General Biochemistry - Lecture 1

General Biochemistry - Lecture 1

• The lecture covers general biochemistry concepts, focusing on the levels of organization in living organisms, chemical context of life, syllabus, functional groups, and different types of bonds.
• Living organisms are composed of complex structures, ranging from atoms to complex organisms, with increasing levels of complexity in biological molecules, organelles, cells, tissues, organs, and organ systems.
• About 96% of an organism's weight is composed of carbon (C), oxygen (O), hydrogen (H), and nitrogen (N).
• Other elements like phosphorus (P), sulfur (S), calcium (Ca), and potassium (K) account for the remaining 4% of an organism's weight.

Syllabus

• The syllabus covers introduction to organic biomolecules, including functional groups and stereochemistry.
• Topics also include acid/base properties of amino acids, buffers, titrations and water electrolytes.
• Other topics include chemistry, structure and function of proteins, enzyme kinetics, cofactors, vitamins, chemistry of carbohydrates, glycolysis, gluconeogenesis, glycogen metabolism, regulation of blood sugar, diabetes mellitus, TCA cycle, oxidative phosphorylation and vitamins, chemistry of lipids, fatty acid metabolism, and amino acid metabolism.

Functional Groups

• Important functional groups in biochemistry include hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, and phosphate groups.

Hydroxyl Group

• Alcohols contain hydroxyl groups (-OH).
• Hydroxyl groups are polar, making them attract water molecules and contributing to dissolving organic compounds.

Carbonyl Group

• Carbonyl groups (C=O) are polar.
• Aldehydes (-CHO) occur at the end of the carbon skeleton, while ketones are located in the middle of the skeleton.
• Ketones and aldehydes are present in sugars.

Carboxyl Group

• Carboxylic acids, or organic acids, contain carboxyl groups (-COOH).
• Carboxyl groups acts an acid; able to donate a proton (H+).

Amino Group

• Amines are functional groups containing amino groups (-NH2).
• Amino groups acts as a base and can accept protons from surrounding solutions.

Sulfhydryl Group

• Thiol groups contain sulfhydryl groups (-SH).
• Two sulfhydryl groups react, forming a covalent bond, which helps stabilize protein structure.

Phosphate Group

• Organic phosphates contain phosphate groups (-PO4 2-).
• The phosphate group contributes a negative charge to the molecule and allows molecules that contain the phosphate group, like ATP, to react with water to release energy.

Macromolecules

• The four major classes of macromolecules in cells are proteins, lipids, nucleic acids (DNA/RNA) and carbohydrates.

Electrostatic Forces

• Electrostatic interactions occur between cations (+ charge) and anions (- charge).
• Like charges repel, while unlike charges attract, and are important in protein folding, RNA folding, and DNA helix.
• Electrostatic interactions depend on salt concentration and pH.

Water Molecules

• Water molecules are polar.
• Water's polarity allows it to form hydrogen bonds with itself and dissolve hydrophilic (ionic or polar) substances.

Hydrogen Bonds

• Hydrogen bonds are relatively weak electrostatic forces or interactions between hydrogen atoms and nitrogen, oxygen, or fluorine atoms.
• Hydrogen bonds are important in biological molecules like water, alcohols, and amines.

Ionic Bonds

• Ionic bonds are electrostatic interactions between two oppositely charged ions.
• Biological molecules have interactions between different charged groups.

van der Waals Interactions

• van der Waals interactions occur between nonpolar molecules.
• These forces are weak but significant in biological molecules.

Covalent Bonds

• Covalent bonds form when atoms share pairs of electrons.
• Covalent bonds are important structures in biological molecules for stability.

Hydrophobic Interactions

• Hydrophobic substances that lack polar groups are insoluble in water.
• Nonpolar molecules aggregate in water to minimize their contact with water molecules, leading to energetically favorable hydrophobic interactions.

Stereochemistry

• Isomers have the same molecular formula but different structures and properties.
• Cis-trans isomers have different spatial arrangements around double bonds.
• Enantiomers are mirror images of each other.