Video Transcript
Why must urea be removed from the
body? (A) If urea remains in the body, it
can inhibit cell division. (B) If urea is not removed, it can
break down cell walls. (C) If urea is not removed, it will
be stored as fat. (D) If too much urea builds up, it
can be toxic.
Metabolism describes all of the
chemical reactions that occur within living organisms to maintain life. These processes create waste
products that need to be excreted from the body. We can excrete these waste products
using our lungs, skin, kidneys, or liver, for example.
Our kidneys are shown here in red
as these bean-shaped organs. They make and secrete urine, which
is made up of water, ions, uric acid, urea, and other wastes. The bladder is shown below and
stores urine until it’s ready to be removed from the body. So, what is urea? Let’s describe how it is
produced.
As you may recall, proteins are
made up of repeating subunits called amino acids. These proteins can be broken down
into individual amino acids. And these amino acids can be broken
down to be used for energy with ammonia being produced as a byproduct.
Ammonia is toxic, and if it builds
up, this can be very dangerous to our health. So, it is converted into urea in
the liver. Urea is much less toxic than
ammonia, but can still be toxic if it’s allowed to build up. So it is excreted from our body in
urine.
Therefore, the answer to why urea
must be removed from the body is given by answer choice (D). If too much urea builds up, it can
be toxic.
