Final answer:
The percentage of GC in a DNA sequence affects the melting temperature (Tm) as GC pairs are linked by three hydrogen bonds, thus requiring more heat to break apart, leading to a higher Tm. This impacts the success of cloning experiments which rely on DNA's thermal stability.
Step-by-step explanation:
The percentage of GC (guanine-cytosine) in a DNA sequence affects the melting temperature (Tm) because the more GC pairs present, the higher the Tm. This is due to the fact that GC pairs form three hydrogen bonds compared to AT (adenine-thymine) pairs, which only form two. These additional bonds increase the stability of the DNA molecule, requiring more heat to denature the helix.
In the context of cloning experiments, the Tm is critical because it indicates the thermal stability of the DNA. A higher Tm can suggest a more stable template and may therefore affect the efficiency and success of DNA amplification processes, like polymerase chain reaction (PCR), which is an essential step in cloning.
So, in summary, the correct answers to the student's question are (b) the higher the amount of GC, the higher the Tm, and (c) GC-rich sequences will have a higher Tm because they have more hydrogen bonds.