B2 Cell Transport Flashcards
(34 cards)
What is the meaning of ‘diffusion’?
The spreading out of particles, resulting in a net movement from an area of higher concentration to an area of lower concentration.
What is the definition of the word ‘osmosis’?
The diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane.
What is the definition of the phrase ‘active transport’?
The movement of particles from a more dilute solution to a more concentrated solution using energy from respiration.
What is the movement of particles like in diffusion?
Particles move down the concentration gradient - from an area of high concentration to an area of low concentration.
What is the movement of particles like in osmosis?
Water moves from an area of lower solute concentration to an area of higher solute concentration.
What is the movement of particles like in active transport?
Particles move against the concentration gradient - from an area of low concentration to an area of high concentration.
Is energy required for diffusion?
No, its a passive process
Does osmosis require energy?
Nope, it’s a passive process.
Does active transport require energy?
Yes- it uses the energy released by respiration.
How is diffusion used in human small intestines?
The nutrients in the small intestine diffuse into the capillaries through the villi.
How is diffusion used in human lungs?
Oxygen diffuses from the air in the alveoli into the blood in the capillaries. Carbon dioxide diffuses from the blood in the capillaries into the air in the alveoli.
How is diffusion used in human kidneys?
Urea diffuses from cells into the blood for excretion in the kidney.
How is diffusion used in fish?
•oxygen from water passing over the gills diffuses into the blood in the gill filaments.
•carbon dioxide diffuses from the blood in the gill filaments into the water.
How is diffusion used in plants?
•carbon dioxide used for photosynthesis diffuses into leaves through the stomata.
•oxygen produced during photosynthesis diffuses out of the leaves through the stomata.
How is osmosis used in plants?
Water moves by osmosis from a dilute solution in the soil to a concentrated solution in the root hair cell.
How is active transport used in humans?
It allows sugar molecules to be absorbed from the small intestine when sugar concentration is higher in the blood than in the small intestine.
How is active transport used in plants?
It’s used to absorb mineral ions into the root hair cells from more dilute solutions in the soil.
What factors affect the rate of diffusion?
• difference in concentration
•temperature
•surface area of the membrane
How does difference in concentration affect the rate of diffusion?
The steeper the concentration gradient, the faster the rate of diffusion.
How does temperature affect the rate of diffusion?
The higher the temperature, the faster the rate of diffusion.
How does surface area of the membrane affect the rate of diffusion?
The larger the membrane surface area, the faster the rate of diffusion.
Do single celled organisms have a small surface area-to-volume ratio?
No! They have a large surface area-to-volume ratio.
Why do single celled organisms have large surface area-to-volume ratios?
So enough molecules can be transported across their cell membranes to meet their needs.
Do multicellular organisms have small surface area-to-volume ratios?
Yes, they do!
