VCE Biology Question Thread

[Reus]

Pi is an inorganic phosphate

I should have mentioned that^ ><

thank you

so what im getting at is that ATP forms energy when broken down to ADP and Pi, but this ADP and Pi rejoins to form ATP which then breaks down again to make more energy, a never ending cycle? doesn't that mean we would have an endless supply of energy?

im a little confused :/

Pretty much. It's a cycle as you mentioned (can be identified in photosynthesis). However it is not necessarily an endless supply of energy as it is provided through sunlight (light energy) to initiate the reaction (ATP to ADP).

[Kalopsic]

thank you

so what im getting at is that ATP forms energy when broken down to ADP and Pi, but this ADP and Pi rejoins to form ATP which then breaks down again to make more energy, a never ending cycle? doesn't that mean we would have an endless supply of energy?

im a little confused :/

ATP does not form energy. It has energy stored in its bonds therefore when the bond breaks, energy is release and the by product is ADP and Pi. In order for ADP and Pi to form again, energy must be used to bind them together again. You will see this in plants via photosynthesis. So since we need energy to form ATP, we don't have endless energy hence why we need to consume food for energy.

Just an FYI, ATP stands for adenosine triphosphate, ADP stands for adenosine diphosphate and Pi means inorganic phosphate. I'm pretty sure you don't need to know what they stand for

[grannysmith]

^^ ATP is the ' energy currency' of the cell; that is, it's a convenient and immediate source of energy that can easily be transported around the cell.

The formation of ATP from ADP + Pi is an endergonic process. The energy that's required to form such molecules are sourced from cellular processes such as photosynthesis and cellular respiration. For example, aerobic respiration involves the (gradual) breakdown of glucose. This releases energy that is essentially used to synthesise ATP. So why don't we just use the energy released directly from the glucose breakdown? Put simply, that would not be efficient but rather dangerous for the cell.

[bts]

thank you everyone!

so i need energy for photosyntyhesis to form ATP from ADP and Pi, what is needed for the reverse (ATP broken into ADP and Pi)?

[vox nihili]

thank you everyone!

so i need energy for photosyntyhesis to form ATP from ADP and Pi, what is needed for the reverse (ATP broken into ADP and Pi)?

yep, as has been stated, it's cyclic.

[grannysmith]

thank you everyone!

so i need energy for photosyntyhesis to form ATP from ADP and Pi, what is needed for the reverse (ATP broken into ADP and Pi)?

You need ATPase (an enzyme) to break down ATP :p

[plants]

ATP does not form energy. It has energy stored in its bonds therefore when the bond breaks, energy is release and the by product is ADP and Pi.

how exactly do chemical bonds store energy?

[vox nihili]

how exactly do chemical bonds store energy?

You don't need to know. It's a form of chemical energy though, created by the pulling of each atom on each other. Hard to explain without getting too technical.

[cosine]

Which organelles do we need to know their functions of thoroughly? Thanks

[vox nihili]

Which organelles do we need to know their functions of thoroughly? Thanks

Nucleus
Endoplasmic reticulum
Golgi apparatus
Ribosome
Mitochondrion
Chloroplast

[cosine]

Nucleus
Endoplasmic reticulum
Golgi apparatus
Ribosome
Mitochondrion
Chloroplast

Thanks mate!

[Yacoubb]

[quote author=bts link=topic=151609.msg813444#msg813444 date=1423981958in
Hello,
can someone please explain what the Pi is?
Whats the difference between ATP and ADP? are they just different forms of energy one for anaerobic and the other for aerobic or something?

thank you
[/quote]

Something to note is that the bond between the second & third phosphate group in ATP is very energy rich. So, in the hydrolysis of the terminal phosphate group (i.e. Pi), a large amount of energy is released.

[kimmytaaa]

Hi
Just wanted to know what are the key knowledge and points do I need to know for enzymes?
I have an enzyme prac sac tomorrow on liver.

[nhmn0301]

Hi
Just wanted to know what are the key knowledge and points do I need to know for enzymes?
I have an enzyme prac sac tomorrow on liver.

As far as I'm aware, you definitely need to know about enzyme models like: lock and key model and induced fit model. How does enzyme facilitate a reaction? What effects enzyme activities: pH, temperature, concentration of substrates, concentration of enzyme itself etc. Also, make a clear distinction between increasing the rate of the reaction and increasing the amount of products, enzymes wont do the later. Remember to notice the rate of reaction over your set time too.

[kimmytaaa]

As far as I'm aware, you definitely need to know about enzyme models like: lock and key model and induced fit model. How does enzyme facilitate a reaction? What effects enzyme activities: pH, temperature, concentration of substrates, concentration of enzyme itself etc. Also, make a clear distinction between increasing the rate of the reaction and increasing the amount of products, enzymes wont do the later. Remember to notice the rate of reaction over your set time too.

thanks