Week 11 Nutrient transport Flashcards
What is the primary function of the cell membrane?
Prevents entry of some substances
Retain other substances
What are the other roles of the cell membrane?
Regulates rate of transport of fuel into the cell
Provides surface for attachment of proteins
Communication between extra and intra-cellular environments
What is the cell membrane made of?
Phospholipids
What is the permeability of the cell membrane?
Semi-permeable
What does semi-permeable mean?
Allows small uncharged molecules to pass with no problem
Large molecules require transport mechanisms
What are the two types of transport?
Passive and active
What is passive transport?
Requires no energy other than molecules motion
What is active transport
Require ATP
What the the four types of passive transport?
Simple diffusion
Facilitated diffusion
Osmosis
Filtration
What are the types of active transport?
Sodium-potassium pumps
Bulk transport
What are the types of bulk transport?
Endocytosis
Exocytosis
Phagocytosis
What is simple diffusion?
The passive movement of molecules or particles from regions of higher to lower concentration
What is facilitated diffusion?
Transport of substances across a biological membrane from an area of higher concentration by means of a carrier molecule
What does facilitated diffusion require?
A trans-membrane protein. (a carrier)
What is osmosis?
Simple diffusion of water, rather than molecules or particles, water travels towards higher concentration of solute. The water move to maintain an equal ratio.
What happens to the net movement of water when the water is isotonic and why?
There is no net movement because the solution concentration is the same
What happens to the net movement of water when the water is hypotonic and why?
Net movement of water into the cell because the cell has a higher concentration than the water
What happens to the net movement of water when the water is hypertonic and why?
There is a net movement of water out of the cell because the cell has a lower concentration.
What is filtration?
Movement of water and solutes across the membrane due to hydrostatic pressure from the CV system. (kind of like a sieve)
What does the sodium potassium pump do?
It actively transports sodium out of cells whilst simultaneously pumping potassium in to cells.
Why is the sodium-potassium pump an active process?
Costs ATP as it is against the concentration gradient.
Why do we need sodium to be removed from the muscle?
So when we need to contract the muscle sodium can rapidly move into the muscle cell, setting of a chain of events resulting in the muscle contracting
What happens to the cells in endocytosis?
Bulk transport into the cells
What happens to the cells in exocytosis?
Bulk transport out of the cell
What is phagocytosis?
The ingestion of bacteria or other material by phagocytes
