Untitled Quiz

Cytology and Genetic Course

• Cytology, also known as cell biology, studies cells.
• It's crucial for researchers in vaccine and medicine development.
• The cell is the basic unit of life.
• Plant cells have cell walls and plastids, unlike animal cells which lack these components.
• Prokaryotic cells lack membrane-bound organelles, unlike eukaryotic cells.
• Plants are unique eukaryotes capable of producing their own food (autotrophic).

Historical Review

• Cytology emerged as a distinct biological field by the late 19th century.
• Before the 19th century, figures like Aristotle and Paracelsus considered few fundamental components in plants and animals
• Leonardo da Vinci (1485) used lenses to view small objects.
• Jan Swammerdam (1658) described cells (blood cells).

Further Development of Cytology

• Marable (1808): Found plants have membranous cellular tissues.
• Turpin (1826): Observed cell division.
• Robert Brown (1826, 1831): Discovered and described the nucleus as a central part of plant cells.
• Felix Dujardin (1835): Described protoplasm in protozoa.
• Schleiden (1838) and Schwann (1839): Established basic cell theory for plants and animals, respectively.
• Rudolf Virchow (1858): Stated all cells arise from preexisting cells.

Additional Key Developments

• Robert Hooke (1665-1703): Studied cork and coined the term "cells."
• Antonie van Leeuwenhoek (1632-1723): Discovered protozoa, red blood cells, etc.
• Fontana (1781): Described the nucleolus.
• 19th century: Considered the classical era for cytological investigations.
• Purkinje (1840): Named the cell contents as protoplasm.
• Haecked (1866): Named plastids.
• Strasburger (1875): Described chromosomes.

Principles of Cell Theory

• All living things are made of cells.
• Cells are the smallest living units of structure and function in organisms.
• All cells arise from preexisting cells.
• Most cells are microscopic.

Cell Surface Area

• Larger surface area to volume ratio is advantageous for cells.
• A smaller cell can more effectively exchange substances with its environment.

Viruses Versus Cells

• Viruses are transitional between living and nonliving things.
• Viruses infect both prokaryotic and eukaryotic cells.
• Viruses are metabolically inert but active in hosts.
• Viruses are simpler than cells in structure and life cycle.
• Virus size is smaller than bacteria.

Classification of Organisms

• Cellular organisms (except some plants like rhizopus and vaucheria) have cellular organization.
• They may be unicellular or multicellular.
• Prokaryotic cells lack a true nucleus.
• Examples include certain bacteria, blue-green algae and PPLO.
• PPLO are bacteria-like organisms.

Prokaryotic Cells (Bacteria)

• Bacteria are microscopic, unicellular, and lack chlorophyll.
• They can be saprophytic or parasitic.
• Average size is 1.25 μm.
• Smallest bacteria are 0.15-0.30 μm in length; largest up to 13-15 μm.
• Forms include coccus, bacillus, and spirillum.

Cytology Key Terms

• Karyokinesis: Nucleus division
• Cytokinesis: Cytoplasm division
• Diploid: Two sets of chromosomes (somatic cells).
• Haploid: One set of chromosomes (gametes).
• Crossing over: Genetic material exchange during meiosis.
• Homologous chromosome: Pair of chromosomes with same size and identical gene sequences.
• Phenotype: Observable characteristics of organism.
• Genotype: Genetic makeup of organism.
• Tonoplast: Membrane surrounding the vacuole.
• Unit membrane: Basic structure of cell membrane.

Plant and Animal Cell Differences

Eukaryotic vs. Prokaryotic Cells

Eukaryotic Cell Organelles (Presence/Absence, Size)