BIOS-150: Human Biology - The Building Blocks of Life

Learning Objectives

  • Body Chemistry

    • Understand how chemical reactions support functions like digestion, nerve signaling, and muscle movement.

    • Describe the importance of maintaining chemical balance (homeostasis) for overall health.

    • Recognize how basic chemistry concepts apply to patient care decisions and lab interpretation.

  • Macromolecules

    • Describe the roles of carbohydrates, proteins, fats, and nucleic acids in the body.

    • Explain how enzymes and ATP help the body process and use nutrients.

    • Understand how macromolecules support patient care in conditions like diabetes and malnutrition.

  • Metabolism

    • Identify metabolism as the set of chemical reactions that convert food into energy.

    • Understand how ATP is produced during cellular respiration and used in activities like muscle contraction and protein synthesis.

    • Recognize how metabolic imbalances affect health and influence treatment decisions.

Introduction to Body Chemistry

  • Every process in the human body relies on chemical reactions and essential elements.

  • Understanding basic chemistry aids healthcare professionals in comprehending how nutrients, water, and minerals support vital functions.

  • Examination of body chemistry is essential for patient care decisions, such as interpreting lab values or understanding electrolyte imbalances.

Body Chemistry and Healthcare

  • Definition: Body chemistry refers to the chemical processes and substances that maintain body function.

  • Importance: Understanding body chemistry is crucial for interpreting symptoms, monitoring lab results, and providing effective treatments.

  • Key Terms:

    • Body chemistry: The study of chemical processes within living organisms.

    • Molecular structure: The arrangement of atoms in a molecule determines its behavior in the body.

    • Biochemical reactions: Chemical processes occurring in living organisms.

    • Metabolism: The set of essential life-sustaining chemical reactions.

Atoms

  • Atoms: The smallest unit of matter and the fundamental building blocks of all substances.

  • Hierarchy of organization:

    • Atoms → Molecules → Cells → Tissues → Organs → Organ Systems → Organism

  • Important atoms in the human body:

    • Iron

    • Phosphorus

    • Zinc

    • Roles include bone health and energy storage.

Molecules

  • Definition: Molecules are formed when two or more atoms bond together.

  • Importance: Molecules are the fundamental building blocks of substances in the body.

  • Examples of important molecules:

    • Glucose ($C6H{12}O_6$)

    • Water ($H_2O$)

    • Proteins

Ions and Electrolytes

  • Ions: Atoms or molecules that lose or gain electrons, resulting in a net charge.

    • Example ions include sodium ions ($Na^+$) and calcium ions ($Ca^{2+}$).

  • Electrolytes: Ions dissolved in water or body fluids crucial for functions like nerve signaling and muscle movement.

    • Example: Sodium chloride (table salt) separates into sodium and chloride ions in water.

Water: An Essential Molecule

  • Importance of Water:

    • Integral to nearly every biological function.

    • Special properties:

    • Polarity: Allows the molecule to dissolve other substances.

    • Cohesion and adhesion: Causes water to stick to itself and other substances.

    • High heat capacity: Helps regulate temperature.

  • Healthcare Example: A patient experiencing dehydration after a hike is treated with IV fluids to restore hydration; understanding how water affects blood volume and temperature is critical in this scenario.

Macronutrients and Micronutrients

  • Macronutrients: Substances required in large amounts for energy, structure, and health maintenance, including:

    • Proteins

    • Carbohydrates

    • Lipids (fats)

    • Nucleic acids

  • Micronutrients: Vitamins and minerals, such as iron, zinc, vitamin D, and vitamin B12, needed in smaller quantities for vital functions.

Chemical Reactions

  • Chemical reactions are ongoing processes in the body, breaking down nutrients, releasing energy, and constructing new molecules.

  • Key Definitions:

    • Chemical reactions: Processes where substances transform into different substances.

    • Reactants: Starting materials in a chemical reaction.

    • Products: The outcomes of a chemical reaction.

    • Types of Reactions:

    • Synthesis reactions: Smaller molecules combine to create larger molecules.

      • Example: $A + B
        ightarrow AB$

    • Decomposition reactions: Larger molecules break down into smaller molecules.

      • Example: $AB
        ightarrow A + B$

    • Healthcare Example: Importance of not eating before surgery as digestion slows down body systems.

Acid-Base Chemistry in Human Biology

  • Impact of Acid-Base Chemistry: Affects medication efficacy, healing times, and various body functions.

  • The body employs a blood buffer system to maintain blood pH within a healthy range of 7.35 to 7.45.

  • Key Terms:

    • Homeostasis: The maintenance of stable internal conditions.

