforward. Blue black. Okay. Now part C. A student investigated the in effect of copper sulfate concentration on the activity of catalase in potato tissue. When small disc of potato are dropped into the hydrogen peroxide solution. They sink. The catalyst in the potato tissue breaks down the hydrogen peroxide solution producing bubbles of oxygen. The bubbles of oxygen cling to the disc of potatoes causing the disc of potato to rise back up to the surface of the hydrogen peroxide solution. The student places the small disc of potato in different concentration of copper sulfate solution and leaves them to soak in 10 minutes. Drop the drops the soaked disc of the potato into the hydrogen peroxide solution and you now you measure the time taken for the disc of potato to reach the surface of the hydrogen peroxide solution. Now uh it's very clear that they already given you what is the dependent variable and independent variable. So uh the independent variable will be the different concentration of the copper sulfate solution and and they also tell you what's a dependent variable which is to measure the time taken for this potato to reach the surface of the hydrogen peroxide solution. Just put these two answers into your first question which asking you to state the dependent and the independent variable in this investigation which are these two main points. Now part two suggest a suitable control experiment for this investigation. So you can see that they've been using a hydrogen peroxide pretty much everywhere. Sorry, I mean they've been using copper sulfate solution as their main independent variable. So to see whether there are any changes or to to have a control you can basically use distilled water instead of copper sulfate solution to kind of see that you know that copper sulfate solution is actually the one making the changes or it is there to have changes in the experiment.

[00:09:06]Okay. Part three, table 1.1 shows the results of the investigation. Now there's a concentration of copper sulfate solution per mole per dm cube and the time taken for this of potato to rise. So clearly here is this the IV and concentration of copper sulfate solution and the y-axis is the time taken for this potato to rise. So you have to make sure that this is how the graph would look like and they ask you to plot a line graph. So you just have to draw a straight line and making sure that your graph actually covers more than 50% of the uh of this graph paper here. So your x-axis, make sure you label your xaxis here with the with the units per per dm cube and you put your your points at 0.00.005 and then you plot it out y-axis. Make sure to have your labelings and the correct suitable uh you know space outs and then you just draw your graph. So it should look like this. Very nice linear line graph. So the next question will definitely be asking you to use your graph to estimate the concentration of the copper surface solution when the disposito 80 seconds to write. So you just find 80 seconds which I discovered here and you can see it's around 0.006 just nice is right there. Okay. All right. Question 2 a. So I can see it's a drawing question. So figure 2.1 is a photograph of a fruit from a chili pepper capsicum annuorm. The chili pepper fruit has been cut into half. So you just basically have to draw. I know it's not a very nice drawing, but just something to take note when you are drawing anything is to make sure that you have a single clear unbroken line with no shading. Your drawing occupies at least half of the space provided larger than the original photograph.

[00:10:42]making sure you have the correct shape of the outer per cup or the flash of the chili and making sure the seats the number of seats are correctly positioned and also the way how it's attached all right to the central itself. So these are the common things that you should get and making sure that you don't have any unbroken lines and no shading in your drawing. Okay, the next question line PQ on figure 2.1 represents the length of the chili pepper fruit.

[00:11:07]Measure the length of line PQ. I measured around 89 on using my iPad. You may measure it differently on your physical paper. So when you divide it 89 divided by the uh magnification which is 1.7 1.7 you can get it from the question here. So that leaves you 52.4 mm. All right because the questions give asking you to give in mm and then three significant figures only.

[00:11:35]Okay. B chili pepper fruits. Okay. They contain reducing sugar and non-reducing sugar. Now they have asked you to the student test a sample of chili pepper fruits with the Benedict solution to show what they contain reduced that they contain reducing sugar. Now state the result the positive test. So a break rate precipitate will be sufficient. Now the next question is asking you for the sugar content the chili pepper fruit increases as the fruit ripens and they given you that 96 kg in unripe and ripe that's 36.1 kg and they ask you to calculate the percentage increase. So final value minus initial value divide by initial and that you times by 100. So you should be getting 84.18% and that will be your final answer making sure it's at two decimal places.

[00:12:21]Okay. The very last question is planning investigation to determine the effect of wind speed on the rate of transpiration.

[00:12:28]So I've given I given in this sort of like line by line but in exam try to write in paragraphs and try to uh use these few points that I can suggest to you. You can definitely share uh your points also uh so that we can see evaluate the different v the varied response for this question. So for my independent variable I've mentioned to use different speed settings on the fan with either using a low medium high preset. So you could either use a uh changing the wind speed also by making the the fan uh place in three different distances. One very short and state the actual distance and one is at u a bit slightly a bit far away and one is really far away. So you can also use that but I have chosen to use different speed settings. Okay. And for the dependent variable I because I see related to transpiration I could use a photometer or some of you guys may want to use um or to measure the time taken using a stopwatch but it's better to use a photometer for this because uh for transpiration it's easier to see the maniscus to see how much it has traveled. So I have mentioned to measure the distance moved by the air bubble or the meniscus in the photometer. Right.

[00:13:36]You can also do the alternative or measure the time taken using a stopwatch to calculate a rate which is the distance of the meniscus that move per minute. The constant variable making sure that you keep the temp temperature the same uh keeping the same distance or the same light intensity of of the lamp when you are trying to maintain light intensity. You can use the same plant species making sure the humidity is maintained by making sure the plants are placed in the same room. Okay. and making sure you're using the same sp plant plant species, same number of leaves, same surface area of the leaf.

[00:14:08]All right, so these are the things that you need to try to make it constant. The method well I've already mentioned to you that you're going to use a phototer to measure the water uptake or you may want to use a balance or to measure how much of water has been lost from transpiration initial or after. All right. There's many different ways you can do that, but I've chosen to use the photometer because like transpiration is quite easily uh it's quite accurate using the phototer to actually measure, but you can always use the initial mass and final mass method to definitely do this investigation. And lastly, uh you can definitely um be using the safety by making sure that you cut the plant tissue away from the body when using the knife. and I miss out one very important thing is making sure you repeat this investigation more than two or three times. All right, so to make sure that um you know there are no anomalies that can be identified two or three or more times. Okay, so actually that's all for this paper six. I wasn't expecting to be just like that but well it is. So, if you have any questions, uh you can always feel free to comment down the comment section below. And if you have your exam soon, all the best and hope to see you in the next one. Bye-bye.