Exchange Between Organisms and Their Environment

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Flashcards by , created about 6 years ago

AS Biology2 (Exchange and Transport) Flashcards on Exchange Between Organisms and Their Environment, created by sammi_taylor01 on 05/29/2013.

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Created by sammi_taylor01 about 6 years ago
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Question Answer
Give four examples of things that need to be interchanged between an organism and its environment. -respiratory gases -heat -excretory products -nutrients
What two different ways can this exchange occur in (include examples as well) -actively, e.g. active transport which goes against a concentration gradient -passively, e.g. diffusion or osmosis which goes down a concentration gradient.
What two factors affect the amount of each material that needs to be exchanged? -size of an organism -metabolic rate of an organism
What increases the efficiency of how much a substance is exchanged? surface area to volume ratio
Give some examples of features of specialised exchange surfaces. -large surface area to volume ratio -thin diffusion pathway -partially permeable membrane -movement of internal/environmental mediums to maintain a gradient.
Give the equation for working out diffusion. surface are X difference in concentration --------------------------------------------- length of diffusion path
What is a disadvantage of a thin diffusion pathway and how do we overcome it? They are easily damaged, therefore they are often located inside an organism for protection.
What is the surface area to volume ratio like for: 1) small organisms 2) large organisms 1) large surface area to volume ratio 2) small surface area to volume ratio
For organisms with a large surface area to volume ratio, organisms have evolved to have the two following features which help overcome the problem: -a flattened shape so no cell is far from the surface -specialised exchange surfaces with a large surface area (e.g. gills in fish, lungs in mammals)