Bio (cellular respiration)

[ZMir]

hello can somebody help me out here?? in my biology HL class im not understanding the krebs cycle i dont understand how the plant obtains energy like does it only get energy from the sun or are there other factors that contribute to the growth of the plant??
Help me!!
Peace and IB

[almondstone16]

heyy! i'm a bio Hl too...and we just did that topic.
ok what's your prob? you don't get how the plant receives energyy? it' very simple...the only way is sunlight...is THE source of energy. from the sun rays it gets the energy to ( in photosynthesis)
- photoactivation of photosynthesis II ( i think...) which activate the protons in the chlorophyll
- photolysis of water...
and those random procedures that follow after...
i hope it helps, if not, ask me again:D
ps: a good way to revise is teaching people...so help me! hahaha

[xsandralee]

I'm not sure if i'm understanding your question correctly or not, but if you're asking how the plant receives energy, its through sunlight. When sunlight reaches a plant's leaf, the chlorophyll molecules will absorb the light, then begin the process of photosynthesis.

but if you're asking how the plant creates energy through the Kreb's cycle:
After gylcolysis, 2 molecules of acetyl CoA (coenzyme A) are produced. Then, through a cyclic reaciton, it will combine with a 4-Carbon molecule, to form a 6-carbon molecule.
[b]step 1:[/b] when actyl coA comes out of gylcolysis, it combines with a 4-Carbon (4C) molecule called oxaloacetate. Thus, becoming a 6C molecule.
[b]step 2:[/b] During the process in which this 6C carbon becomes Citrate + CoA (which is used again), adp are turned into ATP <- this is where the energy is produced.

overall, after one turn of this kreb cycle, CO2, forms one ATP by substrate level phosphorylation, and gives electrons to 3 NAD+ and one FAD.
-The ATP produced, are usually done through oxidative phosphorylation (when NAD, FADH2 donated electrons)

i hope i have been able to answer your question?