Unit 3 Cells

3.1 Cell Theory

Definition: The cell theory is a fundamental concept in biology that states the following:

  • All living organisms are composed of one or more cells.

  • The cell is the basic unit of life.

  • All cells arise from existing cells.

3.2 Prokaryotes vs Eukaryotes

Prokaryotes:

  • Lack of nucleus and other membrane-bound organelles

  • Generally smaller and simpler than eukaryotic cells

  • example: bacteria and archaea

Eukaryotes:

  • Have a true nucleus and membrane-bound organelles

  • larger and more complex than prokaryotic cells

  • example: animal cells, plant cells, fungi, and protists

3.3 Microbiology Lab

Purpose: to study microorganisms (bacteria, viruses, fungi, protozoa)

Key techniques:

  • culturing bacteria on agar plates

  • Microbiology techniques to observe cell structures

  • staining methods (e.g., Gram staining ) to differentiate types of bacteria

3.4 organelles (animal vs plant)

common organelles (both animal and plant cells):

  • Nucleus, Mitochondria, endoplasmic reticulum (ER), Golgi apparatus, and ribosomes.

Unique to Plant Cells:

  • Chloroplast ( for photosynthesis)

  • cell wall (provides structure and support)

  • Large central vacuole (stores H2O and nutrients)

Unique to Animal Cells:

  • Lysosomes (for digestion of waste materials)

  • Centrioles (involved in cell division)

3.5 Cell Adaptations

cells have evolved various adaptations to perform specific functions

examples include

  • Muscle cells: are elongated and contain many mitochondria for energy

  • red blood cells have long extensions to absorb water and minerals with more efficiency

3.6 cell specialization

process by which generic cells change into specific cell types to perform distinct functions in multicellular organisms

examples include:

  • nerve cells: specialized for transmitting nerve impulses

  • Immune Cells: specialize in identifying and responding to pathogens

  • Epithelial cells: form protective layers on body surfaces and organs>