| Date | May 2019 | Marks available | 1 | Reference code | 19M.3.SL.TZ2.17 |
| Level | Standard level | Paper | Paper 3 | Time zone | Time zone 2 |
| Command term | State | Question number | 17 | Adapted from | N/A |
Question
The diagram shows metabolic pathways for lactate in humans.
[Source: © International Baccalaureate Organization 2019]
State the name of the blood vessel through which lactate from muscles reaches the liver
Compare and contrast the possible metabolic pathways for lactate in hepatocytes and in mitochondria-rich tissue.
List two functions of hepatocytes other than regulating lactate levels in the blood.
1.
2.
Markscheme
hepatic artery ✔
a. both produce pyruvate «from lactate»
OR
both produce CO2 and H2O «via acetyl CoA» ✔
b. hepatocytes produce glucose from lactate but mitochondria-rich cells cannot ✔
OWTTE – eg: “only hepatocytes produce glucose” would be acceptable.
a. detoxification ✔
b. production/secretion of bile ✔
c. conversion of cholesterol to bile salts ✔
d. production of plasma proteins ✔
e. nutrient storage ✔
f. glucose regulation «in blood» ✔
g. other function «eg deamination/transamination, conversion of ammonia to urea» ✔
Only two functions are required.
If more than two functions are given, mark only the first two listed.
Examiners report
The data showed possible metabolic pathways for lactate in humans. In (a) many candidates wrongly answered the hepatic portal vein.
Part (b) and (c) were well answered, the main error was confusing the hepatocytes with the Kupffer cells.
Part (b) and (c) were well answered, the main error was confusing the hepatocytes with the Kupffer cells.
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.
- 16N.3.HL.TZ0.23: Explain, using an oxygen dissociation curve, how hemoglobin supplies oxygen to respiring...
-
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.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.
