Genetic Code and Mutations

• Dilution factor relates to the concentration change of a substance in a solution.
• Coomassie blue dye binds to the peptide backbone, a common part of proteins.
• Enzymes catalyze biochemical reactions.
• The active site is a pocket or groove on an enzyme's surface where substrates bind.
• Enzyme activity is affected by both temperature and pH levels.

Central Dogma of Molecular Biology

• The flow of genetic information in cells proceeds from DNA to mRNA to protein.
• Genes determine the sequence of mRNA molecules.
• mRNA sequences dictate the amino acid sequence during protein synthesis.

Gene Mutations

• A gene mutation involves a change in the nucleotide sequence of a gene.
• Mutations might involve a single nucleotide.
• Mutations can arise from copying errors, chemicals, or viruses.

Types of Gene Mutations

• Point Mutations
• Silent
• Missense
• Nonsense
• Frameshift Mutations
• Insertions
• Deletions

Point Mutation

• Point mutation involves the change of a single nucleotide.
• It can include the deletion, insertion, or substitution of one nucleotide.
• Sickle cell disease results from a single nucleotide substitution in the hemoglobin gene.

Frameshift Mutation

• Frameshift mutation arises from inserting or deleting one or more nucleotides.
• It alters the reading frame, leading to incorrectly built proteins.

Phylogenetic Tree

• Phylogenetic tree is a diagram illustrating the evolutionary relationships among organisms.
• Branching patterns reflect how species evolved from common ancestors.
• Closely related species share a more recent common ancestor.

Genetics

• Polymerase Chain Reaction (PCR) is the most common DNA test.
• Autosomes are chromosomes that are not sex chromosomes.
• One chromosome of each pair comes from each parent.
• Each pair of chromosomes is referred to as a homologous pair.
• Homologous chromosomes have the same size, shape, gene organization.
• Homologous chromosomes contain the same genes in the same loci, but versions of the genes may be different.
• The coding region encodes for the physical traits.
• 98-99% of human DNA is considered non-coding.
• Short-tandem repeats (STRs) are unique repeating patterns in non-coding DNA and can differentiate individuals
• STRs are present at specific locations (loci) on everyone’s chromosomes.
• A DNA profile at one STR site is shared by 5-20% of people.

PCR Components

• DNA template provides the sequence to be amplified.
• Primers are short DNA pieces specific to the sense or antisense strands, binding via hydrogen bonds.
• DNA polymerase is the enzyme that synthesizes new DNA strands.
• Taq polymerase is a thermostable enzyme from Thermus aquaticus, tolerating temperatures above 90°C.
• Deoxyribose nucleoside triphosphates (dNTPs) are the building blocks for the new DNA strands.
• A reaction buffer maintains pH and contains ions like manganese, magnesium, and potassium.
• PCR grade water is used as a solvent and is free of ions that can inhibit the reaction.

PCR Process

• Denaturation involves breaking hydrogen bonds between complementary base pairs, resulting in single-stranded DNA.
• Annealing involves short primer pieces binding via hydrogen bonds.
• Elongation uses polymerase to add free dNTPs to the primer ends in the 5’ to 3’ direction.
• Primers will bind to single stranded DNA formed via previous extension in the next cycle
• The amplicon ultimately forms when the polymerase extends from the forward primer on a strand that was generated by amplification from the reverse primer or vice versa.
• The amount of amplicon increases exponentially (2n-1) in subsequent cycles.

Gel Electrophoresis

• Gel electrophoresis separates DNA based on size/length, charge, and mass.
• DNA is negatively charged.