General Biology 1: Cellular Basis of Life

General Biology 1 (BLY 101)

• Course offered by the Microbiology Programme, COAES, Bowen University, Iwo.
• Course credit units: 3
• Lecturer: Adeleke, Olufeyikemi A. (Ph.D.)

Outline for Week One and Two

• Cellular Basis of Life:
  • Cell as fundamental unit of life
  • History of cell discovery
  • Cell theory
  • Cell properties (diversity, size, shape and organization)
  • Differences between prokaryotic and eukaryotic cells
  • Plant and animal cells (similarities and differences)
  • Structure of Plant and Animal cells
• The Microscope:
  • Definition of a microscope
  • History of microscopes
  • Types of microscopes
  • Parts of a microscope and their functions
  • Parts associated with microscopes
  • Precautions for microscope handling

Cellular Basis of Life

• Cells as basic unit of living organisms
• Found in plants, animals, bacteria
• Carry out basic functions
• Cytology is branch of biology studying cells
• Robert Hooke discovered and named cells in 1665
• Anton van Leeuwenhoek witnessed live cells through his handheld microscope
• Matthias Schleiden (1838) concluded that all plants are made of cells
• Theodor Schwann (1839) concluded that all animals are made of cells
• Rudolf Virchow (1858) cells come from pre-existing cells
• Cell Theory:
  • All living things are composed of one or more cells (unicellular or multicellular)
  • Cell is basic unit of life
  • New cells arise from pre-existing cells (through cell division)
• Cell Diversity:
  • Cells vary in size, shape, and internal organization
  • Specialized for specific functions.

Internal Organization of Organisms

• Unicellular organisms: made of a single cell, independent existence
  • Carry out digestion, respiration, reproduction, growth
• Multicellular organisms: made from >1 cell
• Plant cells
• Animal cells
• Cell shapes include spherical, oval, cylindrical, and polyhedral.

Prokaryotic and Eukaryotic Cells

• Prokaryotes:
  • No membrane-bound organelles
  • No true nucleus
  • Examples: Bacterial cells
• Eukaryotes:
  • Well-defined membrane-bound nucleus and organelles
  • Examples: Animal, Plant, Fungi

Types of Cells

• Plant cell (e.g., xylem, phloem, stem cell)
• Animal cell (e.g., nerve, blood, stem)
• Cell size: 1 µm to 200mm (some visible to the naked eye)
• Cell shapes include variable forms depending on the function

Levels of Organization

• Cells contain organelles, which are cell components that perform specific functions

Plant and Animal Cells

• Similarities: Cytoplasm, ribosomes, mitochondria, endoplasmic reticulum, Golgi apparatus, microtubules/microfilaments, flagella, and nucleus

• Differences:

  • Cell wall (present in plant cells)
  • Vacuoles (larger in plant cells)
  • Centrioles (present in animal cells)
  • Chloroplasts (present in plant cells)
  • Plastids (present in plant cells)
  • Cilia (present in animal cells)
  • Shape (often varied between plant and animal cells)
  • Plasma membrane (present in both)
  • Flagella (may be present in some plant and animal cells)
  • Lysosomes (present in animal cells typically)

Functions of Cells and Cell Organelles

• Cell Membrane: thin layer of protein and fat surrounding the cell, semipermeable

• Cell Wall: thick, rigid membrane surrounding plant cells, provides support and structure

• Chloroplast: elongated or disc-shaped organelle with chlorophyll where food (energy from sunlight) is made

• Chlorophyll: molecule using light energy to create glucose and oxygen from water and carbon dioxide

• Lysosome: vesicles with digestive enzymes, digests cell nutrients

• Mitochondrion: converts glucose energy into high-energy ATP for cell use

• Nuclear Membrane: membrane surrounding the nucleus

• Nucleus: spherical body with DNA in chromosomes, controls cell functions.

• Ribosome: small organelles made of RNA, synthesis proteins.

Microscope

• History:
  • Zacharias Janssen (1590): early microscope design
  • Galileo Galilei (1609): improved on the design, added a focusing device to the lens
    • Anton van Leeuwenhoek (1674): improved design, leading to magnified images of 270x.
• Types: compound, stereo, electron (SEM, TEM).
• Microscope Accessories: blank and prepared slides, filters, cover slips.
• Terms: magnification, field of view, ocular
• Parts and functions: eye piece, objective lenses, nose piece, stage, diaphragm, focus knobs, light source (illuminator), condenser, mechanical stage (for placing slides).

This quiz covers the essential concepts related to the cellular basis of life as discussed in General Biology 1 (BLY 101). It includes the history of cell discovery, cell theory, differences between prokaryotic and eukaryotic cells, and the structure of plant and animal cells. Additionally, it explores the definitions and functions of microscopes.