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
In multicellular organisms why is diffusion across the outer membrane too slow?
Large diffusion distance
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
Concentration gradient (blood supply/ventilation)
Why do most multicellular organisms respire aerobically?
Higher energy requirements and aerobic provides 19x more ATP than anaerobic