Understanding Cell Physiology and Function

Aug 24, 2024

Review flashcards

Human Physiology - Chapter 2: Cell Physiology

Levels of Organization

  • Chemical Level: Atoms form molecules.
  • Cellular Level: Molecules build cells, which are the basic units of life.
  • Organ System Perspective: Understanding organ systems requires knowledge of organs, tissues, and cells.

Basics of Cells

  • Cell Size: Human cells range from 10 to 20 micrometers in diameter.
    • Largest cell: Human egg (~140 micrometers).
    • Neurons and muscle fibers can be longer but are typically not wider.
  • Importance of Size: Provides perspective on cell structures.

Major Subdivisions of a Cell

Plasma Membrane

  • Also known as the cell membrane.
  • Separates intracellular fluid (ICF) from extracellular fluid (ECF).
  • Selectively permeable: Controls molecule movement between ICF and ECF.

Nucleus

  • Usually central; contains DNA (genetic blueprint).
  • Double-layered membrane (two phospholipid bilayers).
  • Directs protein synthesis, influencing cell function.

Cytoplasm

  • Includes organelles and cytosol (fluid part).
  • Organelles perform specialized functions.
  • Separation of chemical reactions is crucial.

Cell Organelles

Endoplasmic Reticulum (ER)

  • Rough ER: With ribosomes; synthesizes proteins and lipids.
  • Smooth ER: No ribosomes; involved in lipid synthesis and detoxification.

Golgi Complex

  • Processes and sorts ER products into final form.
  • Produces vesicles for transport inside or outside the cell.

Lysosomes

  • Contain hydrolytic enzymes for digesting cellular debris.

Peroxisomes

  • Contain oxidative enzymes to detoxify substances.

Mitochondria

  • Double membrane; site of ATP production.
  • Inner Membrane: Contains electron transport chain.
  • Matrix: Site for the citric acid cycle.
  • Involved in apoptosis.

Cellular Respiration

Glycolysis

  • Occurs in cytosol.
  • Breaks glucose into 2 pyruvic acids.
  • Produces 2 ATP and hydrogen carriers.

Citric Acid Cycle

  • Occurs in mitochondrial matrix.
  • Converts pyruvic acid to acetyl CoA.
  • Produces CO2, hydrogen carriers, and 2 ATP.

Oxidative Phosphorylation

  • Occurs on the inner mitochondrial membrane.
  • Electron Transport Chain: Transfers electrons from hydrogen carriers.
  • Chemiosmotic Mechanism: Produces 28 ATP using ATP synthase.
  • Oxygen is the final electron acceptor, forming water.

Key Processes and Concepts

  • Exocytosis and Endocytosis: Processes for moving materials across the plasma membrane.
  • ATP Production: Essential for cellular functions like muscle contraction and molecule transport.
  • Metabolic Water: Water produced from cellular respiration.

Additional Notes

  • Glucose is a primary energy source, but fats and proteins can also be used in cellular respiration.
  • High ATP yield comes from oxidative phosphorylation.
  • Anaerobic conditions lead to limited ATP production through glycolysis.

These notes provide a comprehensive overview of cell physiology as discussed in the lecture. They cover the key concepts and structures necessary to understand cellular function and energy production.