The Cell Membrane
What term describes a membrane that only lets certain substances pass through?
Selectively permeable
In diffusion, particles move from areas of _____ to _____ concentration.
High to low
What is osmosis specifically the movement of?
Water
Where does the eye get oxygen from?
From the atmosphere by diffusion.
What does "passive transport" mean?
Movement of substances without energy.
What part of the cell controls what enters and exits?
The cell membrane
What is the term for a balanced concentration on both sides of a membrane?
Equilibrium
What direction does water move in osmosis?
From high to low water concentration
Which organ absorbs nutrients using diffusion?
The small intestine
What word means the spreading out of particles until they’re evenly spaced?
Diffusion
Does diffusion through the membrane require energy?
No, it is passive
Why does diffusion require no energy?
It happens naturally due to particle motion
What happens to a plant cell when it’s placed in pure water?
Water enters the cell and it swells
What happens in the lungs due to diffusion?
Oxygen enters blood, CO₂ exits.
What structure surrounds the cell and maintains balance?
The cell membrane
What does the membrane block out?
Larger molecules like sugar and protein
Which gas diffuses into the eye from the atmosphere?
Oxygen (O₂)
What happens to animal cells when too much water enters by osmosis?
They can burst or lyse.
What organ uses osmosis to balance water and waste?
The kidney
What causes particles to naturally move from high to low concentration?
Random particle motion.
What kind of molecules pass easily through the membrane in osmosis?
Water molecules
What process allows CO₂ to exit the body through the lungs?
Diffusion
Why is osmosis important for cells?
It helps maintain balance by controlling water movement in and out.
What happens if you place a raisin in water overnight?
It swells as water enters by osmosis.
What two processes help substances pass through membranes without energy?
Diffusion and osmosis