The Production and Functions of ATP

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The Production and Functions of ATP

The basic process in which ATP is used involves an organic molecule

being phosphorylated by ATP, which produces an organic molecule with a

phosphate group, and reduces ATP to ADP. This phosphorylated molecule

becomes more reactive, thus lowering the activation energy needed for

reactions, mainly used when enzymes are involved. This overview should

demonstrate the importance of ATP- it allows living systems to convert

stored chemical energy to kinetic or heat energy quite efficiently,

resulting in the ability for homeostasis and skeletal movement among

other things.

There are two methods of ATP production, in plants it is a product of

both respiration and the light dependent stage of photosynthesis

whereas in animals it is a result of respiration. Adenosine

triphosphate itself needs energy to be created. It constantly goes

through the cycle of donating a phosphate group and being reduced to

Adenosine diphosphate, and then being phosphorylated back to ATP. The

energy for the formation of ATP in animals is derived from respiration

in which theoretically thirty eight ATP molecules can be restored when

the chemical bonds in a single mole of glucose are broken.

Aerobic respiration commences with the process of glycolysis

(literally: sugar splitting). This process takes place in the cytosol

in the cytoplasm of the cell whereas the remaining processes occur in

the mitochondrial matrices. Two ATP molecules each donate a phosphate

group to a glucose molecule which lowers the activation energy for its

break down into two pyruvate molecules. The intermediate step is where

glucose with the addition of t...

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...actin group, and upon

bonding the tertiary structure of the myosin head changes, causing the

rest of the myosin to move along to accommodate the change in

structure. The reaction between the actin and myosin now causes the

head to release the ADP and Pi which is taken up by a mitochondrion.

In the processes outlined above, this is converted to ATP via

respiration, and ATP is released back into the muscle tissue. This ATP

is needed by the actin-myosin bridge to be released. ATP diffuses into

the myosin head, and the donation of a phosphate group to the bond

lowers the activation energy, allowing the head to be released. It

resumes its original tertiary structure and is available to bridge

with another myosin further down the fibre. This process occurs over

and over again, making the overall contraction a ratchet motion.

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