bio seminar 3

Key Concepts of Biological Processes

Fundamental Properties of Universe

• The concept of diffusion and concentration gradients is prevalent in biology.

• Diffusion: Movement of molecules from an area of high concentration to an area of low concentration until equilibrium is reached.

• This property is crucial for understanding various biological phenomena.

Molecular Movement and Temperature

• Increasing temperature adds kinetic energy to molecules, causing them to move more randomly.

• Example: Two magnets will stick together due to attractive forces, but can be separated with enough energy (force).

• Intermolecular Forces Disrupted: High temperature affects all intermolecular forces:

  • Hydrogen Bonds: Essential in protein secondary structures.

  • Temperature increase can denature proteins (alter their structure).

• Frying Eggs: Illustration of denaturation - the process of changing the physical structure of proteins, such as the transition from colorless to white.

• Denaturation does not affect all proteins at once; it occurs progressively.

pH Changes and Protein Structure

• pH influences the ionic interactions holding proteins together.

• Lower pH (increased H+ concentration) impacts ionic bonds, particularly:

  • Carboxyl Groups: Found in amino acids like aspartic acid and glutamic acid. They can lose protons, affecting their charge.

  • Basic amino acids (lysine, arginine, histidine) can accept protons, changing from neutral to positively charged in acidic conditions.

• Ionic Bonds Disrupted: Change in charges results in disruption of ionic interactions.

• Le Chatelier's Principle: encourages the system to maintain equilibrium through shifts in proton availability.

Impact of Polar and Nonpolar Molecules

• High Concentration of Polar Molecules: Introduction of polar solvents can disrupt protein interactions and force R groups to interact differently (e.g., methanol).

• High Concentration of Nonpolar Molecules: Alters interactions at the tertiary level, impacting nonpolar R groups.

  • Example: Benzene and similar compounds disrupt London dispersion forces.

  • Denaturation may occur, affecting protein functionality and structure.

Application in Laboratory Research

• Use of denaturation in proteomics: process to simplify and isolate proteins for study.

• Chemicals like hydrofluoric acid and urea used to disrupt molecular forces and analyze proteins.

• Electrophoresis and Chromatography: Techniques to separate denatured proteins for further analysis and sequencing.

Summary of Amino Acids Affected by pH

• Carboxyl Group (COOH): Loses protons in low pH, affecting binding and charge.

• Amino Group (NH2): Accepts protons in acidic solutions, leading to a positive charge.

• Focus on understanding how charge shifts affect protein structure through examples of specific amino acids.

Historical Context of Cellular Evolution

• Prokaryotic cells: Simple, single-celled organisms without a nucleus; ancestor to complex eukaryotic cells.

• Timeline of Evolution: From prokaryotes (1.5 billion years) to eukaryotes (2.1 billion years) and the Cambrian explosion (600 million years).

• Key Eukaryotic Developments: Formation of organelles through processes like invagination and endosymbiosis.

Photosynthesis and Oxygen Production

• Photosynthesis: Building glucose from light energy; produces oxygen, vital for aerobic life.

• Oxygen's role and how it cycles through ecosystems; diffusion from water to atmosphere.

• Impact of oxygen in forming ozone layer and its protective functions against UV radiation.

Prokaryotic vs. Eukaryotic Cells

• Shared characteristics: Common genetic code implies shared ancestry.

• Differences: Eukaryotes contain membrane-bound organelles, unlike prokaryotes.

• Size and complexity: Prokaryotic cells are smaller and simpler in structure than eukaryotic cells.