A Level Biology Revision "The Link Reaction"

You can find all my A Level Biology videos fully indexed at www.freesciencelessons.co.uk/...
In this video, we look at the link reaction. First we explore what takes place during the link reaction and how many molecules we make of the products acetyl coenzyme A, reduced NAD and carbon dioxide. Finally, we explore why the link reaction is an example of oxidative decarboxylation.

[@ihateluke771]

thank you for your a level videos they have helped me so much especially because my teachers have been absent

[@nlonal]

Good day to you, Mr Donnelly,
First of all, I would like to thank you. I have achieved 9,9,8 in my science GCSEs in no small part due to you. Moving forward, I do have one question - how much of A-level biology and chemistry have you covered?

[@Freesciencelessons]

Thanks for the comment and I'm glad that my videos helped you. I have covered 50% of the A level biology and chemistry courses (essentially the year 12 material) and am now moving on the year 13 content.

[@mangoking9767]

Mr Donnelly on top🔛🔝🔥🔥🙌🙌

[@FelipeSonzini]

youre honestly a life saver bud, keep it up :D

[@user-uq3gk3jg7e]

Will you be making Physics a level content?

[@ritzyme4958]

When will you be doing A level physics?

[@ummehabibasalahuddin4090]

i was taught in school that glycerate phosphate is formed after triose phosphate which then converts into pyruvate? can u plz clarify what that is

[@ashe4643]

Hey I have a question,
Where does the hydrogen ion come from which the NAD accepts?
Thanks so much for the video!

[@Freesciencelessons]

Thanks for the comment. Hydrogen ions are quite common in cells and organelles. That's because water molecules naturally split, forming hydrogen ions.

[@ashe4643]

@@Freesciencelessons Thank- you so much!

[@bonniexwony]

thanks for the video sir :D but i have a question .. what is NAD and coenzyme A ? or is that out of syllabus ?

[@Freesciencelessons]

Hi. Everything you need to know is in this video: ua-cam.com/video/1Y4R-yD337g/v-deo.html

[@rubiksworld2170]

You’ll need to know both for a level respiration. NAD is a hydrogen carrier used in respiration, as well as FAD (another hydrogen carrier)

[@Raziel537]

At 3:55 you say the link reaction does not require oxygen, why do we consider it aerobic then?

[@Freesciencelessons]

Because in order for aerobic respiration to take place, the pyruvate must pass through the link reaction. You'll find that the next stage of respiration (the Krebs cycle) also does not require oxygen.

[@Raziel537]

@@Freesciencelessons I see, thank you.

[@Diorfitzz]

@@Freesciencelessonsbut the link reaction and glycolysis don’t require oxygen, doesn’t make it anaerobic?

[@Freesciencelessons]

Both glycolysis and the link reaction are part of the overall process of aerobic respiration, even though neither of those processes require oxygen. Glycolysis is also part of anaerobic respiration if oxygen is not available.

[@Diorfitzz]

@@Freesciencelessons thank you sir! have you done any videos on neurons for a level yet?

[@vzilqz3555]

my man

[@fruit3]

sir isnt NAD to reduced NAD reduction?

[@Freesciencelessons]

Hi yes that's correct. When I say an oxidation reaction takes place, I mean that the reactant molecule (essentially the pyruvate) is oxidised. The hydrogen and electrons which are removed are then added to NAD to form reduced NAD.

[@yousefsalim5468]

Nad to reduced Nad isnt that reduction not oxidation???

[@Freesciencelessons]

What happens is that an oxidation reaction takes place during the link reaction and this leads to reduced NAD being formed (ie the NAD is acting as an oxidising agent ).