Polymerase chain reaction (PCR) is a technique used to generate thousands to millions of copies of a specific segment of DNA. There are three major steps to PCR. Denaturation occurs when heat separates the original DNA strand. Annealing follows, in which the DNA is cooled and primers bind to each separated strand. The final step is extension, in which DNA polymerase adds nucleotides to the 3' end of each primer. These steps are repeated for each PCR cycle.

Nucleotides are the monomers that make up nucleic acids. They are composed of a five-carbon sugar, a nitrogenous base, and a phosphate group. In building the polymer nucleic acid chain, the sugar and phosphate of one nucleotide align with those of another to build the phosphate-sugar backbone, while the nitrogenous bases will form hydrogen bonds across the helix to link two chains of nucleotides together. Phosphate groups carry negative charge; this gives the cell nucleus an overall negative charge and can be used to generate electrochemical gradients across the nuclear membrane.

Carboxylic acids are found in amino acids, and are not present in nucleic acids.

Adenosine triphosphate contains an adenine group, a ribose sugar, and three phosphates. ATP is known as the energy molecule since there is a lot of potential energy stored in the bonds between each of the three phosphate groups.

Hydrogen bonds form between electronegative atoms such as nitrogen and hydrogen atoms on their complementary bases between the DNA backbones. Adenine and thymine make two hydrogen bonds, while cytosine and guanine made three hydrogen bonds. Phosphodiester bonds keep the DNA backbone bonded together. Ionic and covalent bonds are too strong to bond the two antiparallel strands together since the strands must be separated during DNA synthesis. Hydrogen bonds are the perfect bond since they are weak individually, but collectively very strong.

Promoters help the transcription machinery and associated proteins (like DNA helicase) find the correct spot to start transcription and facilitate opening of the DNA. When transcription takes place, DNA helicase must open up or "unzip" the double helix. Te fewer the hydrogen bonds the easier it is for DNA to be denatured. Adenine and thymine only have two hydrogen bonds between them, while cytosine and guanine have 3. Thymine and adenine are the best candidates for promoter sequences based on their fewer number of hydrogen bonds which is evidenced by a common promoter sequence called "TATA box".

Earth's early atmosphere contained carbon,  (methane),  (ammonia), and , but no oxygen. 

RNA stands for ribonucleic acid, and each RNA nucleotide contains one phosphate, one nitrogenous base (either adenine, uracil, cytosine, or guanine), and one ribose sugar. RNA does not contain a deoxyribose sugar as seen in DNA.

Nucleotides are linked together to form nucleic acids by bonds between the phosphate groups and ribose sugars. A phosphate group is bonded the 5' carbon of one ribose and the 3' carbon of the next ribose, leading to the 5' to 3 directionality of DNA.

A nucleotide is made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base.  Lipids consist of a glycerol and fatty acid chains