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DNA fragments begin in wells near the negative electrode of the gel shown. Which fragment would move farthest towards the positive electrode during the same run? A. 7 kb, positively charged B. 3 kb, negatively charged C. 9 kb, negatively charged D. 1 kb,…
A physiology course examines how biological systems preserve stable information and internal conditions. (a) Explain mechanisms that reduce copying errors during DNA replication. (b) Describe regulation of blood glucose in humans. (c) Explain why extracellular…
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…
Molecular binding underlies both communication and metabolic regulation. (a) Describe complementary molecules in cell-signalling systems, with examples. (b) Explain causes and consequences of changes to enzyme active sites. (c) Outline how reversible changes…
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
Why does a PCR protocol use two designed DNA primers? A. They identify the ends of the target and provide sites for extension B. They digest all DNA outside the target C. They prevent complementary strands from ever pairing D. They replace the proofreading…
Genetic information helps explain early life and guide present-day conservation. (a) Describe RNA structure and evidence supporting an RNA-first stage of early life. (b) Describe uses of DNA-sequence analysis in biodiversity conservation. (c) Explain causes…
A copied DNA segment changes from GATCCGTAAGC to GATCTGTAAGC. Which mutation class describes this change? A. Deletion B. Insertion C. Whole-genome duplication D. Base substitution
Researchers make mice lacking a functional tumour-suppressor gene. Which use of this model is appropriate? A. Testing a candidate treatment against tumours developing in the model B. Obtaining an intact copy of the deleted gene from those cells C. Proving that…
A virus can make new particles only after entering a suitable living host cell. How is this dependence classified? A. Obligate intracellular parasitism B. Facultative saprotrophy C. Photoautotrophy D. Free-living predation