Exchange and Transport Flashcards
How do you find surface area to volume ratio?
surface area to volume, simplified
How is urea removed from the body?
-via skin through sweat
-via kidneys in urine after having diffused from cells in the blood plasma for removal
How does exchange occur in single celled organisms?
Gases and dissolved substances can diffuse directly into or out of cell across the cell membrane. They have a large SA:V ratio, so enough substance can be exchanged over the membrane to supply the volume of the cell.
Where does gas exchange occur in mammals?
alveoli of lungs
How are alveoli adapted for gas exchange?
- large surface area
- good blood supply
- thin walls (one cell thick) - short diffusion pathway
- moist - dissolve gases
How do you calculate rate of diffusion?
surface area x difference in concentration / length of diffusion path
What are the three factors which affect rate of diffusion?
Distance, concentration gradient/ difference, Surface Area
What is the equation for aerobic respiration?
glucose + oxygen -> carbon dioxide + water
What is the formula equation for aerobic respiration?
C6H12O6 + 6O2 -> 6CO2 + 6H2O
When is anaerobic respiration used?
Anaerobic respiration happens when there’s not enough oxygen available.
What are the disadvantages of anaerobic respiration?
- produces lactic acid that causes cramps
- produces less energy
What is the equation for anaerobic respiration in plants?
Glucose -> ethanol + carbon dioxide
What is the formula for anaerobic respiration in animals?
glucose -> lactic acid
How can you measure rate of respiration?
In aerobic respiration, organisms use up oxygen. By measuring the amount of oxygen consumed by organisms in a given time, you can calculate the rate of respiration. You can do this using a respirometer
How can you investigate effect of temperature on rate of respiration?
- soda lime added to both test tubes (absorbs CO2)
- a ball of cotton wool is placed on top, and in one tube woodlice are added, glass beads are added to the other one
- set up respirometer
- syringe adds a known level of liquid to the manometer
- left for a set period in a water bath at 15 degrees
- air volume in woodlice tube will decrease, O2 used, CO2 absorbed
- reduces pressure in tube, drawns liquid in manometer towards the tube.
-distance moved in a given time is measured, and you can calculate volume of O2 absorbed per minute, this is the rate of respiration
-repeat with different temperatures