| Date | November 2016 | Marks available | 6 | Reference code | 16N.3.HL.TZ0.23 |
| Level | Higher level | Paper | Paper 3 | Time zone | TZ0 / no time zone |
| Command term | Explain | Question number | 23 | Adapted from | N/A |
Question
Explain, using an oxygen dissociation curve, how hemoglobin supplies oxygen to respiring tissues and how the Bohr shift increases the supply.
Markscheme
How hemoglobin supplies oxygen to respiring tissues
a. properly labelled axes showing % saturation hemoglobin and partial pressure of oxygen
b. correct/sigmoid shape of «normal» oxygen dissociation curve
Do not accept concave curves. Curve should start at origin.
c. tissues use O2 for «cellular» respiration thus lowering pO2 at tissue level
OR
respiring tissues produce CO2
d. O2 dissociates more at lower pO2 from Hb «than at higher pO2» thus providing O2 to «respiring» tissues/OWTTE
How Bohr shift increases the supply
e. CO2 is converted to hydrogen carbonate ions/HCO3− and H+
f. increase in H+ lowers blood pH
g. H+ combines with Hb / conformational change in Hb «in red blood cell» freeing some O2
h. shifts the oxygen dissociation curve to the right «Bohr shift»
OR
shift to the right shown on diagram labelled Bohr shift
i. oxygen dissociation curve steeper at lower pO2 «corresponding to respiring tissues»
j. lowers the affinity of hemoglobin for oxygen
k. means less oxygen can be carried for same pO2 «as normal»
OR
«even» more oxygen available for respiring tissues for same pO2
Accept any of the marking points in a clearly annotated diagram. Values not required.
Examiners report
Syllabus sections
- 17M.3.SL.TZ1.19: The diagram below shows the liver and main vessels associated with it. Suggest advantages...
- 22M.1.HL.TZ1.40: What is the role of HCG in early pregnancy? A. It prevents the degeneration of the corpus...
- 17M.3.SL.TZ2.20c: Outline the fate of the iron from the erythrocytes.
- 17M.3.HL.TZ1.22: Explain the process of erythrocyte and hemoglobin breakdown in the liver.
- 16N.3.HL.TZ0.21b: Describe how the liver regulates nutrient levels.
- 18M.3.SL.TZ1.17a: The liver receives blood from the digestive system via the hepatic portal vein as...
- 17M.1.SL.TZ1.10: The graph shows the effect of increasing the substrate concentration on the rate of an...
- 18N.3.SL.TZ0.19a.i: Identify cell X shown in the diagram.
- 18N.3.HL.TZ0.18b: Explain how components of bile are produced by the liver.
- 18N.3.SL.TZ0.19a.ii: Outline the role of the cell in recycling iron in the body.
- 17M.3.SL.TZ2.20b: Describe the breakdown of erythrocytes by liver cells.
- 17N.3.SL.TZ0.18a.i: Identify the blood vessel labelled B.
-
18M.3.HL.TZ1.20a.ii:
Outline the circulation of blood through liver tissue.
-
17N.3.SL.TZ0.18a.ii:
Outline the function of the blood vessel labelled B.
- 18M.3.HL.TZ2.21d: Outline the stages involved in the recycling of erythrocytes by the liver.
- 17N.3.HL.TZ0.21a.i: Jaundice causes a yellow discolouration of the skin, mucous membranes and sclera of the eyes....
-
17N.3.HL.TZ0.21b:
Distinguish between the structure of liver sinusoids and capillaries.
-
20N.3.SL.TZ0.18a.ii:
Identify the blood vessel labelled Y which brings blood from the intestines.
-
18M.3.HL.TZ1.20a.i:
The diagram shows the liver and its main blood vessels.
[Source: VectorStock]
Label the hepatic portal vein bringing blood to the liver.
- 16N.3.SL.TZ0.18b: Explain the importance of bilirubin in the onset of jaundice.
-
18M.3.SL.TZ2.18:
Explain the stages involved in the recycling of erythrocytes by the liver.
-
20N.3.SL.TZ0.18a.i:
Identify the phagocyte labelled X.
- 19N.3.SL.TZ0.18a: Explain how materials from red blood cells are recycled by the liver.
- 19N.3.HL.TZ0.20b.ii: Outline one other function of the liver.
-
18M.3.SL.TZ1.17b:
Outline how the liver recycles the components of red blood cells.
- 18N.3.SL.TZ0.19b: Explain reasons for the dual blood supply to the liver.
- 18N.3.HL.TZ0.18a: State the organ in the digestive system where this process is taking place.
-
20N.3.SL.TZ0.18b:
Explain the function of hepatocytes in protein metabolism.
- 20N.3.SL.TZ0.18c: Compare and contrast the structure of sinusoids and capillaries.
- 19N.3.HL.TZ0.20b.i: Describe the breakdown of hemoglobin in the liver.
-
16N.3.SL.TZ0.18a:
The cell labelled X is only found in the liver and is associated with the wall of a sinusoid.
(i) Identify cell X.
(ii) Outline the function of cell X.
- 17M.3.SL.TZ2.20a: State the name of the cells that perform the breakdown of erythrocytes in the liver.
- 18N.3.HL.TZ0.18c: Outline a function of fats in the body.
- 19N.3.SL.TZ0.18b: State a cause and a consequence of jaundice. Cause: Consequence:
- 18M.3.HL.TZ1.20b: Explain the breakdown of hemoglobin in the liver.
-
19M.3.SL.TZ2.17c:
List two functions of hepatocytes other than regulating lactate levels in the blood.
1.
2.
-
17N.3.SL.TZ0.18b:
Distinguish between the structure of liver sinusoids and capillaries.
- 19M.3.SL.TZ1.17c: Excess nutrients absorbed in the intestine can be stored. State one example of a nutrient...
-
19M.3.SL.TZ2.17b:
Compare and contrast the possible metabolic pathways for lactate in hepatocytes and in mitochondria-rich tissue.
-
19M.3.SL.TZ2.17a:
State the name of the blood vessel through which lactate from muscles reaches the liver
- 19M.3.SL.TZ1.17b: State one feature in the diagram that identifies the structure as a sinusoid.
- 19M.3.SL.TZ1.17a: List the two blood vessels that supply the sinusoids. 1. 2.
- 17M.3.HL.TZ1.21b.ii: Explain how the increase in CO2 concentration affects the release of oxygen to respiring cells.
- 19N.2.HL.TZ0.1h: Using all the data, discuss whether inoculating mice with the antigen to B. burgdorferi could...
- 19N.3.HL.TZ0.20a: Describe the relationship between age and liver transplants due to cancers.
-
17N.3.HL.TZ0.21a.ii:
Explain how the normal production of bile pigments changes with the development of jaundice.
-
18N.3.HL.TZ0.18e:
In order to compare the absorption of fat and of glucose in the digestive system, state in the table, using yes or no, whether the processes occur.
