Biomolecules in Reductionist Biology Chapter 9

Reductionist Biology

• A physico-chemical approach used to study and understand living organisms through concepts and techniques from physics and chemistry.
• Biomolecules are briefly described in Chapter 9 of the referenced unit.

G.N. Ramachandran

• Founder of the 'Madras school' of conformational analysis of biopolymers.
• Known for discovering the triple helical structure of collagen in 1954; published findings in Nature.
• Developed the 'Ramachandran plot' for analyzing allowed protein conformations.
• Born on October 8, 1922, near Cochin, India; significant early influence from his father, a mathematics professor.
• Graduated top of his class in B.Sc. (Honors) Physics from the University of Madras in 1942.
• Earned a Ph.D. from Cambridge University in 1949; influenced by Linus Pauling's work on protein structures.
• Passed away on April 7, 2001, at the age of 78.

Cytoplasm and Cell Structure

• Cytoplasm is a semi-fluid matrix occupying cell volume in prokaryotic and eukaryotic cells, serving as the main site for cellular activities.
• Eukaryotic cells contain organelles (e.g., endoplasmic reticulum, Golgi complex, lysosomes, mitochondria) which are not found in prokaryotic cells.
• Ribosomes, non-membrane bound organelles, are present in all cells, located in the cytoplasm, chloroplasts (plants), mitochondria, and rough ER.
• Animal cells additionally possess centrosomes, which assist in cell division.

Plasma Membrane Dynamics

• The fluid nature of the plasma membrane enables protein movement, crucial for functions like growth, secretion, and cell division.
• Plasma membranes are selectively permeable, allowing some molecules to traverse without energy (passive transport).
• Neutral solutes and water pass through the membrane via simple diffusion and osmosis, respectively.
• Polar molecules require carrier proteins for transport across the lipid bilayer.
• Active transport involves moving ions or molecules against their concentration gradient using ATP, like the Na+/K+ pump.

Cell Wall and Locomotion Structures

• The cell wall provides a rigid outer covering for plant and fungal cells, offering shape, protection, and facilitating cell-to-cell interactions.
• Cilia and flagella enable cell movement; cilia are short and oar-like, flagella are long and whip-like.
• Prokaryotic and eukaryotic flagella differ structurally, both covered by plasma membrane with an axoneme structure (9+2 arrangement of microtubules).

Centrosome and Centrioles

• The centrosome contains two centrioles arranged perpendicularly, each made up of nine peripheral triplets of tubulin.
• Centrioles are involved in forming the basal body of cilia/flagella and spindle fibers during cell division.

Nucleus Structure

• Robert Brown first described the nucleus in 1831; chromatin (nuclear material) was later identified by Flemming.
• Interphase nucleus features nucleoprotein fibers (chromatin), nucleoplasm, and nucleoli.
• The nuclear envelope comprises two membranes, creating a perinuclear space (10 to 50 nm) that separates nuclear content from cytoplasm, and is continuous with the endoplasmic reticulum.

Explore the concepts of Reductionist Biology through Chapter 9, focusing on the physico-chemical principles applied to understand living organisms. Gain insights into biomolecules and the contributions of G.N. Ramachandran in protein structure. This quiz will enhance your grasp of how physics and chemistry intersect with biology.