Cell Transport - Passive & Active Transport Flashcards
What are the TWO types of cell transport?
Passive transport & Active transport
PASSIVE TRANSPORT
Does NOT require ATP (energy). Moves ALONG the concentration gradient.
What are the THREE types of passive transport
Diffusion
Facilitated Diffusion
Osmosis
Diffusion (passive transport)
In diffusion particles will randomly spread out from a high concentration to a low concentration. This sets up a concentration gradient. Small uncharged molecules like O2, CO2, glucose, etc can freely pass through the membrane and go down the concentration gradient.
Factors that affect diffusion (passive transport)
- State (gasses diffuse faster than liquids)
- Size (small particles = faster diffusion)
- Temperature (higher temp = faster diffusion)
- Difference of high concentration and low concentration
Facilitated Diffusion (passive transport)
- Many ions and molecules cannot diffuse directly through the membrane because they are either too big or carry a charge.
- They need a protein channel or pore through the membrane to enter the cell.
- Transport proteins are specific: they only allow certain molecules to pass
Transport large molecules, or ions and molecules with a charge (e.g Na+, K+)
Particles still diffuse at random, but must pass through the channel.
Osmosis (passive transport)
Osmosis is the process of when water is diffused from a high concentration of water to a low concentration of water through a semi-permeable membrane
Osmoregulation
Cells are surrounded by water so they need to control the movement of water across the membrane
Hypotonic (low solute concentration, high water)
The concentration of solutes inside the cell is lower than outside of the cell. When a cell is put in a solution with a higher solute concentration and low water potential than the inside of the cell, water will move out of the cell from an area of high water to an area of low water. The cell loses water.
Hypertonic (high solute concentration, low water)
The concentration of solutes inside the cell is lower than outside of the cell. When a cell is put in a solution with a higher solute concentration and low water potential than the inside of the cell, water will move out of the cell from an area of high water to an area of low water. The cell loses water.
What are the THREE types of Active transport?
- Protein pump
- Endocytosis
- Exocytosis
Active Transport
The movement of particles against a concentration gradient, from an area of low concentration to an area of higher concentration. This process requires ATP energy and moves AGAINST the concentration gradient.
- chemical energy in a cell is stored as ATP (Adenosine Triphosphate)
- When ATP to converted to ADP, the reaction released energy. This energy is used to power protein pumps and move molecules across the membrane.
- Active transport is SELECTIVE and moves specific molecules from an area of low concentration to an area of high concentration.
Active Transport Process
- Active transport is performed by ion pumps and carrier proteins in the cell membrane.
- Specific substances bind to the carrier protein.
- ATP also binds and the carrier protein converts ATP to ADP, releasing energy.
- Energy causes the carrier protein to change shape, ejecting the substance the other side of the membrane.
- E.g absorption of glucose, moving charged ions.
Active Transport - Sodium Potassium ion Pump
Important for the functioning of nerve cells.
- Moves three NA+ out of the cell, and two K+ into the cell, using ATP for energy.
Active Transport - What are the two types of Cytosis
Endocytosis & Exocytosis
Active Transport - Endocytosis
The process by which substances are taken IN by the cell
What are the two types of endocytosis?
- Phagocytosis
- Pinocytosis
Endocytosis - What is PHAGOCYTOSIS
Solid particles
Endocytosis - What is PINOCYTOSIS
Fluids/Liquids
Exocytosis
The process by which substances are REMOVED from the cell.
e.g removing waste products
e.g excreting hormones
Substances are stored or packaged into membrane-bound vesicles within the cell. The vesicles are transported to the inner surface of the plasma membrane.
The vesicle membrane merges with the cell membrane, opening the vesicle tot he extra-cellular environment, and releasing the substances.
Active Transport - What is the process of active pumps in the membrane?
The process of active transport involves specific protein pumps. The protein pumps are made up of specific proteins called trans-membrane proteins. These pumps first make a complex with the substance to be transported across the membrane, using the energy derived from ATP.
