Tues chem

Introduction to Carbohydrates and Isomers

• Carbohydrates serve as a primary energy source for cells.

• Isomers refer to molecules that have the same chemical formula but different structural arrangements.

• Fructose (C6H12O6) and Glucose (C6H12O6) are isomers:

  • They consist of the same atoms but are arranged differently in structure.

Metabolism and Signaling

• Metabolism involves the conversion of nutrients into energy, with signaling playing a crucial role in how cells respond to various carbohydrates.

• There is ongoing complexity in understanding how different sugars affect metabolism individually and through signaling pathways.

Monosaccharides and their Role

• Monosaccharides are simple sugars and fundamental building blocks of carbohydrates.

• Examples include glucose and fructose, both of which are monosaccharides.

• Deoxyribose and ribose are important sugars related to nucleic acids.

  • Deoxyribose: sugar with an oxygen atom removed from ribose.

  • Nomenclature in biochemistry can be intimidating, but breaking down the words can aid understanding.

Importance of Carbon in Biological Molecules

• Carbon is fundamental in biology due to its ability to form four covalent bonds, allowing for the complex structures required for life.

• Structural formulas often omit carbon symbols to simplify representation, indicating the presence of carbon at every vertex in the structure.

Formation of Disaccharides

• Sucrose is formed by joining glucose and fructose via a dehydration synthesis reaction.

  • This process involves removing a water molecule (hydrolysis) from the monosaccharides, allowing their components to bond.

• Dehydration Synthesis: A common process in creating carbohydrates, proteins, fats, and DNA.

  • Hydrolysis: Breaking down molecules by adding water, necessary for digestion and metabolic processes.

Polysaccharides and Energy Storage

• Polysaccharides are long chains of monosaccharides; common examples are starch, glycogen, and cellulose.

• Starch: energy storage in plants (e.g. potatoes).

• Glycogen: energy storage in animals, synthesized when blood sugar levels are high.

• Cellulose: structural component of plant cell walls; humans cannot digest cellulose.

Lipids and Fats Overview

• Lipids, like triglycerides, are nonpolar and hydrophobic, playing key roles in cell membranes and energy storage.

• Triglycerides consist of glycerol and three fatty acid chains formed by dehydration synthesis.

• Saturated vs. Unsaturated Fats:

  • Saturated fats have no double bonds, making them rigid and solid at room temperature.

  • Unsaturated fats have double bonds resulting in kinks, making them liquid at room temperature (e.g., plant oils).

Phospholipids and Membrane Structure

• Phospholipids: important for cell membranes; created similarly to triglycerides but with a phosphate group replacing one fatty acid.

• Membrane structure forms a bilayer, essential for maintaining cellular integrity and function in an aquatic environment.

Proteins: Formation and Functionality

• Proteins are polymers of amino acids, formed through peptide bonds via dehydration synthesis.

• Folding and shape determine protein functionality; structures are classified primarily, secondarily, and tertiarily.

  • Primary structure: Sequence of amino acids.

  • Secondary structure: Local folding patterns (e.g. alpha helices and beta sheets).

  • Tertiary structure: Overall 3D shape.

  • Quaternary structure: Arrangement of multiple polypeptide chains.

Amino Acids and Genetic Information

• There are 20 amino acids, each with specific properties influenced by their R groups.

• A single amino acid change can lead to significant changes in protein function (e.g., sickle-cell disease).

• Genes encode proteins; mutations can lead to disease.

Nucleic Acids: DNA and RNA

• DNA: serves as the genetic blueprint, composed of nucleotides (adenine, thymine, cytosine, guanine).

  • Deoxyribose sugar gives DNA structural stability.

  • DNA is double-stranded, facilitating accurate replication.

• RNA: single-stranded; includes ribose and bases adenine, uracil, cytosine, and guanine.

  • RNA is less stable than DNA and crucial for protein synthesis.

ATP: The Energy Molecule

• Adenosine Triphosphate (ATP): primary energy carrier in cells.

  • Energy is released when high-energy phosphate bonds are broken (hydrolysis) and used in cellular processes (muscle contraction, active transport).

  • ATP is regenerated through dehydration synthesis from ADP and inorganic phosphate.

Summary

• Understanding isomers, carbohydrates, lipid structures, proteins, and nucleic acids will help in mastering molecular biology concepts.

• Notice how biological molecules are interconnected through various biochemical processes like dehydration synthesis and hydrolysis, which underlie metabolism and cellular function.