Transport review B2.1 Flashcards
Passive transport?
When a substance moves from an area of high concentration to an area of lower concentration
- Transport that does not require cellular energy (ATP)
Types of passive transport?
- Osmosis
- Facilitated diffusion
Active transport?
Involves movement of substances against a concentration gradient
- Needs energy (ATP)
Types of active transport?
Sodium potassium pump
How does osmosis work?
Passive movement of water across a partially permeable membrane ( one that allows certain substances through)
- Water moves through hypotonic solution to hypertonic
Hypotonic vs hypertonic?
Hypotonic: Lower concentration of solutes
Hypertonic: Has higher concentration of solutes
How does facilitated diffusion work?
Involves two types of integral proteins: Carrier and Channel
What do carrier proteins do in facilitated diffusion?
Change shape in order to carry a specific substance from one side of the membrane to other and along a concentration gradient
- No transport if carrier not working
What do channel proteins do in facilitated diffusion?
They have gates that open and close in response to mechanical or chemical signals
- Only carry water-soluble molecules
- Are specific to the ion they carry
How does the sodium potassium pump work?
Uses ATP to move ions directly against a concentration gradient
What is indirect active transport?
Transport that uses energy produced by the movement of one molecule down a concentration gradient to transport another molecule against a gradient
Steps involved in indirect active transport?
- There are more sodium ions outside than inside of intestinal cell
- Sodium ions and glucose molecules bind to specific transport protein on extracellular surface
- Sodium ions pass through the carrier to the inside of the cell down a concentrating gradient, with the carrier capturing the energy released by this movement
- The captured energy is used to transport the glucose molecule through the same protein into the cell
