B3.1 Flashcards
What are the cells, tissues and organs in plants and animals adapted to do
To take up and get rid of dissolved substances
What can different conditions affect in cells
The rate of transfer
What might be needed sometimes for transfer to take place
Energy
How do dissolved substances move
By diffusion or active transport
How does water move across boundaries
By osmosis
What is osmosis
The diffusion of water from a dilute to a more concentrated solution through a partially permeable membrane that allows the passage of water molecules
What do differences in the concentrations of solutions inside and outside a cell cause
Water to move into or out of the cell by osmosis
What do most soft drinks contain
Water
Sugar
Ions
What does the sugars in sports drinks do
Replace the sugar used in energy release during the activity
Why do sport drinks contain water and ions
To replace the water and ions lost during sweating
What do sport drinks contain
Water
Ions
Sugars
What happens if water and ions are not replaced
The ion/ water balance is disturbed and the cells do not work efficiently
What are some substances absorbed against and what does it require
A concentration gradient and requires energy from respiration. This process is called active transport
What is active transport
Molecules are moved in and out of a cell using energy
When is active transport used
When transport needs to be faster than diffusion
What can be transported using active transport
Minerals, glucose and mineral ions
What does active transport enable cells to do
To absorb ions from very dilute solution
What type of movement is diffusion and why
Passive movement because it requires no energy
What are many organs specialised for
Exchanging material
How is the effectiveness of an exchange surface increased
By having a large surface area
Being thin so a short diffusion path
(In animals) having an efficient blood supply and being ventilated
What increases the difficulty of exchanging materials
The size
Complexity
What increases the surface in the small intestine
Villi
How does the villi increase the rate of exchange
The epithelial tissue of the villi have micro villi
1 cell thick wall so short diffusion distance
Long network of capillaries so fast absorption
What does the lacteal in the villi do
Absorbs fatty acids and glycerol
What increases the surface area of the lungs
Alveoli
How is the alveoli adapted for gas exchange
1 cell thick- short diffusion distance
Lining is moist-easier for gases to exchange
Excellent blood supply-faster absorption of O2 or CO2
Where is the lungs in the body
Upper part of the body, protected by the ribcage and separated from the lower part if the body by the diaphragm
What happens when u inhale
Intercostal muscles contract Ribcage lifts up and out Diaphragm contracts Lung volume increases Pressure decreases Air flows into lungs
What happens when u exhale
Intercostal muscles relaxes Ribcage goes down and in Lung volume decreases Pressure increases Air goes out of lung
Why does the breathing system takes air in and out of the body
So that oxygen from the air can diffuse into the bloodstream and carbon dioxide can diffuse out of the bloodstream
What is ventilation
The movement of air into and out of the lungs
What are absorbed by the roots
Water and mineral ions
How does carbon dioxide leave the plant
By diffusion
How is the surface area of roots increased
By root hairs
What is the surface area if leaves increased by
The flattened shape
Internal air space
Thin walls
What does the stomata do
To obtain carbon dioxide from the atmosphere and to remove oxygen produced in respiration
What process where plants lose water vapour from their leaves
Transpiration
Where in cells are water lost
Stomata
When is evaporation in plants more rapid
Hot, dry and windy conditions
What happens if a plants lose water fast
Replaced by the roots
Stomata can close to stop wilting
What is the size of stomata controlled by
Guard cells which surrounds them
What is the rate of transpiration
How fast evaporation in the leaves takes place
How does light intensity affect the rate of transpiration
It increases so more stomata opens to a point where all the stomata are open
Why does light intensity only increase the rate of transpiration only to a certain point
No more stomata can open
How does temperature affect the rate of transpiration
The higher the temperature, the faster the water molecules are moving the air so therefore evaporate from leaf quicker
How does wind speed affect the rate of transpiration
The faster the water molecules move in the air,
The faster water will be removed
Diffusion of water out of leaf increases
Rate of transpiration increases due to a high concentration gradient
How does humidity affect the rate of transpiration
The less humid, the less water in the air
Water will diffuse more quickly
Increase in rate of transpiration
Higher concentration gradient between inside and outside of leaf
