Recording-2024-12-13T15:27:01.638Z

Peptide Bonds and Reactions

• Peptide bonds are the type of bond that holds amino acids together.

• Formed through anabolic reactions, which build larger molecules from smaller units.

mRNA Processing

• After base pairing of the gene segment, mRNA undergoes processing.

  • Introns: Non-coding sections of the gene that are removed during mRNA processing.

  • Exons: Coding sequences that are retained and exit the nucleus to be translated into proteins.

• mRNA is modified by adding:

  • 5' G-cap: A modification on the 5' end that helps stabilize the mRNA and aids in the initiation of translation.

  • Poly-A tail: A series of adenine bases added to the 3' end that protects the mRNA from degradation during transport to the ribosome.

Major Biological Molecules

• Four major biological molecules:

  1. Carbohydrates

  2. Lipids

  3. Proteins

  4. Nucleic acids

• Carbohydrates have a general formula of C(H2O)n, indicating twice as many hydrogen atoms as oxygen atoms.

• Lipids: Generally consist of long hydrocarbon chains, often containing fewer oxygen atoms than carbohydrates.

Triglycerides

• Made up of one glycerol molecule and three fatty acid chains (tri- meaning three).

• Phospholipids: Similar structure but contain a phosphate group, important for cell membrane integrity.

Glycogen and Cellulose

• Glycogen: A storage polysaccharide in animals, made of alpha-glucose, featuring a highly branched structure for rapid release of glucose.

• Cellulose: A structural polysaccharide in plants, made of beta-glucose forming long, unbranched chains.

Cells and Their Structures

• Rough Endoplasmic Reticulum (Rough ER): Involved in protein synthesis and export; studded with ribosomes.

• Key characteristics of life:

  • Reproduction

  • Maintain homeostasis

  • Excretion

  • Digestion

  • Metabolism

• Comparison of Prokaryotic and Eukaryotic Cells:

  • Prokaryotes: Circular DNA, single chromosome, no histones.

  • Eukaryotes: Linear DNA, multiple chromosomes, associated with histone proteins.

Cellular Respiration and Photosynthesis

• Cellular Respiration: Process of breaking down glucose to extract energy, involving the Krebs cycle.

• Photosynthesis: Involves carbon fixation in the Calvin cycle to convert carbon dioxide into glucose using light energy.

Transport Mechanisms

• Osmosis: Movement of water across membranes, often high concentration to low concentration gradient.

Genetic Disorders and Inheritance Patterns

• Example: Sickle Cell Anemia, a genetic disorder with complex inheritance patterns.

• Discusses the implications of mutation, selection pressure, and gene flow in small populations.