| Date | May 2022 | Marks available | 2 | Reference code | 22M.2.SL.TZ1.2 |
| Level | Standard level | Paper | Paper 2 | Time zone | Time zone 1 |
| Command term | Explain | Question number | 2 | Adapted from | N/A |
Question
The diagrams represent the structure of a protein before and after it has become denatured.
[Source: Dean Williams, L., 2019. Molecular Interactions. [online] Available at: https://ww2.chemistry.gatech.edu/~lw26/
structure/molecular_interactions/mol_int.html [Accessed 20 August 2019].]
State how many different types of amino acid there are, which can become part of a polypeptide when mRNA is translated.
Outline one cause of denaturation in proteins.
Explain how denaturation affects the activity of an enzyme.
Markscheme
20;
- increase in temperature/heat;
- change of pH;
- salt;
- heavy metals;
- changes the shape of the (active site) of the enzyme;
- substrate would be unable to attach to the enzyme/active site;
- slows the enzyme activity / prevents reaction/catalysis from proceeding;
Examiners report
Amazingly, most candidates missed gaining the mark for this question: a huge variety of incorrect numbers appeared, "4" was most frequent. Many candidates seemed to confuse the 4 nucleotide bases with the 20 amino acids.
Most candidates answered these questions about enzymes either really well or very poorly. Some erroneous answers mistook the active site as being separate to the enzyme or part of the substrate. Another problem had to do with temperature as a denaturant. Lowering the temperature does not denature the enzyme, though it may slow the reaction down. The candidate needed to say increased or hot temperature to gain a mark.
Syllabus sections
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22M.1.HL.TZ2.6:
The diagram shows the structure of the protein CXCL12.
[Source: Lu, J., Chatterjee, M., Schmid, H. et al. CXCL14 as an emerging immune and inflammatory modulator.
J Inflamm 13, 1 (2016). https://doi.org/10.1186/s12950-015-0109-9 Distributed under the terms of the
Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/).]Which chemical group is found at X?
A. NH2
B. NOH
C. COH
D. COOH
- 17N.1.HL.TZ0.05: Which of the molecules contain peptide bonds or are sugar molecules?
- 16N.1.SL.TZ0.7: The diagram shows a molecular structure. Which type of molecule is shown? A. Amino acidB....
- 17M.2.SL.TZ2.5a: Draw a molecular diagram of an amino acid to show its general structure.
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21N.1.HL.TZ1.6:
The image shows the structure of the protein hemoglobin
[Source: Hemoglobin molecule, Microbiology ID: e42bd376-624b-4c0f-972f-e0c57998e765@4.4 OpenStax Microbiology
https://cnx.org/contents/5CvTdmJL@4.4 and https://commons.wikimedia.org/wiki/File:OSC_Microbio_07_04_
hemoglobin.jpg Licensed under a Creative Commons Attribution 4.0 International License,
https://creativecommons.org/licenses/by/4.0.]What level of protein structure bonds the α and β chains together?
A. Primary
B. Secondary
C. Tertiary
D. Quaternary
- 17N.1.SL.TZ0.06: Which molecule could be hydrolysed into amino acids?
- 22M.2.SL.TZ1.2a: State how many different types of amino acid there are, which can become part of a...
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18M.1.SL.TZ1.9:
Which protein has the highest tensile strength (ability to resist breaking when stretched)?
A. Cellulose
B. Actin
C. Spider silk
D. Albumin
- 18M.1.SL.TZ2.10: Which description matches the protein?
- 17M.3.SL.TZ2.2c: State two conditions that should be kept constant in both experiments.
- 17M.3.SL.TZ2.2b: Suggest two changes occurring in the reaction vessel that could be used to indicate...
- 22M.1.SL.TZ2.9: People who suffer from night blindness cannot see well at night because their retinal cells...
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19M.1.SL.TZ1.9:
The graph shows the results of an investigation into the activity of turnip peroxidase. The accumulation of the product of the reaction catalysed by the enzyme is shown at different pH values.
[Source: © International Baccalaureate Organization 2019]
Based on the data in the graph, what is most probably the optimum pH for turnip peroxidase?
A. Between 3 and 5
B. Between 10 and 11
C. Between 7 and 8
D. Between 9 and 10
- 19N.1.HL.TZ0.6: What is a proteome? A. The genes that code for all the proteins in the ribosome B. The...
- 17M.1.SL.TZ2.27: The bacterium Neisseria gonorrhoeae causes infections related to the human reproductive...
- 17M.3.SL.TZ2.2a: Determine the optimum pH and temperature of keratinase.
- 17M.1.SL.TZ1.21: Cladograms can be created by comparing DNA or protein sequences. The cladogram on the left is...
- 17M.1.SL.TZ1.15: How does the proteome of a species contain a larger number of proteins than genes that code...
- 21N.2.SL.TZ0.2b: Outline the specific functions of three named proteins.
- 17M.2.HL.TZ1.1f.ii: Suggest a reason for the greater expression of the gene for the urea transporter after an...
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21M.2.SL.TZ2.3c:
State the genus of the plant where this Rubisco is found.
- 21M.2.SL.TZ1.6a: Outline the structure of proteins.
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21M.2.SL.TZ2.3d:
Outline one factor that could affect the activity of Rubisco.
- 17M.2.HL.TZ1.6a: Describe the functioning of immunoglobulins.
- 21M.2.HL.TZ2.6c: The enzyme Rubisco is used in carbon fixation during photosynthesis. Identify four other...
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21M.2.SL.TZ1.6c:
Outline the range of functions of proteins in cells.
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21M.2.SL.TZ2.3a:
State one function of Rubisco.
- 17M.2.SL.TZ1.1c: Estimate how much smaller drilled oysters raised in seawater at a high CO2 concentration were...
- 22M.2.SL.TZ1.2b: Outline one cause of denaturation in proteins.
- 19M.1.SL.TZ1.8: What is found in insulin molecules? A. Phosphates B. Nucleotides C. Peptide bonds D....
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19M.1.HL.TZ2.9:
The graph shows the activity of an enzyme at different temperatures.
[Source: © International Baccalaureate Organization 2019]
What does the dashed line in the graph represent?
A. Increasing temperature increases substrate concentration.
B. Increasing temperature affects the active site.
C. Increasing temperature increases the rate of reaction.
D. Increasing temperature decreases the movement of particles.
- 17M.1.SL.TZ1.9: The most abundant structural protein in the human body is found in ligaments and skin. What...
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19M.1.SL.TZ2.8:
Which statement correctly describes genome and proteome?
A. Only the genome but not the proteome can be analysed using gel electrophoresis.
B. The genome and the proteome are the same in all tissues in an organism.
C. In cells of different tissues, the genome is the same while the proteome varies.
D. Only mutations in the proteome but not in the genome cause any variability.
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18M.2.HL.TZ1.6c:
Hydrogen bonds can exist both within and between molecules in living organisms and have an impact on their structure and function. Explain the importance of hydrogen bonding for living organisms.
- 20N.1.SL.TZ0.8: The genetic code is shown. In a coding gene, the DNA triplet in the transcribed strand is...
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21N.2.HL.TZ0.8a:
Outline the process of protein denaturation.
- 19M.1.HL.TZ2.16: Which protein is identified with its function?
