Biology 109: Biology of the Human Organism – Final Exam Study Guide

Biology of the Human Organism: Final Exam Study Guide

Introduction to Biology

Biology is the study of living organisms, their structure, function, growth, origin, evolution, and distribution. Understanding the characteristics of life and levels of organization is foundational for anatomy and physiology.

• Characteristics of Living Things: Organization, metabolism, responsiveness, growth, reproduction, adaptation.

• Levels of Organization: Cell → Tissue → Organ → Organ System → Organism.

• Scientific Method: Hypothesis, experiment, observation, conclusion.

Chemistry of Living Things

Cells rely on chemical reactions for energy and structure. Understanding macromolecules and metabolism is essential.

• Carbohydrates: Main energy source; broken down via catabolism to release energy.

• Proteins: Structure, enzymes, signaling; amino acids are building blocks.

• Lipids: Energy storage, cell membranes, signaling.

• Enzymes: Biological catalysts that speed up reactions.

• Metabolism: Sum of all chemical reactions; includes catabolism (breakdown) and anabolism (synthesis).

Structure and Function of Cells

Cells are the basic unit of life. Their structure determines their function.

• Prokaryotic vs. Eukaryotic Cells: Prokaryotes lack a nucleus; eukaryotes have membrane-bound organelles.

• Cell Membrane: Phospholipid bilayer; controls entry/exit of substances.

• Mitochondria: Site of cellular respiration; produces ATP.

• Endomembrane System: Includes ER, Golgi apparatus, lysosomes; involved in protein and lipid processing.

• Diffusion & Osmosis: Passive transport mechanisms for molecules across membranes.

From Cells to Organ Systems

Cells form tissues, which organize into organs and organ systems, each with specialized functions.

• Types of Tissues: Epithelial, connective, muscle, nervous.

• Organ Systems: Groups of organs working together (e.g., digestive, respiratory, circulatory).

• Homeostasis: Maintenance of stable internal environment.

• Negative Feedback: Mechanism to maintain homeostasis (e.g., temperature regulation).

The Skeletal System

The skeletal system provides structure, protection, and facilitates movement.

• Types of Bones: Long, short, flat, irregular.

• Bone Structure: Compact vs. spongy bone; marrow produces blood cells.

• Joints: Allow movement; classified by structure and function.

The Muscular System

Muscles enable movement, maintain posture, and produce heat.

• Types of Muscle: Skeletal (voluntary), cardiac (heart), smooth (involuntary).

• Muscle Contraction: Sliding filament theory; actin and myosin interaction.

• Neuromuscular Junction: Site where nerve stimulates muscle.

Blood

Blood transports nutrients, gases, and waste; plays a role in immunity and homeostasis.

• Components: Red blood cells, white blood cells, platelets, plasma.

• Functions: Oxygen transport, immune defense, clotting.

The Heart and Blood Vessels

The cardiovascular system circulates blood throughout the body.

• Heart Structure: Chambers (atria, ventricles), valves, septum.

• Blood Vessels: Arteries (away from heart), veins (toward heart), capillaries (exchange).

• Blood Pressure: Force of blood against vessel walls.

The Immune System and Mechanisms of Defense

The immune system protects against pathogens and maintains health.

• Innate Immunity: Non-specific defenses (skin, mucous membranes, phagocytes).

• Adaptive Immunity: Specific responses (lymphocytes, antibodies).

• Antigens: Substances that trigger immune response.

• Vaccines: Stimulate adaptive immunity.

The Respiratory System

The respiratory system exchanges gases between the body and environment.

• Organs: Nose, pharynx, larynx, trachea, bronchi, lungs.

• Gas Exchange: Occurs in alveoli; oxygen in, carbon dioxide out.

• Breathing Regulation: Controlled by brainstem; responds to CO2 levels.

The Nervous System

The nervous system integrates and controls body functions.

• Central Nervous System (CNS): Brain and spinal cord.

• Peripheral Nervous System (PNS): Nerves outside CNS; includes somatic and autonomic systems.

• Neurons: Transmit electrical signals; synapses are communication points.

• Reflex Arcs: Automatic responses to stimuli.

Sensory Mechanisms

Sensory systems detect and interpret environmental stimuli.

• Types of Sensory Receptors: Mechanoreceptors, chemoreceptors, photoreceptors, thermoreceptors.

• Special Senses: Vision, hearing, taste, smell, equilibrium.

The Endocrine System

The endocrine system regulates body functions via hormones.

• Major Endocrine Glands: Pituitary, thyroid, adrenal, pancreas, gonads.

• Hormones: Chemical messengers; regulate growth, metabolism, reproduction.

• Feedback Mechanisms: Negative and positive feedback control hormone levels.

The Digestive System and Nutrition

The digestive system breaks down food and absorbs nutrients.

• Organs: Mouth, esophagus, stomach, intestines, liver, pancreas.

• Digestion: Mechanical and chemical breakdown of food.

• Absorption: Nutrients absorbed in small intestine.

The Urinary System

The urinary system removes waste and regulates water and electrolyte balance.

• Organs: Kidneys, ureters, bladder, urethra.

• Nephron: Functional unit of kidney; filters blood, forms urine.

• Homeostasis: Maintains fluid and electrolyte balance.

The Reproductive System

The reproductive system enables production of offspring and regulates sexual function.

• Male System: Testes, vas deferens, prostate, penis.

• Female System: Ovaries, fallopian tubes, uterus, vagina.

• Hormonal Regulation: Sex hormones control development and reproduction.

Genetics and Inheritance

Genetics explains how traits are passed from parents to offspring.

• DNA: Genetic material; codes for proteins.

• Genes: Units of heredity; located on chromosomes.

• Mendelian Inheritance: Dominant and recessive traits.

Key Terms and Concepts

• Homeostasis

• Prokaryotic vs. Eukaryotic

• Diffusion vs. Osmosis

• Endomembrane System

• Negative Feedback

• Immune System: Innate vs. Adaptive Immunity

• Hormones and Endocrine Glands

• Nephron Structure

• ADH (Antidiuretic Hormone)

Sample Table: Comparison of Prokaryotic and Eukaryotic Cells

Feature	Prokaryotic Cells	Eukaryotic Cells
Nucleus	Absent	Present
Organelles	Few (e.g., ribosomes)	Many (mitochondria, ER, etc.)
Size	Small (1-10 μm)	Larger (10-100 μm)
Examples	Bacteria, Archaea	Plants, Animals, Fungi

Sample Equation: Cellular Respiration

The process by which cells convert glucose and oxygen into energy:

$\text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \rightarrow 6\text{CO}_2 + 6\text{H}_2\text{O} + \text{ATP}$

Additional info:

• Some topics were expanded for clarity and completeness, such as the structure and function of organ systems, and the role of feedback mechanisms in homeostasis.

• Definitions and examples were added to make the notes self-contained and suitable for exam preparation.