3.3.4: Mass transport in animals Flashcards
Describe why Binding of one molecule of oxygen to haemoglobin makes it easier for a second oxygen molecule to bind.
- Binding of first oxygen changes tertiary /
quaternary (structure) of haemoglobin;
Ignore ref. to ‘positive cooperativity’ unqualified
Ignore ref. to named bonds
Accept conformational shift caused - Creates / leads to / uncovers second / another
binding site OR
Uncovers another iron / Fe / haem group to bind to;
Explain how
changes in the
shape of
haemoglobin result
in the S-shaped
(sigmoid)
oxyhaemoglobin
dissociation curve
(2)
- First oxygen binds (to Hb) causing change in shape;
- (Shape change of Hb) allows more O2 to bind (easily)
/ greater saturation with O2
OR
Cooperative binding;
Haemoglobin is a
protein with a
quaternary structure.
Explain the meaning
of quaternary
structure (1).
(Molecule contains) more than one polypeptide (chain)
Describe the
advantage of the
Bohr effect during
intense exercise. (2)
- Increases dissociation of oxygen;
Accept unloading/ release/reduced affinity for
dissociation - For aerobic respiration at the tissues/muscles/cells
OR
Anaerobic respiration delayed at the
tissues/muscles/cells
OR
Less lactate at the tissues/muscles/cells;
Describe and
explain the effect of
increasing carbon
dioxide
concentration on the
dissociation of
oxyhaemoglobin. (2)
- Increases/more oxygen dissociation/unloading
OR
Deceases haemoglobin’s affinity for O2;
Accept more readily
Accept releases more O2 - (By) decreasing (blood) pH/increasing acidity;
Explain why haemoglobin curve shifts left when diving (2)
- High(er) affinity for O2 (than haemoglobin)
OR
Dissociates oxygen less readily
OR
Associates more readily;
Accept holds O2 at lower ppO2 - Allows (aerobic) respiration when diving/at low(er)
pO2
OR
Provides oxygen when haemoglobin unloaded
OR
Delays anaerobic respiration/lactate production;
Haemoglobin – Animals living at high altitudes shift to left (3)
- high altitudes have a low partial pressure of O2;
- high saturation/affinity of Hb with O2 (at low partial
pressure O2); - sufficient/enough O2 supplied to respiring cells /
tissues;
why does the haemoglobin curve of small animals curve to the right (2)
- Mouse haemoglobin/Hb has a lower affinity for
oxygen
OR
For the same pO2 the mouse haemoglobin/Hb is less
saturated
OR
At oxygen concentrations found in tissue
mouse haemoglobin/Hb is less saturated;
For ‘Hb is less saturated’ accept ‘less oxygen will be
bound to Hb’. - More oxygen can be
dissociated/released/unloaded (for metabolic
reactions/respiration);
Accept ‘oxygen
dissociated/released/unloaded more readily/easily/quick
ly’
why does the haemoglobin curve curve to the right for more active animals
(2)
- Curve to the right so lower affinity / % saturation
(of haemoglobin); - Haemoglobin unloads / dissociates more readily;
- More oxygen to cells / tissues / muscles;
- For greater / more / faster respiration;
Describe three control
measures the
student must use to
reduce the risks
associated with
carrying and using a
scalpel.
- Carry with blade protected / in tray
- Cut away from body;
- Cut onto hard surface;
- Use sharp blade;
- Dispose of used scalpel (blade) as instructed;
Describe Control measures when packing away (2)
- Carry/wash sharp instruments by holding handle
OR
Carry/wash sharp instruments by pointing away (from
body)/down;
Accept for ‘instruments’, a suitable named example, eg.
scalpel - Disinfect instruments/surfaces;
Accept for ‘instruments’, a suitable named example, eg.
scalpel
Accept for ‘disinfect’, sanitise OR use antiseptic - Disinfect hands
OR
Wash hands with soap (and water);
Accept for ‘disinfect’, sanitise OR use antiseptic - Put organ/gloves/paper towels in a (separate)
bag/bin/tray to dispose;
Give the pathway a
red blood cell takes
when travelling in
the human
circulatory system
from a kidney to the
lungs. (3)
- Renal vein;
- Vena cava to right atrium;
- Right ventricle to pulmonary artery;
Name the blood
vessels that carry
blood to the
heart muscle. (1)
Coronary arteries;
what causes the semi-
lunar valve to close (1)
Because pressure in aorta higher than in ventricle;
explain how the
atrioventricular valve
is closed (2)
- ventricle contracts and volume decreases
- pressure (ventricle) increases so higher than pressure
of left atrium;
Explain how an
arteriole can reduce
the blood flow into
capillaries. (2)
- Muscle contracts;
- Constricts/narrows arteriole/lumen;
Describe Artery – Structure and
Function (5)
- Elastic tissue to allow stretching/recoil/ smooths out
flow of blood/maintains pressure; - (Elastic tissue) stretches when ventricles contract OR
Recoils when ventricle relaxes; - Muscle for contraction/vasoconstriction;
- Thick wall withstands pressure OR stop bursting;
- Smooth endothelium reduces friction;
Explain four ways in
which the structure
of the aorta is
related to its
function.
- Elastic tissue to allow stretching / recoil /
smoothes out flow of blood / maintains pressure; - (Elastic tissue) stretches when ventricles contract
OR
Recoils when ventricle relaxes; - Muscle for contraction / vasoconstriction;
- Thick wall withstands pressure OR stop bursting;
- Smooth endothelium reduces friction;
- Aortic valve / semi-lunar valve prevents backflow.
describe type of
circulation in fish (1)
- Single circulatory system
2 chambers/1 ventricle1 atrium - One vein carrying blood towards the heart/ One artery
carrying blood away
Explain how water from tissue fluid is returned to the circulatory system.
(4)
- (Plasma) proteins remain;
Accept albumin/globulins/fibrinogen for (plasma) protein - (Creates) water potential gradient OR
Reduces water potential (of blood); - Water moves (to blood) by osmosis;
- Returns (to blood) by lymphatic system;
Explain
the role of the heart
in the formation of
tissue fluid. (2)
- Contraction of ventricle(s) produces high blood /
hydrostatic pressure; - (This) forces water (and some dissolved
substances) out (of blood capillaries);
High
absorption of salt
from the diet can
result in a higher
than normal
concentration of salt
in the blood plasma
entering capillaries.
This can lead to a
build-up of tissue
fluid.
Explain how. (4)
- (Higher salt) results in lower water potential of
tissue fluid; - (So) less water returns to capillary by osmosis (at
venule end);
OR - (Higher salt) results in higher blood pressure /
volume; - (So) more fluid pushed / forced out (at arteriole
end) of capillary;
High
blood pressure
leads to an
accumulation of
tissue fluid. Explain
how. (2)
- High blood pressure = high hydrostatic pressure;
- Increases outward pressure from (arterial) end of
capillary / reduces inward pressure at (venule) end of
capillary; - (So) more tissue fluid formed / less tissue fluid is
reabsorbed.
Describe and explain Formation and
reabsorption (8)
- At arteriole end high hydrostatic pressure/blood
pressure; - Hydrostatic pressure higher than effect of osmosis;
- Small molecules/named example eg glucose; water
- Forces out;
- Proteins remain in blood/ not removed as they are too
large to leave capillary; - Increasing/giving higher concentration of blood
proteins so proteins lower water potential of blood; - Water/fluid moves back into blood;
- Water moves by osmosis
