Foundation Concepts: Matter and Elements

Definitions and Basic Terms

• Matter: Anything that occupies space and has mass.

• Element: A pure substance that cannot be broken down into simpler substances by chemical means.

• Atom: The smallest unit of an element that retains the properties of that element.

Major Elements in the Human Body

Four elements make up approximately 96% of the human body:

• Oxygen (O): 65%

• Carbon (C): 18%

• Hydrogen (H): 10%

• Nitrogen (N): 3%

Element Symbols and Atomic Structure

• Na: Sodium

• K: Potassium

• Ca: Calcium

• Fe: Iron

• Mg: Magnesium

• Atomic Number: Determined by the number of protons in an atom.

Ions and Isotopes

• Ion: An atom or molecule with a net electric charge due to the loss or gain of electrons. Example: Na+ and Cl- form NaCl (sodium chloride).

• Isotope: Atoms of the same element with different numbers of neutrons.

Chemical Bonds

Types of Chemical Bonds

• Hydrogen bonds are responsible for holding DNA strands together and for many properties of water.

Diagram: Hydrogen Bonding in Water

Hydrogen bonds form between the slightly positive hydrogen atom of one water molecule and the slightly negative oxygen atom of another water molecule.

Reaction Types

General Reaction Types and Formulas

• Synthesis:

• Decomposition:

• Exchange:

• Decomposition Example: Protein digestion breaking proteins into amino acids.

• Synthesis Example: Glucose molecules joining to form glycogen.

• Exchange Example: Two different compounds trading components.

Enzymes

Enzyme Function and Mechanism

• Enzyme: A biological catalyst that speeds up chemical reactions by lowering activation energy.

• Activation Energy: The initial energy required to start a reaction.

• How Enzymes Work: Substrate binds to the enzyme's active site, forms a product, then detaches and the process repeats.

• Importance: Enzymes allow the body to perform and repeat processes efficiently without expending excessive energy.

pH and Acid-Base Balance

pH Scale and Blood pH

• pH: A measure of hydrogen ion concentration; lower pH is more acidic, higher pH is more basic.

• Normal pH of Human Blood: 7.4

• Importance: The body cannot function properly outside of the 7.4 pH range; deviations can be fatal.

• Buffer: A system that resists changes in pH. Example: The blood-bicarbonate buffer system.

Macromolecules

Major Classes of Biological Macromolecules

1. Carbohydrates

2. Lipids

3. Proteins

4. Nucleic Acids

Carbohydrates

• Primary Function: Provide energy for cellular processes.

• Monosaccharide: Simple sugar (e.g., glucose).

• Disaccharide: Double sugar (e.g., sucrose).

• Polysaccharide: Complex carbohydrate (e.g., starch).

Lipids

• Shared Property: Largely hydrophobic (repel water).

• Types and Functions:

  • Triglycerides: Long-term energy storage and insulation.

  • Oils: Short-term energy.

  • Phospholipids: Make up cell membranes; regulate what enters and exits the cell.

  • Steroids: Cholesterol (basis for all steroids in the body).

Proteins

• Building Blocks: Amino acids.

• Functions and Examples:

  • Structure: Collagen (skin).

  • Enzymes: Break down starches.

  • Transport: Oxygen (hemoglobin).

• Levels of Protein Structure:

  • Primary: Chain of amino acids.

  • Secondary: Pleated sheets or alpha-helix.

  • Tertiary: Folded structure stabilized by R groups (3D shape).

  • Quaternary: Multiple polypeptide chains (e.g., hemoglobin).

Nucleic Acids

• Types: DNA and RNA.

• Components of a Nucleotide: Phosphate, sugar, and nitrogen base.

• Basic Pathway of Protein Synthesis: DNA → RNA → Protein

ATP and Cellular Energy

ATP Structure and Function

• ATP: Adenosine Triphosphate, the energy currency of the cell.

• Main Components: Adenine (a nitrogenous base), ribose (a sugar), and three phosphate groups.

• Function: Stores and transfers energy for cellular processes by converting glucose into ATP, which can be used by the body. ADP is recycled back into ATP.

Cellular Processes Requiring ATP

• Division of cells

• DNA replication

• Building of proteins

Concept Mapping and Application

• Concept maps help visualize relationships between elements, atoms, bonds, molecules, macromolecules, and cellular function.

Additional Info

• Enzyme specificity is crucial for biological function, as it ensures that enzymes catalyze only specific reactions, preventing unwanted side reactions and maintaining cellular homeostasis.

• Blood pH is tightly regulated by buffer systems, such as the bicarbonate buffer, to prevent harmful shifts in acidity or alkalinity.