    • pH: A measure of a solution's acidity or basicity.

    • Acidosis: Condition where blood pH falls below 7.35.

    • Alkalosis: Condition where blood pH rises above 7.45.

    • Buffers: Compounds that stabilize pH levels in solutions, acting like a sponge for excess acids or bases.

    • Bicarbonate Buffer System: Involves ions such as bicarbonate ($HCO3^-$), hydrogen ions ($H^+$), and carbonic acid ($H2CO_3$).

Summary: Body Chemistry

  • Essential elements like carbon, oxygen, nitrogen, and hydrogen comprise macronutrients and micronutrients vital for bodily functions.

  • Water is critical for processes like temperature regulation and nutrient transport.

  • Blood pH, hydration, and electrolyte balance depend on molecular properties and chemical reactions driving digestion, muscle contraction, etc.

  • Healthcare professionals must understand these principles to make informed decisions regarding lab results, treatment choices, and patient education.

Introduction to Macromolecules

  • Overview of macronutrients: carbohydrates, fats, proteins, and nucleic acids essential for overall health.

  • Introduction to enzymes and adenosine triphosphate (ATP), crucial for assessing nutritional needs and interpreting lab results.

  • Enzymes: Biological catalysts that facilitate necessary reactions such as digestion and energy production; ATP serves as the immediate energy source, critical for cellular processes.

Adenosine Triphosphate, Macromolecules, and Enzymes

  • Adenosine Triphosphate (ATP): The primary energy carrier in cells, essential for powering cellular activities (e.g., muscle contraction and nerve signaling).

  • Essential Macromolecules:

    • Carbohydrates

    • Proteins

    • Fats (lipids)

    • Nucleic acids

  • Enzymes: Proteins that accelerate reactions, necessary for metabolism and nutrient utilization.

    • Catalysts enhance reaction rates without being consumed in the process.

Role of Carbohydrates

  • Carbohydrates: The body's favored energy source, particularly for the brain and muscles.

    • Break down into glucose during cellular respiration to produce ATP.

    • Distinction between:

    • Simple carbohydrates (quick energy)

    • Complex carbohydrates (sustained energy)

    • Healthcare Example: Monitoring glucose levels in diabetic patients to prevent energy crashes.

    • Complex Carbohydrates: Gradually release energy; examples include starches (stored sugars).

Role of Proteins

  • Proteins: Crucial for muscle building, tissue repair, immune support, and enzyme creation.

    • Composed of amino acids, obtained through digestion.

    • Healthcare Example: Protein-rich diets for patients with pressure ulcers to promote healing.

Role of Fats

  • Essential Functions of Fats:

    • Long-term energy storage

    • Absorption of fat-soluble vitamins (A, D, E, K)

    • Protection of organs and temperature insulation

    • Hormone production (e.g., estrogen, testosterone)

  • Cellular Role:

    • Cell membranes composed of a phospholipid bilayer regulating nutrient flow and cell signaling.

    • Cholesterol contributes to membrane fluidity.

    • Healthcare Example: Educating cardiac patients on replacing saturated fats with healthier options to lower heart disease risk.

Role of Nucleic Acids

  • Nucleic Acids: Large molecules vital for the storage and transmission of genetic information.

    • DNA: Stores genetic information crucial for growth, development, and reproduction.

    • RNA: Interprets DNA to facilitate protein production.

  • Healthcare Implications:

    • Mutations in DNA can lead to cancer and genetic disorders.

    • Applications in diagnosis and treatment, such as gene therapy and chemotherapy.

Role of Enzymes

  • Definition: Special proteins that expedite chemical reactions in the body.

  • Enzyme Functionality: Each enzyme has a unique structure to bind with specific substrates (lock and key model).

  • Enzymatic Breakdown Example:

    • Amylase for carbohydrates, lipase for fats, protease for proteins.

  • Importance: Without enzymes, vital chemical reactions could not occur efficiently.

Angiotensin-Converting Enzyme (ACE)

  • ACE regulates blood pressure and fluid balance by converting angiotensin I to angiotensin II.

    • Angiotensin II constricts blood vessels, raising blood pressure in low-pressure situations (e.g., dehydration).

  • ACE Inhibition:

    • Mechanism: Medications that block ACE decrease the formation of angiotensin II, relaxing blood vessels and lowering blood pressure (e.g., lisinopril).

Summary: Macromolecules

  • The body relies on macronutrients: carbohydrates, proteins, fats, and nucleic acids for energy, growth, repair, and genetic communication.

