| Date | November 2020 | Marks available | 1 | Reference code | 20N.1.HL.TZ0.26 |
| Level | Higher level | Paper | Paper 1 | Time zone | TZ0 / no time zone |
| Command term | Question number | 26 | Adapted from | N/A |
Question
The number of protein-coding genes in the human genome is estimated to be about 20 000, which is much less than the size of the proteome. What is one reason for this?
A. Exons are removed from RNA before translation.
B. There are more types of amino acids than nucleotides.
C. mRNA can be spliced after transcription.
D. Base substitutions occur during transcription.
Markscheme
C
Examiners report
Syllabus sections
- 22M.1.HL.TZ1.27: During modification in eukaryotes, mRNA is spliced. What is splicing of mRNA? A. Separation...
- 18M.1.HL.TZ2.11: How can environmental factors affect the expression of genes? A. By promoting the...
- 22M.1.HL.TZ2.27: Promoters are non-coding regions in DNA. What is the role of a promoter? A. It starts...
- 19M.2.HL.TZ2.2b.ii: Suggest a way methylation may affect tumour cell genes.
- 17M.1.SL.TZ1.1: Which structure found in eukaryotes has a single membrane? A. Nucleus B. Lysosome C....
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17M.1.HL.TZ2.12:
In which process(es) do nucleosomes play a role in eukaryotes?
I. tRNA activation
II. Transcription regulation
III. DNA supercoiling
A. I only
B. II only
C. II and III only
D. I, II and III
- 17N.1.HL.TZ0.26: Some regions of DNA do not code for the production of proteins. What are these regions of DNA...
- 17M.2.HL.TZ1.2a.ii: Nucleosomes help to regulate transcription in eukaryotes. State a chemical modification of a...
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21M.1.HL.TZ2.27:
What is a feature of transcription in the single-celled organism shown in the electron micrograph?
[Source: George E. Palade Electron Microscopy Slide Collection Harvey Cushing/John Hay Whitney Medical Library Yale University Library.]
A. mRNA splicing
B. Removal of introns
C. Codon-anticodon binding
D. Synthesis of RNA in a 5′ to 3′ direction
- 19M.2.HL.TZ2.2b.i: Outline the difference in methylation pattern between tumorous and normal tissue samples.
- 18M.1.HL.TZ2.10: Gene expression in cells is regulated at various stages. During which stage does splicing of...
- 17M.2.HL.TZ2.8c: Explain the control of gene expression in eukaryotes.
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17N.2.HL.TZ0.07b:
Nitrogen is part of many important substances in living organisms.
Distinguish between transcription and translation.
-
21N.2.HL.TZ0.6a:
Draw labelled diagrams to show the structure of RNA nucleotides and how they are linked together to form a molecule of RNA.
-
21N.2.HL.TZ0.6b:
Explain transcription.
