1 Chemical Level of Organization Quiz

Chemical Level of Organization

• The chemical level of organization underlies all other levels of biological organization.
• Living organisms are composed of various substances categorized as inorganic and organic compounds.
• Basic building blocks include elements, atoms, and chemical bonds.

Chemical Organization Overview

• Biological process overview:
  • Basics (fundamental concepts)
  • Types of substances
  • Types of chemical bonds
  • Chemical reactions and energy
  • Water
  • Salts, electrolytes, anions, and cations
  • Acids, bases, buffers, pH, O₂ & CO₂
  • Carbohydrates
  • Lipids
  • Proteins and enzymes
  • Nucleotides

Elements and Compounds

• Elements are the fundamental pure substances. These cannot be broken down or created using typical chemical means.
• Compounds are substances made when two or more elements bond
• Atoms are the smallest parts of an element that remain unique to that element.
• Bonds are electrical attractions that hold atoms together. Covalent and hydrogen bonds are particularly significant.

Types of Bonds

• Ionic bonds: Occur between oppositely charged ions. Example: sodium and chloride in salt
• Hydrogen bonds: A hydrogen atom already bonded to an electronegative atom forms a bond with another electronegative atom in another molecule. Example: Hydrogen and oxygen in water molecules; bonds within the same molecule of water
• Covalent bonds: Atoms share electrons for mutual stabilization. Example: hydrogen and oxygen in water molecules; bonds in a single water molecule

The Role of Energy in Chemical Reactions

• Chemical energy is potential energy within chemical bonds. It's released when bonds break and stored when bonds are formed.
• Types of chemical reactions:
  • Synthesis (anabolic): Two or more substances combine to form a more complex substance. Example: A + B + energy —> AB
  • Decomposition (catabolic): A complex substance breaks down to two or more simpler substances. Example: AB —> A + B + energy
  • Exchange: Both decomposition and synthesis occur together, forming two new compounds. Example: AB+CD —> AD+CB

Factors Influencing the Rate of Chemical Reactions

• Properties of the reactants: -Surface area -Physical state (solid, liquid, gas)
• Temperature
• Concentration of reactants
• Pressure
• Enzymes (organic catalysts) lower activation energy, increasing the rate of reaction

Overview of Organic and Inorganic Compounds

• Inorganic compounds:
  • Examples: water, carbon dioxide (CO₂), oxygen (O₂), acids, bases, salts, electrolytes.
• Organic compounds:
  • Examples: carbohydrates, lipids, proteins, ATP, nucleic acids (DNA, RNA)
• Key difference: Organic compounds contain carbon atoms and carbon-to-carbon or carbon-to-hydrogen bonds, along with functional groups attached to a carbon-containing core.

Inorganic Molecules- Water

• Properties of water:
  • Universal solvent
  • Lubricant and cushion
  • High specific heat
  • Crucial in chemical reactions

Fluid Compartments

• Intracellular fluid (ICF):
  • Largest fluid compartment
  • Facilitates intracellular chemical reactions
• Extracellular fluid (ECF):
  • External environment of cells
  • Transports substances to and from cells
• Plasma (part of ECF):
  • Fluid component of blood
• Interstitial fluid (IF) (part of ECF):
  • Surrounds cells not in the blood

Composition of Body Fluids

• Plasma and interstitial fluid (ECF components) have similar chemical compositions, but intracellular fluid (ICF) has distinct differences (mainly ion concentrations, like sodium (Na+), potassium (K+), bicarbonate [HCO3-], chloride (Cl-) & protein anions).
• Concentration differences between ECF and ICF are importantly maintained by the Na+/K+ ATPase pump.

Components of Fluid Compartments

• Solutes: dissolved substances in a solution.
• Solvent: solution that solutes dissolve into.
• Salts: ionic compounds composed of anions and cations.
• Electrolytes: conduct electrical currents in solutions.
• Acids: dissociate into hydrogen (H+) ions and anions.
• Bases: dissociate into hydroxyl (OH−) ions and cations.

The Concept of pH

• pH: a measure of acidity or alkalinity.
• Water with pH 7 is neutral.
• Lower pH values indicate acidity (e.g. blood with pH below 7.35 is acidic)
• Higher pH values indicate alkalinity.

Buffers and their effect on acids and bases

• Buffers: Solutions of weak acid and its conjugate base that help neutralize slight changes in acidity or alkalinity.
• Buffer pairs are critical in plasma and inside cells (ICF) for maintaining blood in a normal pH range.

Inorganic Molecules- O₂ and CO₂

• Oxygen (O₂): essential for complete decomposition reactions, releases energy in the body.
• Carbon dioxide (CO₂): A waste product of cellular respiration. Its presence helps maintain the appropriate acid-base balance.