Biomolecule Structure, Drug Design, and Cellular Processes
Biomolecule Structure Determination
Several methods exist for determining the structure of biomolecules. Here are two prominent examples:
X-Ray Crystallography
X-ray crystallography is a high-resolution technique analogous to microscopy. It allows visualization of protein structures at the atomic level, enhancing our understanding of protein function. We can study protein interactions with other molecules, conformational changes, and catalysis (in enzymes). This knowledge aids in designing novel
Read MorePlasmid DNA Purification in Bacteria
Lab #4: Purification of Plasmid DNA
Introduction
Plasmids are circular DNA molecules that constitute accessory genetic material and replicate independently of the host cell chromosome. They are naturally found in bacteria, with sizes ranging from approximately 5,000 to 400,000 base pairs (bp).
The information plasmids contain may confer upon their host cell traits such as antibiotic resistance, the capacity for degradation of aromatic compounds, or the fermentation of sugars, among others. The number
Read MoreEnzymes: Biological Catalysts and Their Mechanisms
Enzymes: Biological Catalysts
Enzymes are biological catalysts (proteins). They do not disturb the balance of the reaction. Enzymes contain an active site within the globular protein structure. They are highly specific. Specificity is determined by the complementarity between the active site and the substrate. They possess great catalytic power (106 or more) and are not permanently altered by the reaction.
The enzyme provides necessary proximity and orientation for the reaction to occur. There is
Read MoreEnzyme Structure, Classification, and Regulation
Enzyme Structure and Function
Enzyme activity depends on the integrity of its structure. Maintaining primary, secondary, tertiary, and quaternary structures ensures that the enzyme retains its functionality.
Cofactors and Coenzymes
Some enzymes require the participation of other chemicals:
- When one or more metal ions, such as iron, magnesium, or zinc, are involved, they are designated as cofactors.
- If the chemical components are more complex organic molecules, they are called coenzymes.
- When the coenzyme
Immunology Key Concepts: Pathways, Organs, and Selection
1. Cytosolic vs. Endocytic Antigen Processing
| Characteristic | Cytosolic Pathway | Endocytic Pathway |
|---|---|---|
| Antigen origin | Intracellular (viruses, cytosolic proteins) | Extracellular (bacteria, ingested pathogens) |
| MHC involved | Class I | Class II |
| Activated cell type | CD8+ (cytotoxic T cells) | CD4+ (helper T cells) |
| Antigen processing | In the proteasome | In endosomes and lysosomes |
| Peptide transport | TAP (Transporter associated with processing) | From endosomes to MHC molecules in vesicles |
| Polymorphic zones | α1 and α2 | α1 and β1 |
2. Primary
Read MoreBacterial Genetics: Competency, Plasmids, PCR, and Electrophoresis
Bacterial Genetics
Explain Competency
- The physical state of a bacterial cell which allows nucleotide bases in primers to anneal to the complementary base present in a DNA template.
Describe the Transformation Experiment
- The uptake of free-floating DNA from the environment by bacterial cells.
Characteristics of a Plasmid: pGLO Example
- Plasmids carry full-length genes and, therefore, can introduce new genotypes into bacterial cells, which can cause new phenotypes.
Function of Buffers in Plasmid DNA Isolation
- An