transport Flashcards
2 reasons why unicellular organisms can rely on diffusion alone
- they have a large surface area to volume ratio due to their size
- they have low metabolic demands
what products and direction does the phloem transport
transports sugars like sucrose up and down the plant from source to sink
what products and direction does the xylem transport
transports water and minerals up the plant from the root to the leaves
how are root hair cells adapted to their function
they have a long root hair extension to increase surface area for uptake, and thin membranes to decrease the diffusion distance
three benefits of transpiration
- the stream of water cools the plant
- the water helps to support the plant by creating turgor pressure
- the plant has a constant water supply for photosynthesis
how is the xylem adapted to transport water
it is waterproofed using a substance called lignin
the xylem cells are dead and have no organelles so there is more space for water
what is translocation
the movement of sugars up or down the phloem from source to sink
what is the function of platelets
small fragments of cells that are involved in blood clotting
2 benefits of blood clotting
- it prevents the entry of microorganisms
- it prevents blood loss
two ways the body can respond to detecting a pathogen
- lymphocytes can produce antibodies that are specific to the antigens on the pathogen
- phagocytes can engulf the pathogen
which direction do veins and arteries carry blood
veins carry blood towards (INto) the heart, arteries carry blood away from the heart
structure of arteries
they have thick walls made of muscle and elastic tissue and a small lumen to transport blood under high pressure
structure of capillaries
they have thin walls about one cell thick to allow for the easy exchange of substances at the tissues
structure of veins
have less muscle and elastic tissue than arteries and they have a larger lumen as the blood is at a lower pressure, they also have valves to prevent back flow
blood flow through the right side of the heart
- deoxygenated blood flows into the right atrium from the vena cava
- this blood passes through the right AV valve in the right ventricle
- the blood is then pumped out of the heart to the lungs through the right SL valve and into the pulmonary artery
blood flow through the left side of the heart
- blood enters into the left atrium from the pulmonary vein
- the blood is then pumped through the left AV valve into the left ventricle
-the blood is then pumped out through the left SL valve and into the aorta
what is the septum
the wall that separates the right and left side of the heart
what does the coronary artery supply the heart tissue with
blood
what does adrenaline do
dilates the pupils and increases the breathing rate
capillaries flow…
close to tissues for exchange
