Cell Diversity Quiz

Cell Diversity

• Cells exhibit diversity in structure and function, adapted for specific tasks.
• Four primary tissue types: epithelial, connective, nervous, and muscle.

Cellular Physiology: Membrane Transport

• Membrane transport includes the movement of substances in and out of cells.
• Two transport methods:
  • Passive transport: No energy required.
  • Active transport: Requires metabolic energy.

Solutions and Transport

• Solutions are homogeneous mixtures; components include:
  • Solvent: Dissolving medium.
  • Solutes: Smaller quantity components.
• Intracellular fluid includes nucleoplasm and cytosol.
• Interstitial fluid is found outside the cell.

Selective Permeability

• Plasma membrane selectively allows certain materials to pass, maintaining internal cell environment.

Passive Transport Processes

• Diffusion: Movement of particles from high to low concentration.
• Types of Diffusion:
  • Simple diffusion: Unassisted movement of lipid-soluble materials or small particles through membrane pores.
  • Osmosis: Simple diffusion of water; water is highly polar and crosses easily.
  • Facilitated diffusion: Requires protein carriers for passive transport.

Filtration

• Filtration involves forcing water and solutes through a membrane via hydrostatic pressure, moving from high to low pressure areas.

Active Transport Processes

• Active transport is necessary for substances unable to diffuse due to size, solubility, or movement against concentration gradient.
• Common forms include solute pumping and bulk transport.

Protein Synthesis

• Genes are DNA segments encoding proteins, essential for body function and structure.
• Proteins act as building materials and enzymes.
• RNA is crucial for protein synthesis, including:
  • Transfer RNA (tRNA): Delivers amino acids to ribosomes.
  • Ribosomal RNA (rRNA): Forms ribosomes.
  • Messenger RNA (mRNA): Carries instructions from DNA to ribosomes.

Transcription and Translation

• Transcription: Converting DNA sequence to mRNA base sequence.
• Translation: Nucleic acid sequence is translated into amino acid sequences, forming proteins.

Body Tissues

• Tissues consist of groups of similar cells performing related functions.
• Four primary tissue types:
  • Epithelium: Covers surfaces, protects, absorbs, and secretes.
  • Connective tissue: Binds, supports, and protects.
  • Nervous tissue: Transmits signals.
  • Muscle: Facilitates movement.

Epithelial Tissues

• Types based on location: coverings, linings, glandular.
• Functions include protection, absorption, filtration, and secretion.
• Characteristics include close cell adherence, a free surface, a basement membrane, and avascularity.

Classification of Epithelium

• Cell Layers:
  • Simple: One layer.
  • Stratified: Multiple layers.
• Cell Shape:
  • Squamous: Flattened cells.
  • Cuboidal: Cube-shaped cells.
  • Columnar: Column-like cells.

Simple Epithelium

• Simple squamous: Flat cells, forming membranes lining body cavities and lungs.
• Simple cuboidal: Cube-like cells, found in glands and kidney tubules.
• Simple columnar: Tall cells with goblet cells, lining the digestive tract.
• Pseudostratified: Appears stratified but is a single layer; often ciliated in the respiratory tract.

Stratified Epithelium

• Stratified squamous: Flattened surface cells, protective covering in areas of friction (skin, mouth).
• Stratified cuboidal: Rare, two layers of cuboidal cells, found in gland ducts.
• Transitional epithelium: Cell shape adapts based on stretching; lines urinary organs.

Glandular Epithelium

• Glands consist of one or more cells that secrete products.
• Endocrine glands: Ductless, secrete hormones.
• Exocrine glands: Use ducts to secrete products like sweat and oil.

Connective Tissue

• Most abundant and widely distributed tissue type.
• Functions include binding, supporting, and protecting body structures.
• Characterized by varying blood supply and extracellular matrix surrounding cells.