Exam 1 Study Gudie

Biological Hierarchy and Homeostasis

Biological Hierarchy

The biological hierarchy describes the organization of living things from the simplest to the most complex levels. Understanding this hierarchy is essential for grasping how life functions at different scales.

• Levels: Atoms → Molecules → Organelles → Cells → Tissues → Organs → Organ Systems → Organism

• Importance: Each level builds on the previous, allowing specialization and complex functions.

Homeostasis

Homeostasis is the process by which living organisms maintain stable internal conditions necessary for survival.

• Negative Feedback Mechanisms: These mechanisms counteract changes, keeping conditions within a narrow range.

• Components of Reflexive Action:

  • Stimulus → Receptor → Control Center → Effector → Response

• Example: Regulation of body temperature.

Anatomy vs. Physiology

Definitions and Relationship

Anatomy is the study of the structure (form) of body parts, while physiology is the study of their function. The form of a structure is closely related to its function.

• Example: The anatomy of the heart (chambers, valves) enables its physiological function (pumping blood).

Organ Systems of the Human Body

Overview of 11 Organ Systems

The human body consists of 11 major organ systems, each with specific functions and components.

• Systems: Integumentary, Skeletal, Muscular, Nervous, Endocrine, Cardiovascular, Lymphatic, Respiratory, Digestive, Urinary, Reproductive

• Key Point: Know the general functions and major organs of each system.

Anatomic Position, Sections, and Planes

Anatomic Position

The anatomic position is a standardized posture used as a reference in anatomy: standing upright, facing forward, arms at sides, palms facing forward.

• Importance: Provides consistency in anatomical descriptions.

Body Planes and Sections

Body planes are imaginary lines used to divide the body for anatomical study.

• Coronal (Frontal) Plane: Divides body into anterior and posterior parts.

• Transverse Plane: Divides body into superior and inferior parts.

• Sagittal Plane: Divides body into left and right parts.

• Oblique Plane: Cuts at an angle.

Medical Imaging

Medical imaging techniques (e.g., MRI, CT scans) are used to visualize internal structures and are important for diagnosis.

Anatomic Directional Terminology

Directional Terms

Directional terms describe the locations of structures relative to other structures or locations in the body.

• Examples: Anterior/posterior, superior/inferior, medial/lateral, proximal/distal, superficial/deep

Regional Terms

Regional terms refer to specific areas of the body (e.g., brachial for arm, femoral for thigh).

Body Cavities and Serous Membranes

Body Cavities

Body cavities protect organs and allow for changes in organ size and shape.

• Posterior (Dorsal) Cavity:

  • Cranial cavity (brain)

  • Vertebral cavity/canal (spinal cord)

• Ventral Body Cavity:

  • Thoracic cavity (heart, lungs)

  • Pleural cavity (lungs)

  • Pericardial cavity (heart)

  • Mediastinum (central thoracic region)

  • Abdominopelvic cavity (digestive, urinary, reproductive organs)

  • Abdominal cavity

  • Pelvic cavity

Serous Membranes

Serous membranes line body cavities and cover organs, reducing friction.

• Layers: Parietal (lines cavity) vs. Visceral (covers organ)

• Serous Fluid: Lubricates and protects

Atoms, Elements, and Chemical Bonds

Atomic Structure

Atoms are the basic units of matter, composed of protons, neutrons, and electrons.

• Atomic Number: Number of protons

• Atomic Mass: Number of protons + number of neutrons

• Isotopes: Atoms of the same element with different numbers of neutrons

• Octet Rule: Atoms tend to have eight electrons in their valence shell

Types of Chemical Bonds

• Ionic Bonds: Electrons are transferred; forms ions (cations and anions)

• Covalent Bonds: Electrons are shared between atoms

  • Nonpolar Covalent: Equal sharing

  • Polar Covalent: Unequal sharing

• Hydrogen Bonds: Weak attractions between polar molecules, important in water and biological molecules

Water and Its Properties

Water as a Polar Molecule

Water's polarity allows it to form hydrogen bonds, which are crucial for its unique properties.

