University Biology: Chemistry of Water and Biochemistry Notes

Chemistry and Properties of Water

  • Molecular Structure: Inorganic compound featuring 2 covalent bonds and polarity (H2OH_2O) with partial charges (δ+\delta+ on Hydrogen and δ−\delta- on Oxygen).

  • Hydrogen Bonds: Formed due to molecular polarity.

  • Surface Tension: Present at the liquid surface.

  • Universal Solvent: Capable of dissolving diverse molecules (e.g., Na+Na^+, Cl−Cl^-).

  • Chemical Reactivity: Involved in Dehydration synthesis (removing H2OH_2O) and Hydrolysis (adding H2OH_2O).

  • Temperature Regulation: High heat capacity and evaporative cooling properties.

Water Distribution and Body Composition

  • Fluid Comparison: Male bodies are approximately 60%60\% fluid; females are approximately 55%55\% fluid.

  • Compartments: Total body fluid is divided into Intracellular fluid (ICF, ∼2/3\sim 2/3) and Extracellular fluid (ECF, ∼1/3\sim 1/3).

  • ECF Components: Interstitial fluid (∼80%\sim 80\%) and Blood Plasma (∼20%\sim 20\%).

  • Specific Concentrations: Red blood cells (60%60\%), muscle tissue (75%75\%), and blood plasma (92%92\%) are mostly water.

  • Age/Sex Variation: Infants (75−80%75-80\%), Adult men (60−65%60-65\%), Adult women (50−55%50-55\%), and Seniors (as low as 45%45\%).

  • Reference Values: 1 L of H2O=1 kg1\,L\text{ of }H_2O = 1\,kg; 1 lb=0.45 kg1\,lb = 0.45\,kg.

Biochemistry and Carbon

  • Organic Compounds: Contain C-H bonds.

  • Carbon Properties: Forms 4 covalent bonds, is reactive, and is the 4th most abundant element in the universe.

  • Functional Groups: Hydroxyl, Carboxyl, Amine, Phosphate, and Methyl.

Carbohydrates

  • General Formula: (CH2O)n(CH_2O)_n.

  • Monosaccharides: Simple sugars (3-7 carbons) including Glucose, Fructose, Galactose (Hexoses) and Deoxyribose, Ribose (Pentoses).

  • Disaccharides: Two monosaccharides linked via dehydration synthesis: Sucrose (Glucose + Fructose), Maltose (Glucose + Glucose), and Lactose (Glucose + Galactose).

  • Polysaccharides: Polymers like Glycogen (animal storage), Starch (plant storage), and Cellulose (plant structure).

Lipids

  • Characteristics: Insoluble in water (hydrophobic); contain C, H, and little O.

  • Fatty Acids:   - Saturated: Single covalent bonds; solid at room temperature.   - Unsaturated: Contain at least one double covalent bond (kinked); liquid at room temperature.

  • Triglycerides: Major storage form of energy in adipose tissue.

  • Phospholipids: Amphipathic molecules with a polar hydrophilic head and nonpolar hydrophobic tails; major components of plasma membranes.

  • Steroids: Four-ring structure; includes Cholesterol (hormone building block) and sex hormones like Testosterone and Estradiol.

Proteins

  • Composition: C, H, O, N (sometimes S, P); monomers are Amino acids linked by peptide bonds.

  • Structural Organization:   - Primary: Sequence of amino acids.   - Secondary: Twisting and folding.   - Tertiary: 3-D shape/neighboring interactions.   - Quaternary: Aggregation of multiple polypeptides.

  • Protein Denaturation: Loss of function due to altered environments like heat.

  • Functional Groups of Proteins:   - Contractile: Actin and myosin.   - Structural: Collagen and Keratin.   - Catalytic: Enzymes like amylase and lactase.   - Transport: Hemoglobin and ion channels.   - Regulatory: Buffers (Albumin) and hormones (Insulin).   - Defense: Antibodies.   - Chaperones: Heat-shock proteins.

Nucleic Acids and DNA

  • Structure: Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus. Monomers are nucleotides (phosphate, pentose sugar, nitrogenous base).

  • Deoxyribonucleic Acid (DNA):   - Double-stranded helix.   - Sugar: Deoxyribose; Bases: Adenine (A), Guanine (G), Cytosine (C), Thymine (T).   - Historical figures: James Watson, Francis Crick, Rosalind Franklin, Maurice Wilkins.   - Fact: Each cell contains ∼2 m\sim 2\,m of DNA (total human DNA is ∼250\sim 250 round trips to the sun).

  • Genes: Units of inheritance; humans have ∼22,000\sim 22,000 genes.

RNA and Energy Metabolism

  • Ribonucleic Acid (RNA):   - Single-stranded.   - Sugar: Ribose; Bases: Adenine, Uracil, Guanine, Cytosine.   - Types: Messenger RNA (mRNA), Ribosomal RNA (rRNA), Transfer RNA (tRNA).

  • Adenosine Triphosphate (ATP):   - Body's energy currency.   - Stores and transfers energy in high-energy phosphate bonds.   - Catabolism creates ATP; hydrolysis of ATP releases energy for cellular work.

Questions & Discussion

  • Stop and Think Question: Nucleic acids contain all of the following elements except?

  • Response: D. Potassium.