Cell Biology (Section 4) Flashcards
Describe how multicellular organisms have adapted for diffusion, osmosis and active transport
They have specialised exchange surfaces and transport systems
How have animals adapted for efficient exchange? (3 details)
• Highly folded surface of small intestine
• Alveoli in lungs
• Fish have gills
What is the effect of animal adaptations for efficient exchange?
They all increase surface area and maintain concentration gradients
How have plants adapted for efficient exchange? (3 details)
• Roots have highly branched network
• Root Hair Cells increase surface area for absorption
• Leaves have stomata and spongy mesophyll for gas exchange
Surfaces for diffusion, osmosis and active transport have… (3 details)
• Large surface area
• Thin barriers to shorten diffusion paths
• Extensive blood vessel networks to maintain concentration gradient
What is osmosis?
Osmosis is the net (overall) movement of water molecules into the cell across a partially permeable membrane
Osmosis is the diffusion of ____ from a _____ solution to a ______ solution
Osmosis is the diffusion of water from a dilute solution to a concentrated solution
What will water always from from to?
Dilute solution to a more concentrated solution
What does diffusion and osmosis rely on?
The passive transport of substances down concentration gradients
What do cells need to be able to transport?
Substances across the membrane across a concentration gradient
What do cells require to transport substances?
Energy released by respiration
What is active transport?
The movement of substances from a more dilute solution to a more concentrated solution
What does active transport involve?
Protein carrier molecules embedded in the cell membrane
What is a cell?
The most basic unit in an organism
