Explain why three-base codons are needed and distinguish code degeneracy from its near universality.
Tę umiejętność sprawdza 7 zadań wzorowanych na arkuszach IB z lat 2022–2026.
An invented time-scaled tree compares ten related beetle species. (i) Identify the two species with the most recent divergence and give a reason. (ii) Suggest why comparing DNA base sequences can distinguish relationships that are missed by comparing amino…
Biological functions depend on molecular organization and coordination between body systems. (a) Describe how codons determine polypeptide structure. (b) Outline how photosystem structure supports its function. (c) Explain how blood pH can fall during activity…
What consequence follows from several codons specifying the same amino acid? A. Some substitutions leave the amino-acid sequence unchanged B. Every codon specifies several amino acids C. A ribosome can translate a codon without tRNA D. Every substitution…
Which row demonstrates degeneracy of the genetic code? Row | mRNA codons | Encoded amino acids P | AAA GCU AAA | Lys–Ala–Lys Q | AUG UGG GAA | Met–Trp–Glu R | UCU GGA UCC | Ser–Gly–Ser S | UAC GAC AAC | Tyr–Asp–Asn A. P B. Q C. R D. S
How many mRNA bases specify the amino acids in this model peptide? Count only bases in the amino-acid codons, excluding a stop codon and untranslated regions. A. 40 B. 80 C. 60 D. 20
Suggest why the corresponding DNA sequences could differ more than these amino-acid sequences.
Which numerical relationship illustrates degeneracy in the standard genetic code? A. There are fewer codons than the four nucleotide types B. There are more sense codons than encoded amino-acid types C. Every codon specifies two different amino acids at once…
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