A2 Biology - help please

[extremeranger]

Energy and Respiration

Sources on internet say that ONE GLUCOSE MOLECULE produces 38 ATP MOLECULES. Wouldn't that be wrong as during the glycolysis stage, a glucose molecule is split into TWO PYRUVATE MOLECULES and as we see, only ONE PYRUVATE MOLECULE moves on to further steps of respiration. Hence, that would mean that only HALF of a glucose molecule produced 38 ATP molecules? If I'm wrong, please explain why.

 

[AAestar]

In glycolysis, two molecules of pyruvate are formed, accompanied by the formation of 2 ATP each...meaning there would be a total of 4 ATP as the end product. However, 2 ATP molecules are used as activation energy in glycolysis and so there's only a total of 2 unused ATP. In Krebs cycle, each pyruvate produces 1 ATP molecules. Since there are two pyruvates, a total of 2 ATP are produced. In Electron transport chain, reduced NAD and FAD from the other stages will accumulate here to liberate the proton. A total of ten reduced Nad and two reduced FAD enter the electron transport chain. Therefore, there is a total of 34 molecules made in electron transport chain. Add the numbers of ATP molecules up and you will get 38.

ONE GLUCOSE MOLECULE produces 38 ATP MOLECULES. Wouldn't that be wrong as during the glycolysis stage, a glucose molecule is split into TWO PYRUVATE MOLECULES and as we see, only ONE PYRUVATE MOLECULE moves on to further steps of respiration. Hence, that would mean that only HALF of a glucose molecule produced 38 ATP molecules? If I'm wrong, please explain why.

Both pyruvate molecules are needed.


Hope I helped ^^!

 

[extremeranger]

Thanks!

 

[madan159]

I am confused in Isolated mechanism of evolution of species.Would anyone clearly explain this mechanism.

 

[AAestar]

Isolating mechanism prevents the breeding between populations and which can eventually lead to speciation ( formation of new species). There are two types of speciation, allopatric and sympatric. Allopatric also known as geographical isolation, happens when any physical barrier like mountains and oceans prevent members of different demes from meeting and interbreeding. Sympatric make use of other reproductive isolation mechanism to ensure that members of separate population are not able to interbreed eventhough they are in the same geographical area.

That's the summarised part. I am not sure where you need help in, as in the whole part or just a small part. So I've laid out the summarised part so tell me which part you need an explanation. ^^

Hope I help.

 

[madan159]

polyploidy comes under sympatric speciation.This occurs due to the error occuring during meiosis process.As a result polyploid organism is formed.It is sterile.When two tetraploid gametes is mated the fertile organism is formed.Tetraploid and original diploid arganism are then taken as two different species.
If i was wrong make me clear about polyploidy.

 

[AAestar]

polyploidy comes under sympatric speciation.This occurs due to the error occuring during meiosis process.As a result polyploid organism is formed.It is sterile.When two tetraploid gametes is mated the fertile organism is formed.Tetraploid and original diploid arganism are then taken as two different species.
If i was wrong make me clear about polyploidy.

I am not sure but I think this polyploidy thing is under Reduced Hybrid Fertility, one of the type of sympatric speciation. If chromosome of the two parent species differ in number or structure, meiosis in the hybrids may fail to produce normal gametes. Since the infertile hybrids cannot produce offspring when they mate with either parental species, genes cannot flow freely between the species.

A very good example would be the hybrid offspring of a donkey and a horse, a mule is robust but sterile.

Meaning if the chromosome are similar anatomically, then yes, they would produce fertile offspring.

 

[rvelzahid]

ATP = 32 at the end...

 

[hassam]

 

[AAestar]

According to biology textbook by Phil Bradfield, the total number of molecules made per glucose molecule can be either 38 or 36. The total number would be 38 if there are 6 NADH produced from glycolysis, 36 when there are 4 produced in glycolysis. ^^ 34 is also an acceptable answer. I am sticking to 34 ATP molecules though, that's what my tutor told me to do.

 

[extremeranger]

Another question:
In Photosynthesis, what determines if Cyclic or Non-cyclic phosphorylation is going to occur?
Also, when Cyclic phosphorylation occurs, no reduced NADP is produced. As calvin cycle requires reduced NADPH, how would it continue if there's no reduced NADP?

 

[AAestar]

From what I know,both occurs at the same time.

can't find a decent photo online...= =



Photosystem I emits 2 electrons and one is used to combine with hydrogen ions and NADP to form reduced NADP. Another electron is used in the cyclic photophosphorylation.

 

[hassam]

 

[madan159]

would someone explain about sex linkage

 

[hassam]

An athlete sprinted for 100 m. This intense activity used anaerobic respiration. Describe and explain what would happen to the athlete’s RQ value?
in MS its mentioned "ref to residual aerobic respiration ;" wat does this mean ?

 

[OakMoon!]

would someone explain about sex linkage

Sex linkage is the inheritance of traits via the X or Y chromosome, i.e. sex chromosomes. An example is the disease color blindness, since the genes for this disease resides on the sex chromosomes, the inheritence of this disease is called sex linked.

 

[AAestar]

An athlete sprinted for 100 m. This intense activity used anaerobic respiration. Describe and explain what would happen to the athlete’s RQ value?
in MS its mentioned "ref to residual aerobic respiration ;" wat does this mean ?

Sorry but may I ask what paper are you taking?

 

[hassam]

p4 and p5

 

[hassam]

p4 and p5

 

[AAestar]

Oh...I haven't heard of 'residual anaerobic respiration'...sorry I cant help you with that...I am waiting for others to reply too.