Fluid Mosaic Structure Cells are enclosed by a double-layered fluid membrane consisting of a mosaic of components which include proteins, glycoproteins, glycolipids, phospholipids, saturated and unsaturated fatty acids, and cholesterol. The phospholipid heads are polar, allowing them to orient themselves towards the watery cytoplasm and extracellular space. The hydrophobic tails orient towards each other. Proteins […]
An important concept that you will encounter in biochemistry is the hydrophobic and hydrophilic nature of different compounds. A compound is hydrophobic if it cannot dissolve in water, and hydrophilic if it can dissolve in water. You may already know from experience that fats and oils are hydrophobic, which makes them float on top of […]
Proteins can be separated based on their isoelectric point and molecular weight using electrophoresis. This allows us to observe and compare structural and functional differences in proteins, and enables further analysis of specific proteins we may want to study. Separation by Isoelectric Point Separation by isoelectric point is called isoelectric focusing. In this technique, samples […]
Regulation of energy metabolism can occur at the gene level, where enzymes needed for energy metabolic pathways are either transcribed, or their transcription inhibited. A well-studied example is the Lac Operon which can be seen in E. coli bacteria. The Lac Operon is characterized by an operator which is essentially an on/off switch that controls […]
Three sequences of nucleotides called a codon on the mRNA code for amino acids. There are 64 codons. Sixty-one of them code for amino acids including AUG which is a start codon corresponding to methionine. Three codons are referred to as STOP codons. Stop codons terminate translation of mRNA. The stop codons are UGA, UAA, […]
The DNA contains the code for making all proteins. In order for proteins to be synthesized, the code on the DNA for making the protein of interest must be transcribed. Imagine trying to make a cake (the protein) that you have never made before. Consider that the book with the recipe is in a rare […]
