Patho exam 1

Cellular Biology

Organelles

  • Nucleus

    • Holds DNA; considered the center of command for cellular functions.

  • Endoplasmic Reticulum

    • Rough ER: Involved in the assembly of proteins.

    • Smooth ER: Involved in the assembly of lipids.

  • Ribosomes: Responsible for translating amino acids into proteins.

  • Golgi Complex: Packages and ships molecules within the cell.

  • Lysosomes: Removes waste from the cell.

  • Peroxisomes: Involved in lipid metabolism and detoxification.

  • Mitochondria: Considered the power plant of the cell, producing ATP (energy) via glucose.

  • Cytoskeleton: Provides internal framework and shape to the cell.

Metaphors for Cellular Structures

  • Each metaphor relates to a different organelle's function (e.g., 'power plant' for mitochondria).

The Central Dogma of Molecular Biology

  • Replication: Making more DNA.

  • Transcription: Converting DNA to RNA.

  • Translation: Producing protein from RNA.

  • Analogy: Making more DNA is like copying a document, converting DNA to RNA is like typing, and converting RNA to protein is like printing the document.

Differences between Prokaryotes and Eukaryotes

  • Prokaryotes:

    • No nucleus (e.g., bacteria).

  • Eukaryotes:

    • Has a nucleus.

  • Importance of proteins and lipids in maintaining membrane composition.

Cellular Transport

Passive Transport

  • Definition: No ATP required for movement across cell membranes.

  • Types:

    • Simple Diffusion: Movement of small, uncharged molecules (e.g., oxygen, CO2).

    • Facilitated Diffusion: Movement of large/charged and water-soluble molecules (e.g., sodium, potassium, calcium) requires water.

Active Transport

  • Definition: ATP is required to move substances against their concentration gradient.

  • Example: Sodium/Potassium pump.

Cellular Signaling Types

  1. Autocrine: Self-signaling.

  2. Paracrine: Local signaling to nearby cells.

  3. Hormonal: Long-distance signals via the bloodstream.

  4. Neurotransmitter: Signaling between neurons.

  5. Neurohormonal: Communication between neurons and other cells over long distances.

Types of Cellular Division

  • Mitosis: Asexual replication resulting in identical daughter cells.

  • Meiosis: Sexual reproduction resulting in gametes with half the original chromosome count (23 from each parent, totaling 46).

Mitosis Phases

  • Mitosis: Parent cell before replication, duplication of chromosomes, with events through prophase, metaphase, anaphase, and telophase.

Meiosis Phases

  • Meiosis I and II: Prophase, metaphase (pairing of homologous chromosomes), anaphase, and telophase, leading to haploid cells.

Tissue Types

  • 4 Main Tissue Types:

    • Epithelium: Lines surfaces, skin linings.

    • Connective: Comprised of cartilage, ligaments, tendons, etc.

    • Muscular: Smooth, cardiac, and skeletal muscle types.

    • Nervous: Composed of nervous tissues including brain and spinal cord.

Genetics

Universal Genetic Code

  • All organisms use the same DNA code (codons made from nucleotide triplets: A, C, T, G) for protein synthesis.

Codons and Amino Acids

  • Representation of genetic sequences in codon to amino acid translation.

Types of Mutations

  • Definition: Any inherited alteration of genetic material.

  • Types of Mutations:

    • Point Mutation: Change of a single nucleotide.

    • Frameshift Mutation: Alters the reading frame due to insertion or deletion of nucleotides.

    • Inversion: Segment of DNA is reversed within the chromosome.

Causes of Mutations

  • Mutagens: External agents that increase mutation rates (e.g., radiation, chemicals).

Chromosomal Changes

Euploid and Aneuploid Cells

  • Euploid: Normal chromosome multiples; haploid (gametes), diploid (somatic).

  • Aneuploid: Cells with an abnormal number of chromosomes.

Trisomy Examples

  • Trisomy 21: Down syndrome; common features include distinct facial features, heart defects, and developmental delays.

Oncology

Key Definitions

  1. Tumor: Abnormal mass of tissue.

  2. Neoplasm: Dysplastic cell growth.

  3. Benign Tumors: Slow-growing; encapsulated and non-invasive.

  4. Malignant Tumors: Rapid growth; invade local tissues and can metastasize.

Cancer Characteristics

  • Cancer is characterized by uncontrolled cell growth, dysplasia, and the ability to metastasize.

Staging of Tumors

  • TNM Staging System: T (tumor size), N (lymph node involvement), M (distant metastasis). Staging ranges from T0 to T3, N0 to N2, M0 to M2, indicating severity.

Immunity

Innate Immune Responses

  • First Line of Defense: Skin and mucous membranes.

  • Second Line of Defense: Involves innate immune response and inflammatory reactions.

Adaptive Immunity

  • Third Line of Defense: Acquired memory and targeted responses against pathogens through B and T lymphocytes.

Hypersensitivity Reactions

  • Four types, including:

    • Type I: Anaphylactic reactions (IgE mediated).

    • Type II: Cytotoxic reactions (IgG/IgM mediated).

    • Type III: Immune complex reactions.

    • Type IV: Delayed-type hypersensitivity.

Altered Cellular and Tissue Bio

  • Includes definitions for physiological changes (e.g., atrophy, hypertrophy, hyperplasia) and pathological changes (e.g., necrosis).

Important Concepts

  • Apoptosis: Programmed cell death; crucial for normal development and tissue homeostasis.

  • Wound Healing: Involves inflammation, proliferation, and remodeling phases. Dysfunctional healing may arise due to factors such as infection or reduced blood flow.