2h - Transport Flashcards
How do unicellular organisms get their supply of oxygen and nutrients?
By diffusion through the membrane of their cell.
Because they are so small and have a large SA/vol ratio
How do bigger organisms get their supply of oxygen and nutrients to their cells?
They have to develop a system to deliver oxygen and nutrients to all cells quickly.
(small SA/vol ratio)
What does the phloem transport?
Sucrose and amino acids
What does the xylem transport?
Water and dissolved minerals
What is the phloem made of?
Sieve plates which have holes in the end of cell walls to allow an easy flow of substances
What is the xylem made of?
No cell wall at the end of the cells so forms continuous tubes
In which directions does phloem deliver sucrose and amino acids?
Two direction,
Up + down
In which direction does xylem deliver water and dissolved minerals?
One way only
Up ^
What does the xylem offer alongside transportation?
Supports the plant
What is the percentage of plasma in the blood?
55%
What is the percentage of all blood cells in the blood?
45%
Aside from transportation, what is another function of plasma?
Maintaining body temperature
What does plasma transport?
- Digested food to cells (for respiration or assimilation)
- Urea to the kidney (excreted as urine)
- Hormones (stimulate changes in body conditions)
- Waste CO2 (from respiring cells to the lungs for exhalation)
How can the shape of a red blood cell be described?
Biconcave
What is an advantage of the ‘biconcave’ shape of a red blood cell?
Large SA/ vol ratio for the most efficient rate of diffusion of oxygen
Why are red blood cells small and flexible?
So they can squeeze through narrow blood vessels and capillaries
What is the main function of a red blood cell?
Carry oxygen around the body
What are the two types of white blood cells?
- Lymphocytes
- Phagocytes
How do lymphocytes destroy bacteria?
Produces antibodies which attach to the antigens of a bacteria. This causes the bacteria to burst or stick together for phagocytes to detect them easily.