Recording-2025-03-05T22_50_48.474Z

Amino Acids and Protein Structure

• Amino Acids Introduction:

  • Composed of an amine group, a carboxyl group, a hydrogen atom, and an R group.

  • R Group variability leads to different amino acids, affecting their function and interactions.

Peptide Bonds

• Peptide Bonds:

  • Amino acids are linked together by peptide bonds to form proteins.

  • Proteins are polymers made up of amino acids.

• Linkage Process:

  • The carboxyl group of one amino acid bonds with the amine group of another amino acid.

Conformation of Proteins

• Protein Structures:

  • Proteins can have various conformations, including primary, secondary, tertiary, and quaternary structures.

  • The conformation affects protein function and how it interacts with other molecules.

• Example: Hemoglobin

  • Hemoglobin is a quaternary protein made of multiple heme groups and carries oxygen in the blood.

Denaturation

• Definition:

  • Denaturation is the process where protein structure unravels, typically due to heat, pH changes, or damage from chemicals.

• Cooking Example:

  • When an egg is cooked, the albumin protein changes structure and becomes opaque.

• Heat Shock Proteins:

  • Some proteins retain their structure under heat, known as heat shock proteins.

Nucleic Acids

• Types:

  • DNA (Deoxyribonucleic Acid): Contains genetic information and is located in the cell nucleus.

  • RNA (Ribonucleic Acid): Acts as a messenger and is derived from DNA.

• Nucleotide Structure:

  • Composed of a five-carbon sugar, a nitrogenous base, and phosphate groups.

Bonding in DNA

• Hydrogen Bonds:

  • Form between nitrogenous bases of nucleotides, contributing to the structure of the DNA double helix.

Cell Theory and Structure

• Definition of a Cell:

  • The smallest unit of life and the functional unit of all organisms.

• Cell Origin:

  • Cells come from pre-existing cells, disproving the spontaneous generation theory.

Cell Membranes

• Plasma Membrane:

  • Also known as the lipid bilayer, it regulates entry and exit of substances in a cell.

  • Contains receptors for hormones and proteins for transporting molecules.

Cytoplasm and Organelles

• Cytoplasm:

  • A gel-like substance where most cellular metabolism occurs, containing glucose, ions, and organelles.

• Organelles:

  • Specialized structures with specific metabolic functions, e.g., mitochondria for energy production.

Prokaryotic vs. Eukaryotic Cells

• Prokaryotic Cells:

  • Bacteria and archaea, characterized by lacking a true nucleus.

• Eukaryotic Cells:

  • Organisms with cells that contain a true nucleus.

Cell Size Limitations

• Surface to Volume Ratio:

  • Essential for cell function; a larger surface area enhances nutrient absorption and waste expulsion.

Microscopy and Cell Observation

• Anton von Leeuwenhoek:

  • Established microscopy and was the first to observe cells.

Fluid Mosaic Model

• Description:

  • Describes the cellular membrane's structure where components float freely in the lipid bilayer, allowing flexibility and functionality.

Bacterial and Viral Interaction

• Pathogenesis:

  • Bacteria can cause infections and diseases, with some producing toxins or having mechanisms to evade host defenses.

• Antibiotics:

  • Certain antibiotics target bacterial cell walls or protein synthesis, effectively inhibiting bacterial growth.