Genetics

DNA polymerases are the enzymes that replicate DNA in living cells. They do this by adding individual nucleotides to the 3-prime hydroxl group of a strand of DNA. The process uses a complementary, single strand of DNA as a template.

The energy required to drive the reaction comes from cutting high energy phosphate bonds on the nucleotide-triphosphate's used as the source of the nucleotides needed in the reaction.

Chromosome

The Hardy-Weinberg equation describes allele frequencies in populations. It predicts the future genetic structure of a population the way that Punnett Squares predict the results of an individual cross. The equation calculates allele frequencies in non-evolving populations. It is based on the observation that in the absence of evolution, allele frequencies in large randomly breeding populations remain stable from generation to generation.

A Punnett Square^* shows the genotype^*s two individuals can produce when crossed. To draw a square, write all possible allele^* combinations one parent can contribute to its gametes across the top of a box and all possible allele combinations from the other parent down the left side. The allele combinations along the top and sides become labels for rows and columns within the square.

DNA^* is the information molecule of the cell.

Patterns of genetic inheritance obey the laws of probability. In a monohybrid cross, where the allele^*s present in both parents are known, each genotype^* shown in a Punnett Square^* is equally likely to occur. Since there are four boxes in the square, every offspring produced has a one in four, or 25%, chance of having one of the genotypes shown.