Cytology Lecture Overview

Study Notes

Cytology is the branch of biology and medicine that studies cell structure and function.
Organisms can be unicellular or multicellular.
Biological organization ranges from organelles to cells, tissues, organs, systems, and organisms. This is arranged from the simplest to the most complex.

The biological levels of organization of living things are arranged from simplest to most complex: organelle, cells, tissues, organs, systems, and organisms.

Water makes up about 70% of a cell's weight and acts as a solvent for biochemical reactions.
Organic materials in cells include carbohydrates, lipids, proteins, and nucleic acids.
Inorganic materials include ions like Ca²⁺, PO₄³⁻, Na⁺, and Mg²⁺.
Other minerals like Co²⁺, Cu²⁺, Cu³⁺, I⁻, Mn²⁺, and Zn²⁺ are also present.

Smooth endoplasmic reticulum (SER): Network of tubules involved in lipid synthesis and detoxification.
Rough endoplasmic reticulum (RER): Network of flattened sacs with ribosomes; involved in protein synthesis and secretion.
Ribosomes: Particles that synthesize proteins from amino acids; can be free or bound to the RER. Ribosomes are composed of large and small subunits.
Golgi apparatus: Flattened, disk-shaped sacs that process and package proteins. It has a cis face and a trans face.
Lysosomes: Membrane-bound organelles containing enzymes that break down waste materials and cellular components.
Mitochondria: "Powerhouses of the cell"; generate energy (ATP) through cellular respiration; have two membranes (inner and outer) and cristae.
Cytoskeleton: A network of protein filaments that provides structural support and facilitates cell movement; includes microfilaments, microtubules, and intermediate filaments.
Nucleus: The control center of the cell containing the genetic material (DNA) transmitted to offspring. It has an outer and inner membrane and nucleolus.
Chromatin: DNA combined with proteins; is found within the nucleus.
Nucleolus: A structure within the nucleus where ribosomes are assembled.
Plasma membrane: A thin membrane surrounding the cell, separating the cell's contents from its environment; acts as a barrier and regulates transport. This membrane is about 0.005 μm (5nm) thick.