Tutor profile: Robin S.

Describe the process of Polymerase Chain Reaction (PCR).

The process of PCR begins with a high temperature (~95 C) so that the DNA strands denature (separate the two strands). The temperature is then lowered (to ~60 C) so that the added primers can anneal to their target sites on the forward 3' strand and the reverse 5' strand. The temperature is again raised (to ~72 C) in order to initiate the polymerase on both the forward and reverse strands and extend the sequence with dNTPs after the primer. The annealing and extension steps are repeated as cycles causing the PCR products to amplify exponentially. After the amplification cycles the product is used for downstream analysis.

When comparing the mitosis and meiosis cell cycles, what is the major key difference?

The key difference between mitosis and meiosis is that during mitosis there is a conservation of the number chromosome sets, whereas in meiosis the number of chromosome sets is reduced from diploid (2) to haploid (4).

5(x+2) + 3(x-1) = 2x + 1

(5x + 10) + (3x - 3) = 2x + 1 5x + 10 + 3x - 3 = 2x + 1 8x + 7 = 2x + 1 8x - 2x = 1 - 7 6x = -6 x = -1