diffusion
Cards (9)
- what is diffusion?net movement of particles from an area of higher concentration to an area of lower concentration
- what are some substances transported in & out of cells by diffusion?
- oxygen
- carbon dioxide
- glucose
- water
- what factors affect the rate of diffusion?
- concentration gradient
- temperature
- surface area
- how are single-celled organisms adapted for diffusion?have a large surface area to volume ratio - maximises rate of diffusion of molecules to meet the organisms needs
- how is the effectiveness of a gas exchange surface increased?
- large surface area
- thin membrane - short diffusion path
- efficient blood supply
- ventilation
- how are the lungs adapted for gas exchange?
- lots of alveoli - large surface area
- alveoli have thin walls - short diffusion pathway
- lungs are ventilated - maintains concentration gradient
- good blood supply - maintains concentration gradient
- how is the small intestine adapted for exchanging substances?
- covered in lots of villi - large surface area
- single layer of surface cells - short diffusion pathway
- good blood supply - maintains concentration gradient
- how are the roots & leaves in plants adapted for exchanging substances?
- lower epidermis covered in stomata - controlled by guard cells
- flat shape of leaf - large surface area
- ventilation - maintains concentration gradient
- how are gills in fish adapted for exchanging substances?
- ventilation - maintains concentration gradient
- each gill is made of lots of thin plates called gill filaments - large surface area
- covered in lamellae - large surface area
- thin surface layer of cells - short diffusion pathway