Homeostasis and Excretion Flashcards
1
Q
Excretion
A
Removal of metabolic waste made by body
2
Q
Functions of Kidneys (2)
A
- Removal of nitrogenous metabolic waste made by body by filtering blood
- Osmoregulation to control water potential of body fluids (regulate water content and solute concentration)
3
Q
Plants (producers)
A
- Take nitrate and ammonium ions from soil by facilitated and active transport for proteins
- NH4+ combine with α-keto glutarate into glutamate (amino acid)
- Glutamate converted to other amino acids by transamination
- Synthesis of amino acids needed so no nitrogenous waste/ excretion
4
Q
What do the Fabaceae family plants have?
A
Mutualistic nitrogen-fixing bacteria
5
Q
Animals
A
- Eat protein and use amino acids to form proteins
- Not efficient at transamination and cannot store excess amino acids
- Deaminated in liver, converted and excreted
6
Q
Deamination
A
- Amino group (+H) removed to form ammonia (NH3)
- Ammonia converted to urea in liver
- Remaining molecule (pyruvic acid) can be used for respiration or converted to fat for storage
7
Q
Ammonia
A
- More toxic, small and more soluble
- Needs to be diluted, so if used, a lot of water would be lost
- Excreted by most aquatic animals in form of NH4+ ions
- Diffuses out across the body surface or gill epithelium
- Diluted immediately as there is lots of water
8
Q
Uric acid
A
- Excreted by birds, insects, reptiles, land snails
- More insoluble in water than others and less toxic
- Very little water needed to excrete it = more water retained/ reabsorbed
- Excreted as precipitate after water reabsorbed
9
Q
Urea
A
- Most terrestrial animals convert ammonia to urea
- Less toxic so can be transported in concentrated form or stored
- Less water needed to discard waste
- Less water lost in urine and more conserved = reduces risk of dehydration
- Helps survival in dry and muddy habitats where water needs to be conserved
10
Q
Advantages of uric acid
A
- Little mass for storage in eggs
- Light (less mass) for flight
- Less water required for disposal = conserve water survive in dry habitats
