Hi! Thanks for this video. Could you please explain more of the ‘why’ behind increasing temperature resulting in a higher rate of reaction? Also, how exactly is fermentation of glucose for example related to cellular respiration? :)
Hello, Increasing the temperature will increase the rate of reaction, a respiration is an enzyme controlled reaction. Therefore, at high temperatures there is more kinetic energy to ensure successful collisions between the enzyme and substrates, so more enzyme-substrate complexes. Fermentation refers to anaerobic respiration, so cellular respiration when there is not enough oxygen. In animals, this results in the incomplete breakdown of glucose and lactate (or lactic acid in solution) is created.
Hi there. I have a little bit of confusion with the color changes - I saw it from another source where they add Methylene blue instead of TTC, and in that the color changes from blue to colorless. So, if we add TTC the color should change from colorless to red, and if we add methylene blue instead then the color should change from blue to colorless ??
Hello, Great question! Methylene blue is blue when oxidised and turns colourless when reduced. TTC is colourless when oxidised and turns red when reduced. They are both redox indicators. Hope that helps 😊😊
Independent variable is always what you deliberately change (what you are investigating) The dependent variable is what you are measuring (time taken in this case)
No, as NAD would also accept hydrogen, and therefore electrons, to become reduced, which would prevent as much TTC becoming reduced and therefore less TTC would be turning red.
3:20 You said 1 test tube for sugar AND yeast, and another for TTC. so surely thats glucose + yeast with a supply of oxygen in one of the test tubes? i dont get it, if i heard correctly then the yeast + glucose were warming up together in the same test tube in the thermostatic water bath? wouldnt respiration already be taking place in the test tube and so surely hydrogen would already be removed from carbon compounds and NADH even before u added the TTC in? cuz im assuming then the whole experiment is timing how quickly the TTC accepts the hydrogen and not how quickly the hydrogen is removed due to dehydrogenase enzyme?
the rate of respiration isnt going to change significantly over that short period of time of the yeast respiring. as i doubt a large amount of the glucose will be used up so the rate at which hydrogen atoms are being removed and transferred between compounds will remain constant until of course the temp is varied so it doesnt really matter that respiration was occurrring slightly before. also the rate at which ttc accepts hydrogen is proportional to the rate at which enzyme catalyses its reaction so they can be used interchangeably. hence why the ttc changing colour can be used to calculate rate
Hi I was wondering where you found out the information for all the background info, we have to reference it and I don't think I can reference a video! thank you!
Hi! I am using this video and prac as a resource for an assessment task at school. I was just wondering the measurements for the sugar solution and the yeast. Like how much did you add to the test tubes? thanks!
Hello, I don't have the exact volumes, but you can find an example method with that information in the AQA Biology required practical handbook on the AQA webite :)
So glad you like the videos. It is practise as in 'perform (an activity) or exercise (a skill) repeatedly or regularly in order to acquire, improve or maintain proficiency in it.'
