Bio Topic 13 Flashcards
Where is urea formed?
In the liver
What is urea made from?
Excess amino acids
Which organ excretes carbon dioxide?
The lungs
State three things kidneys excrete
-urea
-excess water
-excess ions (salts)
State three conditions which alter the volume of urine produced
-temperature
-water intake
-excercise
Describe the role of the liver in dealing with excess amino acids
Amino acids are formed from breakdown of proteins during digestion
Amino acids cannot be stored in body (therefore liver converts the ones it can into proteins and the excess needs to be removed)
Deamination creates urea w/ excess amino acids to remove them
What is deamination?
Removal of nitrogen-containing portion of amino-acids to produce urea
Why is excretion necessary?
To remove toxic waste substances like urea and carbon dioxide
Exess urea can be toxic and harm organisms
What is the function of the glomerulus in the kidney?
Blood is at high pressure in glomerulus
Filter out small molecules in the blood (eg. water urea glucose ions)
Large molecules (eg proteins) cannot be filtered out
What is the function of the kidney tubule?
Reabsorbing molecules necessary for the body
What molecules does the kidney tubule reabsorb?
-all glucose (reabsorbed by active transport)
-most of the water
-some of the salts
Describe the last process that takes place in the nephron
Release of wastes:
Liquid left containing urea, excess water & ions is called urine
Urine travels to bladder via ureter
