Role of ATP


HideShow resource information
  • Created by: flower123
  • Created on: 17-04-12 11:04
Preview of Role of ATP

First 487 words of the document:

The role of ATP
ATP stands for Adenosine triphosphate, a complex molecule that contains the nucleotide
adenosine and a tail consisting of three phosphates. ATP is produced by all living organism in
their cell's organelle mitochondria. ATP is the immediate source of energy that drives most
cellular work for example muscle contraction, active transport etc. Energy is released by
hydrolysis of the third phosphate group. When the third
phosphate is released, the ATP changes to ADP
(adenosine diphosphate) releasing small energy. ADP can
absorb energy and regain the group of phosphate
therefore it regenerates an ATP molecule which can store
ATP + H2O <=> ADP + inorganic phosphate (Pi)
This is the process by which all living things gain energy. There are about four stages in
respiration. The steps of the process allow small amounts of energy to be released at each step.
In respiration food molecules like glucose are oxidised into carbon dioxide and water.
C6H12O6 + 6O2 + 6H2O 12H2O + 6 CO2
Some energy is also released which is trapped in the form of ATP which can be used by all
other cells. In the first stage of respiration, glycolysis, 2 ATP molecules are used and this stage
produces 8 ATP. Glycolysis takes place in the cytoplasm of the cells and activates glucose by
adding two phosphate groups from the two molecules of ATP. This makes a molecule called
phosphorylated glucose. This molecule is then split into two molecules known as triose
phosphate. In this stage triose phosphate is made by oxidising the phosphorylated glucose
molecule. The hydrogen removed here is transferred to a carrier called NAD. In the final stage
pyruvate molecules are produced. In this stage two ATP molecules are formed.
Most of the life on the earth depends on photosynthesis. Only 2% of the suns energy is used in
photosynthesis. Photosynthesis has two parts:
1. The light dependent reactions = this takes place in the thylakoid part of the
chloroplast. This reaction provides ATP and NADPH to the light ­ independent
2. The light ­ independent reactions = this takes place in the stroma of the chloroplast.
His process is also known as the Calvin cycle. In this process carbon dioxide enters the
stroma via the stomata. The carbon dioxide combines with each of the three ribulose
bisphosphate (RuBP) which is 5carbon sugar. Two molecules of glycerate 3 ­
phosphate (GP) from each of the RuBP therefore at the end 6 GP are made. 6 ATP
and 6 NADPH are spent in order to phosphorylate each of the glycerate 3 ­ phosphate
and 1, 3 ­ bisphosphoglycerate is produced. Out of the 6 1, 3 ­ bisphosphoglycerate, 5
remain in the Calvin cycle and only 1 is used to make sugar (glucose). The rest of the 1,
3 ­ bisphosphoglycerate rearrange back into 3 RuBP which requires 3 ATP

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

Doing work requires energy and muscles do a lot of work which is why muscle contraction
needs energy which comes from the ATP. However only little amount of ATP is stored in the
muscles which are used up with just a few contractions. There is another phosphate compound
stored in the muscle called creatine phosphate. This compound is formed by a phosphate linking
to the substance creatine. Creatine phosphate cannot be used directly however it can transfer
the phosphate group to ADP to form ATP.…read more


No comments have yet been made

Similar Biology resources:

See all Biology resources »See all resources »