Copy of Unit 1_ Chemistry of Life Full Notes Set

Unit 1: Chemistry of Life

Table of Contents

  • 1.1 Structure of Water and Hydrogen Bonding

  • 1.2 Elements of Life

  • 1.3 Introduction to Biological Macromolecules

  • 1.4-1.7 Properties of Biological Macromolecules (Carbohydrates, Lipids, Proteins, Nucleic Acids)

Topic 1.1: Structure of Water and Hydrogen Bonding

Enduring Understanding: SYI-1

  • Living systems are organized in a hierarchy of structural levels that interact.

Learning Objectives

Essential Knowledge: SYI-1.A

  • SYI-1.A.1: Explain how the properties of water resulting from its polarity and hydrogen bonding affect its biological function.

  • SYI-1.A.2: Living systems depend on properties of water due to its polarity and hydrogen bonding.

  • SYI-1.A.3: Hydrogen bonds between water molecules result in cohesion, adhesion, and surface tension.

Water Structure & Hydrogen Bonding

  • Cellular chemistry and metabolism predominantly occur in the cytosol, a water-based solution.

  • Properties of Water:

    • Common in organism bodies.

    • Unique chemical properties vital for life.

Covalent Bonds in Water

  • Covalent Bonds: Involve sharing of electrons between hydrogen and oxygen atoms within a water molecule.

  • Questions:

  • Which atom has more electrons? (Oxygen)

  • What is the charge of an electron? (Negative)

Polar & Nonpolar Covalent Bonds

  • Covalent Bond: Involves sharing of electrons.

    • Nonpolar covalent: Electrons shared equally.

    • Polar covalent: Electrons not shared equally, creating partial charges.

Water as a Polar Molecule

  • Polar molecules have an uneven distribution of electrons, leading to positive and negative poles that affect molecular interactions.

Interaction of Water Molecules

  • Water molecules can attract and bond together due to their polarity, leading to unique physical properties.

Hydrogen Bonds

  • Hydrogen bonds hold multiple water molecules together.

  • Polar covalent bonds hold single water molecules, while hydrogen bonds hold many together, demonstrating cohesion.

Properties of Water

Cohesion

  • Water's tendency to stick to itself due to hydrogen bonding.

Adhesion

  • Water's ability to stick to other surfaces, facilitating interactions with diverse environments.

Surface Tension

  • Result of hydrogen bonding, causing the water surface to exhibit tension, allowing some objects to rest on it without sinking.

Ice Density & Specific Heat

  • Ice is less dense than water because hydrogen bonds maintain a fixed distance between molecules.

  • Water has high specific heat, requiring more energy to change temperature compared to other substances.

Topic 1.2: Elements of Life

Enduring Understanding: ENE-1

  • Living systems require energy input and exchange of macromolecules.

Essential Knowledge: ENE-1.A

Composition of Macromolecules

  • Organisms exchange matter to grow and maintain structure.

    • Key elements: Carbon, Nitrogen, Phosphorus.

  • CHONPS Elements:

    • C: Carbon

    • H: Hydrogen

    • O: Oxygen

    • N: Nitrogen

    • P: Phosphorus

    • S: Sulfur

The Central Role of Carbon in Biomolecules

  • Carbon is present in all biomolecules and forms four covalent bonds, facilitating complex biological molecules.

  • Different biomolecules include:

  • Carbohydrates: CHO

  • Lipids: CHO

  • Proteins: CHON

  • Nucleic Acids: CHONP

Nitrogen & Phosphorus Uses

  • Nitrogen: Builds proteins & nucleic acids.

  • Phosphorus: Builds nucleic acids & some lipids.

Carbohydrate Structure

  • Glucose Formula: C6H12O6, demonstrating the hydrated nature of carbohydrates, exhibiting a 1:2:1 ratio of elements.

Topic 1.3: Introduction to Biological Macromolecules

Enduring Understanding: SYI-1

  • Systems have levels that interact meaningfully.

Learning Objectives

Essential Knowledge: SYI-1.B

  • Hydrolysis and dehydration synthesis are key processes for forming and breaking covalent bonds in macromolecules.

Carbohydrate Structure

Simple vs. Complex Carbohydrates

  • Simple carbohydrates (monosaccharides) bond to form complex carbohydrates (disaccharides) through dehydration synthesis.

Building Macromolecules: Synthesis Types

  • Dehydration Synthesis: Forms covalent bonds while releasing water (H2O).

  • Hydrolysis: Breaks covalent bonds by utilizing water.

Carbohydrate Function

  • Carbohydrates serve as energy storage and structural materials.

  • The arrangement of elements determines function: starch (storage) vs. cellulose (structure).

Lipid Structure & Function

  • Lipids share a similar chemical makeup (C, H, O) with carbohydrates but vary in ratios:

    • Carbohydrates have a 1:2:1 ratio.

    • Lipids have less oxygen and often consist of long hydrocarbon chains.

  • Saturated vs. Unsaturated Fats:

    • Saturated (solid at room temp, animal fats).

    • Unsaturated (liquid at room temp, plant fats - due to double bonds that create kinks).

Structure of Lipids

  • Phospholipids: Contain polar heads and nonpolar tails, forming bilayers in cellular membranes which are flexible and fluid.

Proteins: Composition and Structure

  • Made of amino acids, containing amino and carboxyl groups.

  • Each amino acid has a unique R-group dictating its properties (polar, non-polar, charged).

  • Building Proteins: Amino acids link via peptide bonds in dehydration synthesis reactions.

Levels of Protein Structure

  1. Primary: Linear amino acid sequence.

  2. Secondary: Local folding into helices or sheets (e.g. alpha-helix, beta-pleated).

  3. Tertiary: 3D structure due to R-group interactions.

  4. Quaternary: Complex of multiple polypeptide chains.

Nucleic Acids

  • Monomer: Nucleotide (contains phosphate group, 5-carbon sugar, and nitrogenous base).

  • Differences between DNA and RNA:

    • DNA is double-stranded; RNA is single-stranded.

    • DNA contains thymine; RNA contains uracil.

Nucleic Acid Assembly

  • Created through bonds between sugar and phosphate, forming a sugar-phosphate backbone.

  • Directionality established through 5’ and 3’ ends, with antiparallel strands in DNA.

End of Notes

Tips for Mastery

  • Annotate notes in own words.

  • Make connections between topics.

  • Ask questions to clarify doubts.

  • Utilize supporting videos for understanding.