Digestion and Absorption Flashcards
Which transport processes do not require energy?
Diffusion and facilitated diffusion
Which transport processes move molecules down their concentration gradient?
Diffusion and facilitated diffusion
Which transport process moves molecules against their concentration gradient?
Active transport
How is the small intestine adapted to aid efficient absorption of digested molecules?
Has villi and microvilli, a large blood supply, thin walls
Which is smaller villi or microvilli?
Microvilli
How do villi and microvilli aid the efficient absorption of digested molecules?
Increases the surface area available for absorption
Define diffusion
The movement of molecules from an area of high concentration to an area of low concentration
Define active transport
The movement of molecules from an area of low concentration to an area of high concentration via a carrier protein. Requires energy
Define facilitated diffusion
The movement of molecules from an area of high concentration to an area of low concentration via channel proteins
How does diffusion differ from facilitated diffusion?
Facilitated diffusion occurs via channel proteins
By what process are glucose/amino acids absorbed into epithelial cells?
Indirect active transport
By what process are glucose/amino acids absorbed into the blood?
Facilitated diffusion
Give an example of co-transport in the absorption of glucose/amino acids
Sodium ions move down their concentration gradient via a channel protein into the epithelial cell, as they do this glucose/amino acids are carried through the membrane too from low concentrations to high concentrations
State 3 ways in which the rate of movement of molecules across membranes can be increased
Increase concentration gradient
Reduce diffusion distance
Increase surface area
Why is the term co-transport used to describe the transport of glucose to cells?
Glucose molecules are carried into cells by sodium ions which move down their concentration gradient through protein carriers in the plasma membrane.
