Biology - Tripple Flashcards
If a cell is short of water what happens?
The solution inside will become more concentrated and the solution outside will become more dilute this would cause more water to move into the cell
What is osmosis?
Is the movement of water molecules across a partially permeable membrane from an area of high water concentration to an area of low water concentration
If a cell has too much water what happens?
The solution inside the cell becomes more dilute whereas the solution outside the cell becomes more concentrated this means water will leave the cell
If a cell is put in pure water what happens?
It will burst as water will be continually going into the cell
If the cell is pit in a salt solution?
The cell will shrink as all the water will leave the cell
Why do plants need osmosis?
To support their stem and leaves
How do plants use osmosis to support their stem and leaves?
Water moves into the plant cell by osmosis this causes the vacuole to swell and press the cytoplasm against the plant cell wall which causes the pressure to grow until no more water can enter the cell making it rigid and hard
What is active transport?
The movement of substances against a concentration gradient or across a cell membrane using energy from respiration
What do root hair cells in plants do?
On surface of plant roots
Gives the plant a big surface area for absorbing water and mineral ions from the soil
When is active transport used in humans?
It is used when there is a low concentration of nutrients in the gut but a high concentration in the blood
What do sports drinks do?
Water and ions replace those lost in sweat
Sugar replaces sugar lost in muscles
Name the main adaptations for exchange processes
Thin - short distance to diffuse
Large surface area - lots of substances can diffuse at once
Lots of blood vessels
Ventilation- move air in and out
How do plants gas exchange?
Air space - co2 diffuse out and 02 in easily so photosynthesis can happen quickly
Stomata - allows gases to move in and out
O2 and water vapour - diffuse out and water vapour can be lost through leaves
Guard cells - control opening and closing of stomata
Shape - flattened to increase surface area
Waxy cuticle - stops water loss
What do the alveoli do in the lungs?
- tiny air sacs give more surface area so there is more effective diffusion and they have a rich blood supply thus increasing the concentration gradient
- spherical shape gives more surface area
- very thin walls give a short distance making diffusion easier
What is the thorax?
It is the top part of the body
How does air enter the lungs? The system
Goes through the trachea
Then splits into two tubes called bronchi
Bronchi splits into smaller tubes called bronchioles
Bronchioles end in alveoli
How does breathing in work?
Intercostal muscles and the diaphragm contract
Thorax volume increases
Thus decreasing the pressure drawing air in
How does breathing out work?
Intercostal muscles and diaphragm relax
Thorax volume decreases
Thus increasing the pressure forcing air out
What is negative pressure?
A system where the external pressure is lower than the internal pressure
What is positive pressure?
A system where the external pressure is higher than the internal pressure
Is an iron lung negative or positive pressure?
Negative
How does an iron lung work?
Patient put inside long vacuum
Air pumped out the pressure is dropped this causes lung expansion and air is drawn in
Air pumped in and the pressure is increased this causes the lungs to decrease and air is drawn out
How does positive pressure work?
Air is pumped into the lungs this expands the ribcage and when they stop pumping air is pushed back out of the lungs
How does a plant transport food?
Phloem
Through phloem tubes which are made out of living cells with small holes in the end to allow things to flow through
Transport food made in the leaves to growing regions and storage organs
Goes in both directions
How does a plant transport water?
Xylem
Xylem tubes are dead cells joined end to end with no end walls between them and one whole down the middle
They carry minerals and water in a transpiration stream from the roots to the steam and leaves
Only goes up
What is transpiration?
The loss of water vapour from the leaves of the plant through the stomata when they are opened to allow gas exchange for photosynthesis
What is a transpiration stream?
The movement of water through a plant from the roots to the leaves as a result of of water loss by evaporation from the surface of the leaves
How do you control water loss?
Wilt so surface area is reduced
Waxy layer
Stomata closes