kidneys Flashcards
(66 cards)
how do plants take up nitrates and ammonium from the soil
facilitated diffusion and active transport
do plants excrete nitrogen-containing molecules?
no (only synthesise amino acids they need)
where are excess amino acids deaminated? what happens to the other molecules it is converted into?
the liver, they are excreted
do animals excrete nitrogen-containing molecules?
yes
what is deamination? and where does it take place?
removal of the amino group, which leaves NH3 and pyruvic acid, the liver
what happens to the ammonia in the liver
converted to urea
what can pyruvic acid be used for
for respiration as a source of energy or converted into fat and stored
draw an amino acid
H2 - N - CH(R) - C=O-OH
what type of animals excrete ammonia
aquatic animals
give 3 properties of ammonia molecules
small, very toxic, soluble
what occurs in soft-bodied invertebrates (to do with ammonia)
ammonia diffuses across the whole body surface into the surrounding water
what occurs in freshwater fish (to do with ammonia)
most of the ammonia is lost as ammonium ions across the epithelium of the gills
which animals excrete uric acid
snails, insects, birds and some reptiles
give 2 properties of uric acid
insoluble in water, non-toxic
how is urea excreted from the body
as urine
why can urea be transported in much higher concentrated form than ammonia
it is much less toxic (100,000x less)
what would the effect of not having urea breaking down ammonia
an animal would have to urinate in large amounts (ammonia is so toxic it can only be transported and excreted in a very dilute solution
what advantages does uric acid have over ammonia/urea
less toxic and reduces water loss (therefore need for water)
which macromolecules are broken down to produce nitrogen containing waste
proteins and nucleic acids
which artery/vein does each kidney receive blood from
renal artery
where does each kidney return blood to (via what)
to the vena cava via the renal vein
what does the renal cortex contain
bowman’s capsules / glomeruli (ultrafiltration)
what does the renal medulla contain
loops of Henle and collecting ducts
what does the renal pelvis do
empties urine into the ureter
