(a)State one function each of the following parts of the nephron:
(i) glomerulus (ii)Bowman’s capsule (iii)proximal convoluted tubule (iv) distal convoluted tubule
(b) Complete the table below.
| Organism | Structure for excretion | Form in which waste is excreted by organism |
| contractile vacuole | ||
| Flatworm | ||
| Earthworm | ||
| Cockroach | ||
| Human | Liquid | |
| Stomata pore |
(c) List five excretory products of plants.
Explanation
Functions of the parts of the nephron
(a)(i)Glomerulus carries out ultrafiltration or it filters the blood passing through it.
(ii)Bowman's capsule receives blood plasma from the glomerulus and filters it to initiate urine formation.
(iii)Proximal convoluted tubule is responsible for reabsorbing most of the glucose, amino acids, and small peptides that enter the ultrafiltrate back into the bloodstream.
(iv)Distal convoluted tubule regulates electrolytes and water balance, and helps maintain pH.
(b)
| Organism | Structure for excretion | Form in which waste is excreted by organism |
| Amoeba/Paramecium | contractile vacuole | Gaseous/Liquid |
| Flatworm | Flame cell | Liquid |
| Earthworm | Nephridium | Liquid |
| Cockroach | Malpighian tubule | Solid |
| Human | Skin/kidney/lung | Liquid |
| Plants(Green) | Stomata pore | Gaseous |
(c) Excretory products of plants include the following:
Carbon dioxide, water vapor, oxygen, resins, gum, tannins, alkaloids, oils, and nitrogenous compounds.