Levels of Protein Structure There are four levels of structure in proteins Three are related to a single polypeptide chain The fourth level relates to a protein that has two or more polypeptide cha...
Amino Acid: Structure Proteins Proteins are polymers (and macromolecules) made of monomers called amino acids The sequence, type and number of the amino acids within a protein determines its shape ...
Nature of the Genetic Code The triplet code The sequence of DNA nucleotide bases found within a gene is determined by a triplet (three-letter) code Each sequence of three bases (i.e. each triplet o...
Translation Translation occurs in the cytoplasm of the cell After leaving the nucleus via a nuclear pore, the mRNA molecule attaches to a ribosome In the cytoplasm there are free molecules of tRNA ...
Transcription A gene is a sequence of nucleotide bases in a DNA molecule that codes for the production of a specific sequence of amino acids, that in turn make up a specific polypeptide (protein) T...
RNA: Structure Like DNA, the nucleic acid RNA (ribonucleic acid) is a polynucleotide – it is made up of many nucleotides linked together in a chain Like DNA, RNA nucleotides contain the nitrogenous...
DNA: Structure The nucleic acid DNA is a polynucleotide – it is made up of many nucleotides bonded together in a long chain DNA nucleotide DNA molecules are made up of two polynucleotide str...
Mononucleotides: Structure Both DNA and RNA are polymers that are made up of many repeating units called nucleotides Each nucleotide is formed from: A pentose sugar (a sugar with 5 carbon atoms) A ...
Osmosis All cells are surrounded by a cell surface membrane which is partially permeable Water can move in and out of cells across the cell surface membrane by a process called osmosis Osmosis is t...
