Transport in Cells Flashcards
What is diffusion?
Diffusion is the net movement of particles from one area of high concentration to an area of low concentration down a concentration gradient. It is a passive process so no energy is needed and occurs until equilibrium.
What can pass through the cell membrane by diffusion and what can’t?
CAN:oxygen, glucose, amino acids, water
CANT:starch, proteins
What is a dilute solution?
When a solution has a HIGH water concentration
What is a concentrated solution?
When a solution has a LOW water concentration
What is osmosis?
The movement of water particles from a dilute region to a concentrated region down a concentration gradient across a partially permeable membrane
What is a hypotonic solution?
When there is more water OUTSIDE the cell, water will move IN via osmosis.
What is a hypertonic solution?
Less water OUTSIDE than inside cell so water LEAVES cell via osmosis
What is an isotonic solution?
When there are equal amounts of water inside and outside solution so there is no NET MOVEMENT.
What happens to an ANIMAL cell in a HYPERTONIC solution?
Water leaves cell so the red blood cell shrivels and becomes CRENATED.
What happens to an ANIMAL cell in a HYPOTONIC solution?
Water moves IN but the red blood cell bursts as there is TOO MUCH water. This is called LYSIS.
What happens to a PLANT cell in a HYPERTONIC solution?
Water leaves VACUOLE via osmosis but some water remains. Shape of cell is less rigid but as more water leaves vacuole becomes SMALLER and CYTOPLASM and CELL MEMBRANE fade away. The cell has PLASMOLYSED or become FLACCID
What happens to a plant cell in a hypotonic solution?
Water moves IN so cell gains lots of water and expands. Cell will not BURST as it has a RIGID CELLULOSE WALL and animal cell doesn’t. The cell is TURGID.
What can affect the rate of DIFFUSION?
Difference in concentrations
The temperature
The surface area
What can increase the effectiveness of an exchange surface?
Having a large surface area
A membrane that is thin
having an efficient blood supply
being ventilated
What is active transport?
Active transport moves substances from a more dilute solution to a more concentrated solution( AGAINST a concentration gradient). This requires energy in the form of ATP from respiration.
What does active transport help with?
Allows mineral ions to be absorbed into plant root hairs from very dilute solutions in the soul. It also allows sugar molecules to be absorbed from lower concentrations in the gut into the blood which has a higher sugar concentration. Sugar is used for CELL RESPIRATION.
How are lungs an effective EXCHANGE SURFACE?
Lungs have alveoli which have a LARGE SA and have very thin walls, capillaries surround alveoli ensuring GOOD BLOOD SUPPLY and lungs are WELL VENTILATED.
Why is the small intestine an effective EXCHANGE SURFACE?
Projections called VILLI and MICROVILLI increase surface area for absorption.Blood capillaries inside maintain good blood flow and transport molecules away to maintain a concentration gradient.Villi also have a THIN PERMEABLE MEMBRANE for a shorter diffusion path.
Why are gills an effective exchange surface?
Feather projections called filaments to increase SA for gas exchange. Water pumped over gills for a steep concentration gradient and for ventilation. Thin walls to provide short diffusion path and capillaries ensuring good blood supply.
How are leaves an effective exchange surface?
FLATTENED SHAPE to increase surface area for gas exchange.Small holes that allow for movement of gases to keep ventilated. Very thin to ensure short diffusion path.
