| Date | November 2019 | Marks available | 1 | Reference code | 19N.1.HL.TZ0.29 |
| Level | Higher level | Paper | Paper 1 | Time zone | TZ0 / no time zone |
| Command term | Deduce | Question number | 29 | Adapted from | N/A |
Question
The grey line in each of the graphs below represents the rate of reaction catalysed by an uninhibited enzyme as substrate concentration is increased.
Which graph shows expected results if a competitive inhibitor was added to the reaction?
[Source: © International Baccalaureate Organization 2019]
Markscheme
B
Examiners report
Syllabus sections
- 18N.1.HL.TZ0.28: The graph shows the effect of substrate concentration on the rate of an enzyme-catalysed...
- 18N.2.HL.TZ0.1c: State the highest concentration of cotinine in the urine, giving the units.
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21N.1.HL.TZ1.29:
Some bacteria can synthesize the amino acid isoleucine from threonine, a process involving five enzymes (E1 to E5) and four intermediary products (P, Q, R and S). The production of isoleucine is controlled by end-product inhibition.
Which statement describes this end-product inhibition?
A. If isoleucine accumulates, it inhibits the production of P.
B. End-product inhibition causes a build-up of intermediary products.
C. Isoleucine inhibits E5, so no more isoleucine is produced.
D. Isoleucine affects the structure of threonine.
- 17M.1.HL.TZ1.31: The graph shows the rate of an enzymatic reaction versus the substrate concentration, in the...
- 17M.1.SL.TZ1.1: Which structure found in eukaryotes has a single membrane? A. Nucleus B. Lysosome C....
- 17M.2.HL.TZ2.2a: The sketch shows the relationship between the reaction rate and substrate concentration in...
- 16N.1.HL.TZ0.29: The graph shows an example of an enzyme-catalysed reaction. What does the curve labelled X...
- 22M.1.HL.TZ1.29: The graph shows the effect of increasing substrate concentration on the rate of an...
- 16N.2.HL.TZ0.3b: Outline the importance of enzymes to metabolic processes.
- 18N.1.HL.TZ0.31: Which is a reduction reaction? A. ATP changing to ADP B. Maltose changing to glucose C. ...
- 18N.2.HL.TZ0.1d.i: Deduce, with a reason, whether the concentrations of cotinine and NNAL-Gluc would be higher...
- 20N.1.HL.TZ0.29: Sulfanilamide inhibits an enzyme that catalyses a reaction involving PABA, an intermediate in...
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21M.2.HL.TZ1.8c:
Explain the factors that affect the rate of enzyme-controlled reactions in cells.
- 18N.2.HL.TZ0.1d.ii: Suggest one advantage of using the urine concentration of cotinine rather than NNAL-Gluc to...
- 19M.2.HL.TZ1.7a: Outline the roles of helicase and ligase in DNA replication.
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19M.1.HL.TZ1.29:
The first enzyme in the metabolic pathway that produces isoleucine is threonine deaminase. Which graph illustrates the relationship between threonine deaminase activity and threonine concentration?
[Source: © International Baccalaureate Organization 2019]
- 19M.2.HL.TZ1.5b: Outline the control of metabolism by end-product inhibition.
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21N.2.HL.TZ0.8c:
Distinguish between competitive and non-competitive enzyme inhibition.
- 18M.2.HL.TZ1.5d: The graph shows energy levels throughout an uncatalysed reaction. Draw a curve to show how...
- 18M.1.HL.TZ2.13: Metabolic pathways are dependent on enzyme-catalysed reactions. Which term corresponds with...
