WebThe diagram below shows the three organisms and some of the calculations the student made. scale: 0.075 mm A B C surface area / mm 2 0.28 3.1 23 volume / mm 3 0.02 0.59 11.3 surface area to volume ratio 14:1 2:1 (a) (i) Calculate the surface area to volume ratio for organism B to the nearest whole number Write your answer in the shaded box in ... WebGas exchange by direct diffusion across surface membranes is efficient for organisms less than 1 mm in diameter. In simple organisms, such as cnidarians and flatworms, every cell in the body is close to the external environment. Their cells are kept moist and gases diffuse quickly via direct diffusion.

Gas Exchange in Insects (A-level Biology) - Study Mind

WebThere are exchange pumps lining the tubules, which actively transport H + ions into the cell and K + or Na + ions out; water passively follows to form urine. The secretion of ions alters the osmotic pressure which draws water, electrolytes, … WebA single-celled organisms does not need specific organs for taking in food, exchange of gases or removal of wastes because the entire surface of the organism is in contact with … field hockey helmet

? Gas Exchange The A Level Biologist - Your Hub

WebNov 26, 2024 · The exchange of substances between the internal and external environments takes place at exchange surfaces. To truly enter or leave an organism, most substances must cross cell plasma membranes. In large multicellular organisms, the immediate environment of cells is some form of tissue fluid. Most cells are too far away from … WebThe complexity of the respiratory system is correlated with the size of the organism. As animal size increases, diffusion distances increase and the ratio of surface area to … WebJan 24, 2024 · Unicellular organisms are exposed to the external environment and require protection which is achieved with diffusion. It is one of the means of transport of … field hockey headbands