• Cohesion/Adhesion: Water molecules stick to each other and to other surfaces

• High Specific Heat: Water resists temperature changes

• Ice Floats: Solid water is less dense than liquid water

• Solvent of Life: Water dissolves many substances

pH, Acids, Bases, and Buffers

pH measures the concentration of hydrogen ions in a solution.

• Acids: Donate H+

• Bases: Accept H+

• Buffers: Stabilize pH by absorbing or releasing H+

Biological Molecules

Four Classes of Biological Molecules

Biological molecules are essential for structure and function in living organisms.

• Lipids:

  • Energy-rich due to many hydrogen atoms

  • Types: Triglycerides, steroids, phospholipids

  • Saturated vs. Unsaturated fats

  • Phospholipid structure is key for membranes

• Carbohydrates:

  • Glucose is a primary energy source

  • Polysaccharides: Starch, glycogen, cellulose

• Proteins:

  • Made of 20 different amino acids

  • Levels of structure: Primary, secondary, tertiary, quaternary

  • Denaturation leads to loss of function

• Nucleic Acids:

  • DNA and RNA; made of nucleotides (sugar, phosphate, nitrogenous base)

  • Complementary base pairing: A-T (A-U in RNA), C-G

  • Central Dogma: DNA → RNA → Protein

Adenosine Triphosphate (ATP)

ATP is the energy currency of the cell, used in nearly all cellular processes.

• Energy released when electrons move from less to more electronegative atoms

• ATP stores and releases energy for cellular work

Cellular Respiration

Aerobic Cellular Respiration

Cells extract energy from glucose through a series of metabolic pathways.

• Four Stages:

  1. Glycolysis

  2. Pyruvate Oxidation

  3. Citric Acid (Krebs) Cycle

  4. Oxidative Phosphorylation (Electron Transport Chain & Chemiosmosis)

• Electron transport chain creates a proton gradient used to synthesize ATP

Fermentation

Fermentation allows cells to produce ATP without oxygen.

• Important in anaerobic conditions

Alternative Energy Sources

• Cells can use fats and proteins for energy in addition to carbohydrates

Cell Structure and Function

Prokaryotes vs. Eukaryotes

Cells are classified as prokaryotic or eukaryotic based on their structure.

• Prokaryotes: No membrane-bound organelles (e.g., bacteria)

• Eukaryotes: Have membrane-bound organelles (e.g., nucleus, mitochondria)

• Importance: Compartmentalization allows specialized functions

Cell Size

Cells are small to maximize surface area to volume ratio (SA/V), facilitating efficient exchange of materials.

Cell Parts and Functions

Each cell part has a specific function; refer to provided tables for details.

Cell Membrane Structure and Transport

Phospholipid Bilayer

The cell membrane is primarily composed of a phospholipid bilayer, which provides a selectively permeable barrier.

• Phospholipids: Arranged with hydrophilic heads facing outward and hydrophobic tails inward

• Selective Permeability: Allows some substances to pass more easily than others

Membrane Transport Mechanisms

• Passive Transport: No energy required; substances move down their concentration gradient

  • Simple Diffusion: Direct movement through membrane

  • Facilitated Diffusion: Movement via channel or carrier proteins

• Active Transport: Energy required; substances move against their concentration gradient

  • Example: Sodium-potassium pump

• Bulk Transport: Movement of large substances

  • Endocytosis: Bringing substances into the cell

  • Exocytosis: Expelling substances from the cell

Table: Comparison of Membrane Transport Mechanisms

Type	Energy Required?	Direction	Example
Simple Diffusion	No	Down gradient	O2 and CO2 movement
Facilitated Diffusion	No	Down gradient	Glucose transport via carrier protein
Active Transport	Yes	Up gradient	Sodium-potassium pump
Endocytosis	Yes	Into cell	Phagocytosis
Exocytosis	Yes	Out of cell	Neurotransmitter release

Key Equations and Concepts

• Atomic Mass: $\text{Atomic Mass} = \text{Number of Protons} + \text{Number of Neutrons}$

• Central Dogma: $\text{DNA} \rightarrow \text{RNA} \rightarrow \text{Protein}$

• ATP Synthesis (Chemiosmosis): $\text{ADP} + \text{P}_i \rightarrow \text{ATP}$

Additional info: Academic context and examples have been added to clarify and expand upon the original notes.