Theory question 101
ExcretionSection A
(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:
Table columns: Organism | Structure for excretion | Form in which waste is excreted by organism
Rows: ______ | Contractile vacuole | ______
Flatworm | ______ | ______
Earthworm | ______ | ______
Cockroach | ______ | ______
Human | ______ | Liquid
______ | Stomatal pore | ______
(c) List five excretory products of plants.
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(a)(i) Glomerulus: ultrafiltration of blood under high pressure.
(ii) Bowman's capsule: collects the glomerular filtrate and passes it into the tubule.
(iii) Proximal convoluted tubule: selective reabsorption of glucose, amino acids, salts, vitamins and much water.
(iv) Distal convoluted tubule: reabsorbs more water and salts (osmoregulation) and secretes some ions (e.g. H+, K+) into the urine.
(b) Amoeba/Paramecium - contractile vacuole - liquid (and gases by diffusion);
Flatworm - flame cells - liquid;
Earthworm - nephridia - liquid;
Cockroach - Malpighian tubules - solid (uric acid);
Human - kidney (also skin, lungs) - liquid (urine);
Green plant - stomatal pore - gas (carbon (IV) oxide, oxygen, water vapour).
(c) Any five: oxygen; carbon (IV) oxide; water; tannins; resins; gums; latex; alkaloids (e.g. quinine, caffeine, nicotine, morphine); oxalic acid / calcium oxalate crystals; anthocyanins.
In (b), fill every blank: the organism, its excretory structure and the state of its waste.