Chemistry of Life-2

Chemistry of Life: Anatomy and Physiology

Chapter Overview

  • The chapter focuses on various fundamental concepts of chemistry as they relate to the biological functions in humans.

  • Objectives for students:

    • Illustrate the parts of an atom.

    • Describe the elements and their relative amounts found in humans.

    • Differentiate among atoms, ions, and isotopes.

    • Compare organic vs. inorganic molecules.

    • Describe three important inorganic molecules found in humans.

    • Explain the differences between acids and bases and how they relate to the human body.

    • Draw major functional groups.

    • Explain form and functions for carbohydrates, lipids, proteins, and nucleic acids.

    • Analyze an enzymatic reaction and define the participants.

Nutritional Information

  • Example Study: Doritos Nacho Cheese

    • Serving Size: 1 package

    • Nutrition Values:

    • Calories: 150

    • Calories from Fat: 70

    • Total Fat: 8g (12% DV)

    • Saturated Fat: 1.5g (7% DV)

    • Protein: 2g

    • Carbohydrates: 17g (6% DV)

    • Ingredients listed include whole corn, vegetable oils, cheddar cheese, etc.

Atomic Structure

  • Matter: Anything that has mass and occupies space. States include solids, liquids, and gases.

  • Atom: The smallest unit of matter.

    • Components of an Atom:

    • Protons: Positively charged particles in the nucleus; mass = 1 amu.

    • Neutrons: Neutral particles in the nucleus; mass = 1 amu.

    • Electrons: Negatively charged particles orbits the nucleus; negligible mass.

Electrons and Chemical Bonding

  • Valence Electrons: Electrons in the outermost shell that determine chemical bonding properties.

  • Electron Configuration: Limits exist on the number of electrons per orbital.

    • Octet Rule: Atoms are most stable when their outer electron shell is full:

    • First orbital: Holds a maximum of 2 electrons.

    • Second orbital: Holds a maximum of 8 electrons.

    • Third orbital: Holds a maximum of 8 electrons.

Elements in the Human Body

  • Elements in Biology:

    • 24 elements serve biological roles; 6 elements account for 98.5% of body weight: Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), Phosphorus (P), Calcium (Ca).

  • Minerals: Inorganic elements from soil vital for bodily functions (4% body weight) including calcium, phosphorus, magnesium, and sodium.

Ions and Electrolytes

  • Ions: Charged particles that result from electron transfer.

    • Anions: Gain electrons; net negative charge.

    • Cations: Lose electrons; net positive charge.

  • Electrolytes: Substances that ionize in water, crucial for chemical reactivity, osmotic effects, and nerve/muscle function.

Free Radicals and Antioxidants

  • Free Radicals: Unstable particles with unpaired electrons produced by metabolic processes. Can cause damage, cancer, and aging.

  • Antioxidants: Neutralize free radicals; important dietary sources include vitamins C, E, and selenium.

Isotopes and Radioactivity

  • Isotopes: Variants of elements with different neutron counts; similar chemical properties.

  • Radioisotopes: Unstable isotopes that emit radiation, leading to potential harmful effects such as genetic mutations.

  • Half-life Definitions:

    • Physical Half-life: Time for half of a radioisotope to decay.

    • Biological Half-life: Time for half to disappear from the body.

Organic vs. Inorganic Molecules

  • Organic Molecules: Compounds containing carbon.

  • Inorganic Molecules: Typically do not contain carbon; key inorganic molecules include water (H2O), minerals, and gases like CO2 and O2.

Importance of Water

  • Water Properties:

    • Universal solvent due to polar covalent bonds.

    • Supports life via cohesion, adhesion, and provides thermal stability.

  • Chemical Reactivity: Water participates in various chemical reactions.

Acids, Bases, and pH

  • Acids: Proton donors releasing H+ ions in water.

  • Bases: Proton acceptors that may release OH- ions.

  • pH Scale: Measures concentration of H+ ions:

    • pH = 7 is neutral; less than 7 is acidic (H+ > OH-); greater than 7 is basic (OH- > H+).

  • Buffer Solutions: Stabilize pH levels in biological systems.

Carbon Compounds

  • Functional Groups: Unique clusters of atoms influencing chemical behavior; includes hydroxyl, methyl, carboxyl, amino, phosphate.

  • Macromolecules: Large organic molecules formed by polymerization of monomers:

    • Carbohydrates, lipids, proteins, nucleic acids.

Carbohydrates

  • Function: Primary energy source; structure defined by general formula (CH2O)n.

  • Types:

    • Monosaccharides: Single sugar units (e.g., glucose, fructose).

    • Disaccharides: Two sugar units linked (e.g., sucrose, lactose).

    • Polysaccharides: Long chains (e.g., starch, glycogen).

Lipids

  • Characteristics: Hydrophobic organic molecules; high energy, low hydration. Types include fatty acids, triglycerides, phospholipids, and steroids.

  • Role of Lipids: Long-term energy storage, membrane structure, insulation, and signaling.

Proteins

  • Composition: Polymers of amino acids linked by peptide bonds.

  • Functional Diversity: Enzymes, structural components, signaling molecules, transport, and defense.

  • Protein Structure:

    • Primary: Amino acid sequence.

    • Secondary: Folding and coiling due to hydrogen bonds.

    • Tertiary: 3D structure influenced by R group interactions.

    • Quaternary: Multi-chain structures working together (e.g., hemoglobin).

Enzymes

  • Function: Biological catalysts that speed up reactions by lowering activation energy.

  • Mechanism: Enzymes bind substrates at their active sites to form enzyme-substrate complexes.

Nucleic Acids

  • Function: Store, transport, and translate genetic information; include DNA (double-stranded) and RNA (single-stranded).

  • Monomers: Nucleotides consisting of a sugar, phosphate group, and nitrogenous base.

  • ATP: Main energy currency of the cell, composed of adenine, ribose, and three phosphate groups.