DNA nucleotides and the order of information
הוצג| English | משמעות |
|---|---|
| nucleotide/ˈnjuːklɪɒtaɪd/ | נוקלאוטיד |
| base sequence/beɪs ˈsiːkwəns/ | רצף בסיסים |
What would explain this observation?
- Four kinds of base can encode many different sequences. The information is in their order, not simply how many different base letters exist.
Build the model
- DNA is a polymer made of repeating nucleotide 核苷酸 units.
- Each nucleotide contains a sugar, a phosphate group and one of four bases: A, C, G or T.
- The long strands contain alternating sugar and phosphate sections, with a base attached to each sugar.
- The molecule has two strands arranged as a double helix.
- nucleotide: A DNA unit containing sugar, phosphate and a base.
- base sequence 碱基序列: The order of bases along a DNA strand.
What distinguishes the four DNA nucleotide kinds in this model?
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
All four nucleotides share the same sugar-phosphate framework; they differ only in the attached base - A, T, G or C. The base order is what carries the information.
Match each technical term to its precise meaning.
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- In the specified simple model, a sequence of three bases codes for a particular amino acid.
- The order of bases controls the order in which amino acids are assembled into a protein.
- Moving the same letters into a different order can change the information.
- Complementary pairing and the simple synthesis mechanism belong to the Higher lesson, so do not demand those details in a common-tier task.
In the lab: Identify sugar, phosphate and base in a supplied nucleotide diagram and trace repeating units along a strand. Interpret a diagram rather than memorising an elaborate drawing: reproducing the DNA structure diagram is not required. Use a teacher-supplied triplet-to-amino-acid key when decoding a fictional sequence; no memorised genetic-code table is needed.
Which two habits make the investigation or model in this case more defensible?
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
Stating the conditions and assumptions lets others repeat the work exactly, and recording the supporting evidence lets them check the conclusion. Hiding disagreeing results removes the evidence that could challenge a wrong conclusion, and one measurement can never establish a wider claim.
Work from known quantities
- Known: a fictional coding sequence has 27 bases arranged into complete three-base groups.
- It contains 27/3 = 9 groups in this simplified exercise.
- The prompt excludes start and stop details.
- Real interpretation requires information about which region is coding; dividing every base in a whole chromosome by three is not a valid protein-length calculation.
Your turn: A fictional sequence contains 36 bases in complete three-base groups. Find the number of groups.
A fictional sequence contains 36 bases in complete three-base groups. Find the number of groups.
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
The result is 12 groups. Known: 36 bases in complete three-base groups. Number of groups = 36/3 = 12 groups. Real protein-length calculations need to know the coding region; not every base codes.
Check the conclusion and its limits
- A nucleotide is not just its base.
- Sugar and phosphate form the strand framework, while base order carries the sequence information.
- Three-base grouping here is an explicit classroom model, not a promise that all genomic DNA becomes protein.
Not true: A DNA nucleotide consists only of an amino acid. A nucleotide is built from a phosphate, a sugar and a base - no amino acid is part of it. Amino acids are the monomers of proteins, not of DNA.
- DNA is a polymer made of repeating nucleotide units.
- In the specified simple model, a sequence of three bases codes for a particular amino acid.
- Watch for: A nucleotide is not just its base.
A nucleotide is built from a phosphate, a sugar and a base - no amino acid is part of it.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
True. A nucleotide is built from a phosphate, a sugar and a base - no amino acid is part of it. Amino acids are the monomers of proteins, not of DNA.
A DNA unit containing sugar, phosphate and a base: write the technical term.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
nucleotide means A DNA unit containing sugar, phosphate and a base.