Movement Of Substances Into And Out Of Cells Flashcards
What is diffusion?
The movement of molecules from a region of higher concentration to a region of lower concentration.
What is the result of random movement of molecules?
This causes the molecules to spread out until they are at an even concentration throughout the available space.
What does diffusion allow living organisms to do?
Gain nutrients in the digestive system.
Gain oxygen in the lungs.
Remove waste products in the lungs and kidneys.
What is osmosis?
The movement of water molecules from a region of higher water concentration to a region of lower water concentration, through a partially permeable membrane.
Osmosis is the diffusion of what?
Water moving down its concentration gradient.
What happens to a plant cell in distilled water (high water concentration)?
The cell gains water, the vacuole expands, and the membrane pushes against the cell wall, making the cell turgid.
What happens to a plant cell in a strong sugar solution (lower water concentration)?
The cell loses water, the vacuole shrinks, and the cell membrane pulls away from the wall, making the cell flaccid or plasmolysed.
What is active transport?
The movement of particles across a cell membrane from a region of lower concentration to a region of a higher concentration.
What is required for active transport and why?
Energy
Because particles are being moved against a concentration gradient.
When is energy released?
During cellular respiration.
What are examples of active transport in cells?
Absorption of the products of digestion into the bloodstream from the lumen of the small intestine
Absorption of mineral ions from the soil into the root hair cells of plants.
What does active transport across the cell membrane involve?
Protein carrier molecules that are embedded in the cell membrane.
What is the rate of diffusion?
A measure of how quickly particles move from one place to another.
Rate of diffusion is increased by what?
A short diffusion distance
A steep concentration gradient
A higher temperature
A large surface area
