chapter 3: movement into and out of cells Flashcards
(22 cards)
What is diffusion?
Net movement of particles down the concentration gradient (high → low) as a result of their random movement.
What is the energy source for diffusion?
The kinetic energy of the random movement of molecules and ions.
What happens to concentrations of molecules at equilibrium?
The concentrations of molecules are equal.
Why is diffusion important for life?
It allows molecules like glucose and oxygen to reach required places for processes such as respiration.
What factors influence diffusion?
- Concentration gradient
- Temperature
- Surface area to volume ratio
- Distance
What is osmosis?
Net movement of water molecules from a region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution) through a partially permeable membrane.
What role does water play in organisms?
Acts as a solvent to aid with digestion, excretion, and transport.
What is the condition of a cell when the concentration of solute inside is low and outside is high?
Cell shrinks (flaccid/hypertonic).
What occurs to a plant cell when it becomes turgid?
The vacuole fills up, and the cell wall withstands the higher turgor pressure.
What is plasmolysis?
The process in which a plant cell loses water due to osmosis, causing the cell membrane to shrink away from the cell wall.
What is dialysis tubing?
A non-living, partially permeable membrane made from cellulose.
What can pass through dialysis tubing?
- Glucose
- Water
What is active transport?
Movement of particles through a cell membrane from a lower concentration region to a higher concentration region (against a concentration gradient) using energy from respiration (ATP).
What role do carrier proteins play in active transport?
They pick up specific molecules and move them through the membrane against their concentration gradient.
What is the purpose of active transport in organisms?
To optimize the nutrients an organism can take up, such as ion uptake by root hair cells.
What is endocytosis?
The process where particles are engulfed by the cell surface membrane flowing around them.
What is the difference between diffusion, osmosis, and active transport?
Diffusion and osmosis are passive processes; active transport requires energy (ATP).
What types of substances are moved by diffusion?
Gases or solutes (e.g., oxygen, CO2).
What type of membrane is required for osmosis?
A partially permeable membrane.
What is the direction of movement in active transport?
Low → high (against gradient).
What happens to an animal cell when solute concentration inside increases?
It can burst (cell lysis) due to too much water.
What are some substances that cannot cross a membrane by diffusion or active transport?
Some particles that are too large.
