3.1 Specialised Exchange Surfaces Flashcards Preview

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Flashcards in 3.1 Specialised Exchange Surfaces Deck (11):

All organisms need to do what?

Exchange with their environment


All cells need to take in what?

Oxygen and glucose for aerobic respiration and other metabolic processes


Cells also need to excrete what?

Waste products like carbon dioxide and urea


The smaller an organism the greater it's what?

Surface area to volume ratio


The greater the surface area to volume ratio the greater the efficiency of what?

Diffusion of gases


Why do unicellular organisms not need specialised exchange surfaces?

Substances can diffuse directly in or out of their cell surface membrane
Small diffusion distance
Large sa:v


In multicellular organisms why is diffusion across the outer membrane too slow?

Large diffusion distance
Small sa:v
High metabolic rate - need constant supply of glucose and O2


What do multicellular organisms need?

Specialised exchange surfaces
E.g. Alveoli in lungs


What are the features of an efficient exchange surface?

Large surface area
Thin surface
Concentration gradient (blood supply/ventilation)
Moist surface


Why do most multicellular organisms respire aerobically?

Higher energy requirements and aerobic provides 19x more ATP than anaerobic


Give an example of a exchange surface with large sa:

Root hairs
Gives roots large sa increasing water absorption and mineral ions

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