  • Enzymes facilitate these processes while ATP is the primary energy source for cells.

  • This understanding aids healthcare professionals in assessing nutrition and managing diseases.

Introduction to Metabolism

  • Definition: Metabolism encompasses chemical processes converting food into energy and building materials for bodily functions.

  • Involves cellular metabolism, where nutrients are processed to produce ATP.

  • Importance for healthcare: Understanding metabolism elucidates body responses to food, treatments, and medications.

Metabolism Terminology

  • Mnemonic: My Cat Ate Cookies Every Morning!

    • M - Metabolism: The total of all chemical processes converting food into energy.

    • C - Catabolism: Breaking down molecules (energy release).

    • A - Anabolism: Building molecules (energy usage).

    • C - Cellular Metabolism: All cell’s chemical reactions.

    • E - Enzymes: Speeding up reactions.

    • M - Mitochondria: ATP production powerhouse of the cell.

Importance of Adenosine Triphosphate (ATP)

  • ATP: The main energy carrier for cellular activities, produced by breaking down glucose during cellular respiration.

  • Healthcare Example: Fluid replacement in dehydrated patients demonstrates the consequences of inadequate ATP production on body systems.

Metabolism: Anabolism vs Catabolism

  • Metabolism includes both anabolism (building molecules) and catabolism (breaking down molecules).

    • Functions:

    • Anabolism: Growth, repair, energy storage.

    • Catabolism: Energy production; releases ATP.

    • Examples:

    • Anabolic: Building proteins from amino acids.

    • Catabolic: Breaking down proteins for energy.

Metabolism, Cellular Metabolism & Cellular Respiration

  • Metabolism: All chemical reactions to maintain life—whole body.

  • Cellular Metabolism: Specific reactions that occur inside cells, managing their life.

  • Cellular Respiration: Process converting nutrients into ATP, specifically in mitochondria.

    • Major stages include glycolysis, pyruvate oxidation, Krebs cycle, and electron transport.

Sodium-Potassium Pump

  • Function: A membrane protein that uses ATP to transfer sodium out of cells and potassium into cells, maintaining ionic balance necessary for metabolic processes.

  • Healthcare Relevance: Critical for kidney filtration, neuron communication, and muscle contraction.

Sodium-Potassium Pump with Metabolism

  • Phone Analogy:

    • Metabolism (entire functions) = the phone’s overall operation.

    • Cellular Metabolism (individual cells) = apps functioning.

    • Sodium-Potassium Pump = system maintaining internal settings for app functionality.

Macronutrients' Role in Metabolism

  • Macronutrients are essential fuel for metabolism:

    • Carbohydrates provide quick energy.

    • Fats offer long-term energy and protection.

    • Proteins are critical for building and repairing tissues.

  • Healthcare Example: Management of carbohydrate intake in diabetic patients to avoid fluctuations in blood sugar.

Metabolic Regulation

  • Hunger Signaling: Ghrelin from the stomach signals hunger; low blood sugar reinforces this signal.

  • Satiation Signaling: Hormones like leptin and insulin indicate fullness, regulating energy balance and metabolic health.

Metabolic Issues

  • Common metabolic disorders:

    • Type 1 Diabetes: The immune system attacks insulin-producing cells in the pancreas.

    • Type 2 Diabetes: Insulin resistance; cells do not respond effectively to insulin.

    • Hypothyroidism: Underactive thyroid slowing metabolic rate.

    • Metabolic Syndrome: Cluster of health issues including high blood pressure, blood sugar, and abnormal cholesterol presenting risks for heart disease and diabetes.

  • Healthcare Example: Understanding thyroid hormones aids patient education and management of hypothyroidism symptoms.

Metabolic Disorders: Type 1 & Type 2 Diabetes

  • Understanding Diabetes: Group of diseases affecting blood sugar regulation linked to insulin.

  • Type 1 Diabetes: Autoimmunity leads to insulin deficiency requiring injections for blood glucose control.

  • Type 2 Diabetes: Characterized by insulin resistance; lifestyle adjustments key to management.

The Role of Healthcare Professionals in Metabolic Health

  • Healthcare professionals educate on nutrition and monitor medication responses affecting metabolism.

  • Healthcare Example: Nutritional counseling post-surgery to ensure metabolic activity for healing.

Summary: Metabolism

  • Definition: Metabolism is the chemical processes transforming food into energy for bodily functions.

  • Core Nutrients: ATP production via metabolism is crucial for sustaining biological activity.

  • Disruptions lead to conditions like diabetes and metabolic syndrome. Understanding these processes allows professionals to optimize patient care and recovery.