3- Exchange of materials Flashcards
What is osmosis
The diffusion of water from a dilute concentration to a concentrated solution through a partially permeable membrane
What happens when red blood cells are in more dilute solution
Water goes into the red blood cell and the cell bursts due to the pressure
What happens when red blood cells are in more concentrated solution
The red blood cells water travels out of the it and it collapses
What happens when a plant cell is in more concentrated solution
The plant cells water travels out of it and it shrinks but does not collapse because of the cell wall
What happens when a plant cell is in more dilute solution
Water goes into the plant cell and it swells up but does not burst because of the cell wall
What is concentration
The measure of the number of particles of a solute in the solution
What is distilled water
Pure water
What is miscible liquids
Liquids that dissolve in each other
What is the net movement
Overall movement
What is a partially permeable membrane
A membrane which let’s some substances pass through, but not others
What are pores
The holes in the partially permeable membrane
What is a solution
A solid or gas dissolved in a liquid. Or two miscible liquids dissolved
What is a solute
A dissolved substance in a solution
What is a solvent
The liquid used for dissolving
What is active transport?
The movement of particles against the concentration gradient (from low to high) through a partially permeable membrane. Energy released from respiration is required
Examples of active transport?
Glucose in an animal cell (small intestine and kidney also)
Mineral ions into route hair cells
Why is active transport necessary?
Cells may need to absorb substances which are in short supply (shorter supply than the cell has in it’s supply)
What happens in your body while you exercise?
Glucose is used when your muscles respire to release energy. When the body becomes hot, you sweat more to cool down meaning you lose water and mineral ions
What are the three basic ingredients in sports drinks?
Water, sugar and mineral ions
What are sports drinks designed to do?
Balance the concentration of body fluids and concentration inside cells
If the drink concentration matches the body fluids, the solution is called isotonic
What do scientists think of sports drinks?
Some think water is more effective, others think it is better because of the sugars and mineral ions. The general consensus is that is is only effective when exercising for a long period of time
What is an exchange surface and give an example?
A surface on which materials are exchanged
Oxygen is absorbed by the lungs and carbon dioxide is removed from them (the gaseous exchange surface)
What are qualities of an efficient exchange surface?
Large surface area, thin walls (short diffusion path), an efficient transport system
What qualities does the lungs have that makes it so efficient?
Surface area increased by the alveoli (air sacks)
Ventilated to maintain a steep diffusion gradient
Describe the process of gaseous exchange of the breathing system? (Detail)
Oxygen diffuses into the many capillaries surrounding the alveoli and carbon dioxide diffuses back out into the lungs to be breathes out
Where are the lungs situated?
In the thorax, inside the rib age and above the diaphragm which separates the lungs from the abdomen
What happens when we breath in?
The intercostal muscles (between ribs and diaphragm) contract
The ribcage moves up and out
The diaphragm flattens
The thorax’s volume increases and pressure decreases
What happens when we breath out?
The intercostal muscles (between the ribs and diaphragm) relax
The ribcage moves down
The diaphragm becomes domed
The thorax’s volume decreases and pressure increases
What is the diaphragm?
A strong sheet of muscle that separates the thorax and digestive organs, used to change the volume of the chest during ventilation of the lungs
What is ventilation? (In terms of lungs)
The movement of air in and out of the lungs
Give three reasons why someone cannot get enough oxygen into their blood stream?
If the alveoli is damaged (surface area decreased)
Tubes leading to lungs narrowed
Person is paralysed, muscles for ribcage will not work
What are the three types of breathing aid? (Brief description)
~Iron lung - for people with polio or paralysed, a machine (metal cylinder) acts as your lungs and muscles
~Breathing aids - force measured amounts of air into the lungs to create a positive pressure (bag of air mask)
~Positive pressure aids - a smaller, more practical version of breathing aids
What is the exchange surface for food molecules? Describe
The villi, lining of the inner surface of the small intestine.
They are finger like projections which greatly incense the surface area, the walls are very thin with many capillaries close to them
Describe the exchange of food molecules in the gut?
Food is digested in the gut into soluble molecules which are then absorbed into the blood in the small intestine. Diffusion or active transport takes place on the exchange surface that is the villi
What is a stomata and what does it mainly do?
Oxygen and carbon dioxide diffuse (not very far because of the thinness) in and out of leaves through tiny holes called stomata. They size of them are controlled by guard cells (which surround them).
The movement of the gasses depend on what process (photosynthesis or respiration) is taking place most quickly
Why is oxygen needed in plants?
For respiration and is a waste product of photosynthesis
Why is carbon dioxide needed in plants?
For photosynthesis and is a waste product of respiration
What else does the stomata do, besides gas exchange?
Plants lose water vapour from leaf cells through the stomata due to evaporation in leaves
What happens if plants lose water faster than the roots replace it?
The stomata can close to prevent willing
What is the transpiration system?
The movement of water through the plant
What inhances water evaporation in leaves?
Hot, dry, bright or windy conditions
What can the guard cell do to prevent water loss in plants?
Can close or the leaves can wilt or collapse down to prevent water loss,
What can a potometer measure?
The uptake of water by a plant with different conditions
