movement in and out of cells Flashcards
What is diffusion and why is it important in transport in cells?
Diffusion is a type of passive transport in cells, where substances move from an area of high concentration to an area of low concentration using a semi permeable membrane formed by a bi-layer. It is important in transport in cells because it allows for the movement of substances such as oxygen, nutrients, and waste products in and out of cells.
How does diffusion work in transport in cells?
Diffusion is a passive transport in cells that needs no energy, but instead uses kinetic energy, which is when molecules are constantly moving in random directions. When there is a difference in concentration between two areas, molecules will move from the area of high concentration to the area of low concentration until the concentration is equal.
What is the difference between diffusion and osmosis in transport in cells?
Diffusion and osmosis are both types of passive transport in cells. The main difference between the two is the type of substance being transported. In diffusion, substances move from an area of high concentration to an area of low concentration without the help of a membrane protein. In osmosis, water molecules move from an area of high concentration to an area of low concentration across a selectively permeable membrane.
What is facilitated diffusion and how does it differ from simple diffusion in transport in cells?
Facilitated diffusion is a type of passive transport that uses membrane proteins, such as protein channels, instead of phospholipids in the bi-layer. It is used by molecules that are unable to pass the bi-layer (eg glucose and amino acids.)
Explain how diffusion works in relation to the lungs.
The oxygen that is made by gaseous exchange diffuse from the higher concentration in the alveoli through the alveolar walls, to a lower concentration in the blood in the capillaries that line the alveolar walls.
Define osmosis
osmosis is the diffusion of water molecules through are semi permeable membrane, which dilate from a HIGH concentration to a LOW concentration until both sides reach equilibrium. (Down a concentration gradient). This is a type of passive transport, so doesn’t need energy.
Define active transport
Active Transport is when dissolved molecules move across a cell membrane from a low to high concentration. The particles move against the concentration gradient, so will need energy (ATP) to be able to do this. If aerobic respiration stops, then active transport will also stop as there is no energy.
What is facilitated diffusion?
When certain substances, such as large molecules like glucose, cannot diffuse through the phospholipid bilayer of the cell membrane, so need the aid of certain proteins (Channel and Carrier) to be able to diffuse from high to low concentration.
