Chapter 1: Exchange of materials Flashcards
What is the difference between diffusion and osmosis?
Diffusion relates to the movement of any substance. Osmosis is specifically the movement of water.
What does water do in Osmosis?
Moves to dilute a more concentrated solution of a substance
A less concentrated solution is inside a bag with a permeable membrane. Which way will water move?
Out of the bag to dilute the more concentrated solution outside of it.
Between which two mediums does osmosis occur in cells?
The cytoplasm and the cell membrane.
If a red blood cell was placed in a salt solution, where would water diffuse?
Out of the cell to try and dilute the salt solution. The cell would shrivel up.
If a red blood cell was placed in distilled water, where would water diffuse?
Into the red blood cell to try and dilute the substance filled contents of the cell. The cell would swell and burst.
Where does water diffuse into in plants?
The Permanent Vacuole
Why do plants that do not receive enough water wilt?
A protection mechanism that prevents further water loss by reducing surface area.
When does a cell need to use active transport?
When it needs to move substances against a concentration gradient.
How does active transport work?
A ‘Transport’ Protein has has a hollow in which useful molecules fall into. It then rotates inside the organism and drops the molecule off, before rotating back around.
Why is active transport needed in plant roots?
The concentration of Ions in the soil is very low.
Why are the rates of active transport and the rates of respiration closely linked?
Because active transport requires a lot of energy to move molecules.
Why do cells become de-hydrated during exercise?
Water is lost through sweat, meaning that the concentration of water in the bloodstream lowers. This means that water will diffuse out of cells.
How do sports drinks combat de-hydration?
They contain lots of water and mineral ions to restore the amount of water/mineral ions in the blood stream.
Where does gas exchange take place inside the lungs?
Inside air sacs called alveoli
What happens inside alveoli?
Oxygen is exchanged for carbon dioxide through diffusion
What 3 factors create rapid gas exchange inside the lungs?
Ventilation (Breathing rate), large surface area and blood flow.
What is the diaphragm?
A sheet of muscle below the lungs that contracts to increase pressure in them and relaxes to decrease pressure.
What are the muscles between a persons ribs called?
Intercostal muscles
How is a high concentration gradient maintained in the gut?
Good blood flow
What is special about the lining of the gut which helps with diffusion?
It is folded into many finger like folds called villi. These increase surface area.
How is a Villus adapted to aid diffusion?
Outer cells have micro villi, only one cell thick wall, large surface area, rich blood supply.
What is transpiration?
The evaporation of water from a plant leading to more water being taken up through the roots.
What factors affect the rate of transpiration?
Humidity, Temperature and Windspeed
Where is the Transpiration stream?
Inside the Xylem
How does a plant control the rate of Transpiration?
Opens/closes stomata
