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 … 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 ...
Cell models - Gas exchange in animals - Edexcel - BBC Bitesize
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. WebThe gas exchange surfaces are the alveoli. They are very efficient at gas exchange. They provide a large surface area relative to the volume of the body; Gasses dissolve in the surfactant moisture lining the alveoli; The alveoli have walls made of squamous epithelium, only one cell thick, so the diffusion pathway for gases is short highlight navigation bar on current page
39.1 Systems of Gas Exchange - Biology 2e OpenStax
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 … WebAnswer and Explanation: 1. Become a Study.com member to unlock this answer! Create your account. View this answer. A unicellular organism would use just diffusion to allow exchange of gases. Active transport would not be needed. If the organism uses oxygen, the... See full answer below. WebApr 30, 2008 · Gas exchange takes place at a respiratory surface-a boundary between the external environment and the interior of the organism. For unicellular organisms the respiratory surface is governed by ... highlight napoli cremonese