IB Questionbank

Updates to Questionbank

User interface language: English | Español

Date	May 2015	Marks available	3	Reference code	15M.3.SL.TZ2.18
Level	Standard level	Paper	Paper 3	Time zone	Time zone 2
Command term	State	Question number	18	Adapted from	N/A

Question

State the role of Rhizobium, Nitrobacter and Azotobacter in the nitrogen cycle.

Rhizobium: .....................................................................
Nitrobacter: .....................................................................
Azotobacter: .....................................................................

[3]

a.

Explain the production of methane from biomass.

[4]

b.

Markscheme

a. Rhizobium: nitrogen fixation;
b. Nitrobacter: oxidizes/changes nitrites to nitrates;
c. Azotobacter: nitrification / bind atmospheric nitrogen / nitrogen fixation;

a.

a. anaerobic digestion of biodegradable material;
b. fermentation (of carbohydrates) by bacteria;
c. methanogens produce methane;
d. methane/biogas used as energy;
e. waste products used as fertilizer;
f. CO₂ produced (as a by-product);

b.

Examiners report

N/A

a.

Some students gave comprehensive explanations of the production of methane from biomass. Most students scored at least one point.

b.

Syllabus sections

Option C: Ecology and conservation » Option C: Ecology and conservation (Additional higher level topics) » C.6 Nitrogen and phosphorus cycles

Show 34 related questions

17N.3.HL.TZ0.18: Discuss the causes and consequences of eutrophication.
17M.3.HL.TZ2.15d: A coat of algae builds up on coral reefs as a consequence of eutrophication. Explain the...
17M.3.HL.TZ1.16b: The percentage of phosphorus in an ecosystem that is recycled per year is in most cases very...
17M.3.HL.TZ1.16a: Some scientists estimate that available phosphorus reserves in the Earth will be completely...
16N.3.HL.TZ0.18: Discuss how crop plants obtain the phosphorus that they need to grow and whether the supply...
16N.3.SL.TZ0.14a: Outline the trend in the number of people with malaria during the period when the use of...
16M.3.HL.TZ0.14c: Suggest one reason for ammonium levels in the interior of the forest being lower than the...
16M.3.HL.TZ0.14b: List two sources of the ammonium in the forest soils apart from deposition in rainfall.
16M.3.HL.TZ0.14a: Outline the procedure that was most likely used by the researchers to decide where to take...
15N.3.SL.TZ0.17b: Outline the process of nitrogen fixation by a named free-living bacterium.
15N.3.HL.TZ0.8c: Outline the process of nitrogen fixation by a named free-living bacterium.
13M.3.SL.TZ1.18b: Explain the consequences of releasing raw sewage and nitrate fertilizer into rivers.
13M.3.SL.TZ2.18a: State one soil condition that favours denitrification.
11M.3.HL.TZ1.8b: State the role of Rhizobium and Nitrobacter in the nitrogen cycle. Rhizobium: ...
11M.3.SL.TZ2.18a: State one condition that favours denitrification.
11M.3.SL.TZ2.18b: Explain the consequences of releasing raw sewage and nitrate fertilizer into rivers.
12M.3.HL.TZ1.10a (ii): Deduce the tank in which the level of mercury accumulation in Daphnia was lowest.
12M.3.HL.TZ1.10c: Using the data, suggest reasons for the relationship between phosphorus concentration in the...
12M.3.HL.TZ1.10a (i): Deduce the tank in which the quantity of algae was highest.
12M.3.HL.TZ1.10b: Outline the relationship between phosphorus concentration in the water and the accumulation...
12M.3.SL.TZ1.7a: Estimate the difference between the lowest and highest rates of release of CO2 from the soil...
12M.3.SL.TZ1.7c (i): Describe the relationship between rates of nitrogen addition and release of CO2 from soil in...
12M.3.SL.TZ1.7b: Suggest one process occurring in tree roots that could cause the release of CO2 from the soil.
12M.3.SL.TZ1.7c (ii): Suggest a reason for this relationship.
12M.3.SL.TZ1.7d: Compare the effects of the nitrogen addition treatments on the hardwood and softwood areas of...
12M.3.SL.TZ1.17b: Denitrification is part of the nitrogen cycle. Outline the conditions that favour...
12M.3.SL.TZ2.18c (i): State the role of Rhizobium in the nitrogen cycle.
10M.3.SL.TZ1.23c: Outline the consequences of releasing nitrate fertilizer into rivers.
10M.3.SL.TZ1.23a: Indicate the processes occurring at A and B. A:...
10M.3.SL.TZ1.23b (i): Draw an arrow to indicate where in the cycle Azotobacter plays a role.
10M.3.SL.TZ1.23b (ii): State the role of Nitrobacter in this cycle.
11N.3.SL.TZ0.16a: The diagram below shows the nitrogen cycle. Using the letter X, label where the process of...
10N.3.HL.TZ0.8a(ii): Outline the conditions that favour denitrification.
10N.3.HL.TZ0.8a(i): State two nitrogen-fixing bacteria.

Hide related questions