Study Notes on Biochemistry and Cell Biology Concepts

BCH 231: Cell Biology, pH, and Buffer

What is Biochemistry?

  • Biochemistry is a branch of science that studies the structures, functions, and organization of living things using molecular terms.
  • Key Questions in Biochemistry:
    • 1. What are the chemical structures of the components of living things?
    • Explanation of the structure-function relationship: The structure of any biological component determines its function.
    • 2. How do these components interact to give rise to organized supramolecular structures (cells, multicellular tissues, and organisms)?
    • 3. How does an organism store and transmit information necessary for growth and reproduction?
    • How does living matter extract energy from its surroundings to remain alive?

States of Metabolism

  • Three metabolic states discussed:
    1. Fasting state
    2. Starvation state
  • Example: When you eat, the body converts glucose and stores it as glycogen.

Chemical Changes in Organisms

  • Discussion on the chemical changes accompanying reproduction and death of cells and organisms.
  • Aging: Role of proteins is significant in cell death.
  • Autophagy: A cellular process where a cell digests and recycles its own damaged components.

Roots of Biochemistry

  • Biochemistry originates from early 19th-century studies.
  • Friedrich Wöhler (1828): Synthesized urea from ammonium cyanate, challenging the vitalism theory.
  • Eduard Buchner & Hans Buchner: Showed that extracts from broken and dead yeast could carry out fermentation, leading to in vitro reactions.
  • James V. Sumner (1926): Crystallized urease from jack bean, demonstrating that enzymes could be simplified in structure.

Discoveries in Cell Biology

  • 17th Century: Robert Hooke discovers the cell.
  • 1895: Walter Flemming discovers chromosomes classified as genetic elements.
  • 1902: Concept of the gene proposed by Gregor Mendel during studies on pea plants. Genes are responsible for the action of chromosomes.
  • 1963: Watson and Crick describe DNA's double helical structure.

Branches of Biochemistry

  • Biochemistry is divided into three principal areas:
    1. Structural Biochemistry: Focuses on the chemical structures of biological components and the relationship of biological functions to chemical structures.
    2. Metabolism: The totality of chemical reactions that occur in living matter.
    3. Genetics Biochemistry: Studies processes and substances that store and transmit biological information.
  • Interdisciplinary Links: Biochemistry interacts with various fields such as:
    • Medical science
    • Physical chemistry
    • Organic chemistry
    • Microbiology
    • Physiology
    • Genetics
  • All diseases exhibit biochemical relationships.

Importance of Chemical Elements in Living Matter

  • Living matter is primarily composed of certain essential elements:
    • Carbon (C)
    • Hydrogen (H)
    • Oxygen (O)
    • Nitrogen (N)
    • Sulfur (S)
    • Phosphorus (P)
  • These elements are crucial due to their tendency to form covalent bonds. For example:
    • The stability of C-C bonds.
    • The potential to form single, double, and triple bonds offers versatility in chemical formation.

Biological Molecules

  • Macromolecules: Also known as polymers, they are large molecules created by combining smaller units or monomers through condensation reactions.
    • Homopolymers: Composed from identical monomer units.
    • Heteropolymers: Composed from different types of monomer units (e.g., proteins).
  • Functions of Biopolymers:
    • Serve as structural components (e.g., cellulose) and energy reserves.

Types of Biological Macromolecules

  1. Nucleic Acids: Involved in formation, storage, transmission, and expression of genetic information.
    • DNA: Acts as a repository for genetic information.
    • RNA: Involved in interpreting and utilizing that genetic information.
  2. Proteins: Have various roles including:
    • Structural roles (e.g., keratin).
    • Transport roles (e.g., hemoglobin, albumin).
  3. Carrying information through hormones and cell surface receptors which release signals.

Notes on Reactions

  • Condensation Reaction: The process opposite to digestion, where molecules join to form larger compounds.
  • Hydrolytic Enzymes: Enzymes involved in digestion of macromolecules.
  • Example of bond formation:
    • For carbohydrates: Glycosidic bonds hold molecules together.
Example Structures

  • General structure for a peptide bond can be represented as:
    (R−N−C−CO−R−H)(R - N - C - CO - R - H)

  • Where R represents different side chains on the amino acid.

  • Glycosidic bond representation:
    (R<em>1−O−C−R</em>2)(R<em>1 - O - C - R</em>2)

  • Showing connectivity where R's can represent atoms or groups in a carbohydrate structure.