Transcript excretion

Excretion
• 1000’s of chemical reactions happen
in every cell
• Each of these reactions will produce
waste products that must be removed
from the body
• Excretion is the name given to this
removal process
The two big ones!
• Carbon dioxide is produced in every cell
large and in large volumes. It is excreted
out through the respiratory system
• Urea is only produced b y one organ,
the liver, but is produced in large amounts
It is the by-product of the breakdown of
excess amino acids; a.k.a DEAMINATION
DEAMINATION
• If more amino acids are taken in than
are required, then they are recycled.
This involves…
1.The removal of the N from the
molecule, to be excreted as Urea
2.Reabsorbing the remainder of the AA
DEAMINATION
In the liver the Amino group (NH2)from the AA is
removed, with an extra H atom.
This creates NH3 or Ammonia.
The remainder of the old AA is know called
a Keto Acid and can become a carbohydrate
and used in respiration.
Ammonia NH3 is very soluble and toxic, so must
be converted immediately to less toxic Urea
This is easily done………Ammonia NH3 + CO2 = Urea
Adults produce 25-30g of urea per day