pack 6b transport in the blood incomplete

Question 1

red blood cells adapted to its function

Answer 1

1) rbc are very small
- this small size means every haemoglobin molecule is near to the cells plasma membrane
+ short diffusion pathway
+ large sa to vol ratio

2) red blood cells are shaped like a biconcave disc
- increase the SA to vol ration o2 can diffuse quickly
- dent also provides a shorter diffusion pathway

3) red blood cells have no organelles
- allows RBC to carry much more haemoglobin
- allows for more o2 to bind

Question 2

tissue fluid use

Answer 2

• provides cells with water, oxygen and glucose
• essential for the efficient exchange of materials

Question 3

formation of tissue fluid

Answer 3

1) at the arteriole end of the capillaries, the hydrostatic pressure is high due to the contraction of the left ventricle

2) soluble plasma proteins in the blood reduces the water potential of the blood, creating a water potential gradient, which exerts a pulling force

3) the hydrostatic pressure is higher than the opposing water potential gradient

4) as a result, water and solutes are forced out of the blood through the pores in the capillary walls and this forms the tissue fluid

5) freshly formed tissue fluid has a high concentration of oxygen, glucose and mineral ions needed by the cells

Question 4

return of tissue fluid

Answer 4

1) the larger proteins remain inside the capillary

2) together with the loss of fluid, the hydrostatic pressure of the blood at the venule end of the capillary is low, while the water potential pressure of the tissue fluid is high

3) as a result there is a large, inward osmotic pull, which is now greater than the outward hydrostatic pressure

4) consequently water is drawn back into the capillary by osmosis down a water potential pressure at the venule end

5) waste products diffuse out of the cells into the tissue fluid and then into capillaries along with the water at the venule end

6) the surplus fluid drains into lymphatic vessels that eventually return it to the blood via the thoracic duct in the neck

Question 5

what is haemoglobin

Answer 5

haemoglobin is the blood pigment that has a high affinity for oxygen and readily load oxygen where oxygen concentration are high and unloads oxygen where oxygen concentrations reach a low concentration

Question 6

what kind of protein is haemoglobin

Answer 6

conjugated, with quaternary structure

Question 7

what is haemglobin binded with oxygen called

Answer 7

oxyhaemoglobin

Question 8

cooperative binding

Answer 8

• binding of the first o2 changes teritary/ quaternary structure of haemoglobin
• uncovers the second binding site therefore the next oxygen can bind more easily

Question 9

different forms of haemoglobin

Answer 9

• evolved and these are related to the environmental conditions in which animals e.g. altitude, temp, oxygen availability

Question 10

high affinity haemoglobin

Answer 10

• usually in organisms that live in low po2 environments (high altitude)
• haemoglobin loads oxygen more readily in the lungs
• curve shifts to the left
• haemoglobin is more saturated at any given po2

Question 11

low affinity haemoglobin

Answer 11

• usually in organisms that have a high metabolic rate ( small mammals with large sa: vol ratio and high heat loss
• haemoglobin unloads oxygen more readily at tissues for respiration
• haemoglobin has a reduced saturation at any given po2

Question 12

the bohr effect - exercise

Answer 12

• for many animals, the dissociation curve for haemoglobin is influenced by temp, pH, carbon dioxide concentration
• an increase in temp, acidity and carbon dioxide concentration, displaces the curve to the right = bohr effect
• the significance of the bohr effect is that it facilitates delivery of oxygen to the tissues - aerobic respiration