B3.1 - Movement Of Molecules In And Out Of Cells Flashcards
What molecules does osmosis apply to?
Water molecules.
What do water molecules move across during diffusion?
A partially permeable membrane.
What causes osmosis to occur?
A difference in water concentration inside and outside the cell.
What do most soft drinks contain? (3)
- Water.
- Sugar.
- Ions.
Why do sports drinks contain sugars?
To replace the sugars broken down in energy release during exercise.
Why do sports drinks contain water and ions?
To replace the water and ions lost during sweating.
What happens if water and ions are not replaced after exercise?
The balance of the body is disturbed and cells are unable to work as efficiently.
What are the ways in which dissolved substances can move in and out of cells? (2)
- Diffusion.
2. Active transport.
What are the differences between active transport and diffusion? (2)
- Active transport goes against the concentration gradient.
2. Active transport requires energy.
Where does the energy for active transport come from?
Respiration.
What does active transport allow cells to do?
To absorb ions from very dilute solutions.
How are exchange surfaces made more effective? (4)
- A large surface area.
- Being thin (to provide a short diffusion path).
- An efficient blood supply.
- Being ventilated (for gas exchange).
What increases the surface area of the lungs?
The alveoli.
What increases the surface area of the small intestine?
Villi.
What is absorbed by the villi?
The products of digestion.
What does the ribcage protect?
The lungs.
What is the upper part of the body called?
The thorax.
What is the lower part of the body called?
The abdomen.
What separates the upper and lower parts of the body?
The diaphragm.
What does the breathing system do with gases in the air? (2)
- Allows oxygen from the air to diffuse into the bloodstream.
- Allows carbon dioxide to diffuse out of the bloodstream and into the air.
What does the thorax do in order to move air into the lungs?
The ribcage moves up and expands, and the diaphragm flattens.
What does the thorax do in order to move air out of the lungs?
The rib cage moves downwards and contracts, and the diaphragm is pulled down.
How does carbon dioxide enter the leaves?
Diffusion.
Where are most of the water and mineral ions absorbed in plants?
The roots.
How is the surface area of the roots increased?
Root hairs.
How is the surface area of leaves increased? (2)
- Flattened shape.
2. Internal air spaces.
What do the stomata do in gaseous exchange? (2)
- Obtain carbon dioxide from the atmosphere.
2. Remove oxygen produced in photosynthesis.
Where do plants mainly lose water from?
The leaves.
In what conditions is evaporation from the leaves most rapid?
Hot, dry and windy conditions.
What do the stomata do when the plant is losing more water than it can replace?
Close.
Which cells control the size of the stomata?
Guard cells.
How do modern ventilators work?
Pumping air into the lungs through a tube.
How did an “iron lung” work?
The patient was in a giant case with only their head out, and air was pumped in and out of the case to increase and decrease the pressure.
Which method of ventilation interferes with blood flow?
An iron lung.
What can be a disadvantage of modern ventilation?
Alveoli can burst.
