Some BY2 questions Flashcards
Explain the process of the chloride shift.
CO2 diffuses into the RBC combining with H2O to form carbonic acid. This reaction is catalysed by carbonic anhydrase.
Carbonic acid dissociates into H+ and HCO3- ions. HCO3- ions diffuse out RBC into plasma combining with NA+ ions from dissociation of sodium chloride to form sodium hydrogen carbonate.
H+ ions provide the conditions for the oxyhaemoglobin to dissociate into O2 and haemoglobin.
H+ ions are buffered by their combination with haemoglobin and the formation of haemoglobinic acid(HHb).
The O2 diffuses out RBC into tissues.
To balance outward movement of -ve charged ions chloride ions diffuse in.
Its by this that the electrochemical neutrality of the RBC is maintained.
Give 3 characteristics of a closed loop blood system.
Blood is pumped by a muscular heart at high pressure resulting in a rapid flow rate.
Organs not in direct contact with blood but are bathed by tissue fluid leaking out of capillaries.
Blood circulates in continuous system of tubes, blood vessels.
Blood contains a blood pigment which carries O2.
Explain how an open loop blood system operates in an insect.
Blood is pumped at relatively low pressure from one main long, dorsal tube shaped heart running the length of the body. The blood is pumped out of this heart into spaces called haemocoel within the body cavity.
Blood bathes tissues directly, exchange of materials takes place, little control over the direction of circulation.
Blood slowly returns to the heart.
Valves and waves of contraction of the muscle wall move blood forward to the head region where the open circulatory is started again.
No respiratory pigment as blood doesn’t transport oxygen.
Oxygen is transported directly to the tissues via the tracheae.
Define the term cohesion.
Water molecules tend to stick together.
Define the term adhesion.
The water molecules stick to the wall of the xylem.
Define the term capillarity.
The tendency for water to rise in narrow tubes.
What is the main force pulling water up the stem?
Transpiration pull.
What is the theory of the mega ism by which water moves up the xylem?
The cohesion tension theory.
What does taxonomic hierarchy mean?
A classification system used to categorise organisms.
What are the 3 ways in which CO2 is transported in blood cells and plasma.
In solution in the plasma(5%).
As hydrogen carbonate(85%).
In combination with haemoglobin to form carbamine-haemoglobin(10%).
