It is a type of lipid that is in all aminal cells. It can be produced by the body, but is mostly taken in. Since animals make cholesterol, the easiest way for cholesterol to build up in us is via meat intake.

 Lipids function in membranes, as energy storage, and hormones.

 Enzymes can be affected by the temperature and pH. Most enzymes function wwithin certain temperature levels and pHs and become denatured (term meaning useless or broken) when not used in their optimal range. For example, the hydrocholoric acid (HCL) in our stomach functions best in the very acidic environment of our stomachs.

 Proteins are made by the process of translation. However, for translation to occur, transcription must take place. In transcription, the DNA is read and copied to make mRNA strands. The mRNA then goes to the ribosomes where it is read and complementary tRNA molecules bring in appropriate amino acids that conform to the mRNA. These amino acids are joined to make polypeptide chains.

 In DNA, the purine adenine bonds with the pyrimidine thymine and the purine guanine can bond with the pyrimidine cytosine. In RNA, the pyrimidine uracil takes the place of thymine.

 They are the neutral lipids (have no charge at cellular pH), phospholipids, and steroids.

 As a general rule, any nonpolar substance can dissolve water. This is because lipids are usually not charged and are considered nonpolar. Only nonpolar can dissolve nonpolar. Thus polar substances like water cannot dissolve lipids.

 The best and most healthy way to obtain proteins are from legumes, nuts, and beans.

 Protein structure can be studied in a variety of ways that include X-ray diffraction, and mass spectrophotometry.

 ATP, cAMP, and NADH are all examples of important nucleotides. ATP is very important since it is the primary energy currency of all cells. cAMP regulates some functions and controls some hormones. NADH functions in oxidation and reduction reactions.

 In a typical human haploid cell, there are 3 x 10E9 base pairs.