Lec 2-3 Cell Theory Notes PDF

Lec 2: The Cell theory Instructor: Roy P. Maribojoc MD, MPH 1665- English Scientist, Robert Hooke, discovered cells while looking at a thin slice of cork. He described the cells as tiny boxes or a honeycomb The word cell comes from the Latin cellula, meaning, a small room. 1838- G...

Lec 2: The Cell theory Instructor: Roy P. Maribojoc MD, MPH 1665- English Scientist, Robert Hooke, discovered cells while looking at a thin slice of cork. He described the cells as tiny boxes or a honeycomb The word cell comes from the Latin cellula, meaning, a small room. 1838- German Botanist, Matthias Schleiden, concluded that all plant parts are made of cells 1839- German physiologist, Theodor Schwann, who was a close friend of Schleiden, stated that all animal tissues are composed of cells. 1858- Rudolf Virchow, German physician, after extensive study of cellular pathology, concluded that cells must arise from preexisting cells. The Cell Theory Complete 1. All organisms are composed of one or more cells. 2. The cell is the basic unit of life in all living things. 3. All cells divide & come from old cells. Lec 3: Basic Cell Biology Instructor: Roy P. Maribojoc MD, MPH All living organism is made up of cells; hence it is known as the basic unit of life. Cell > tissue (group of cells working together) > organ (group of tissue functioning together)> system An average human body is estimated to be composed of trillion of cells. Each cell is composed of parts with its unique functions. Cell parts: Nucleus “control center” Contains the genetic information (chromosomes) Usually spherical; one or more; denser than the surrounding cytoplasm 1 Chromosome is composed of the DNA and associated proteins in the nucleus of eukaryotic cells that carries the genes and functions in the transmission of hereditary information Nuclear membrane Surrounds nucleus Composed of two layers Numerous openings for “nuclear traffic” Nucleolus “little nucleus” Visible when cell is not dividing Contains RNA for protein manufacture Cytosplasm protoplasm the “jelly-like” material that contains the organelles Cytoskeleton scaffolding-like structure in cytoplasm; “cell framework” Composed of microtubules Supports cell and provides shape Aids movement of materials in and out of cells Endoplastic Reticulum (E.R.) Tubular network fused to nuclear membrane Goes through cytoplasm and serves as cell's transport system Types:  Smooth ER – ribosomes not attached to ER=fats and lipid synthesis; detoxification  Rough ER – ribosomes attached to ER= protein synthesis Ribosomes protein synthesis free in the cytoplasm or bound in the endoplasmic reticulum (rough ER) Golgi Bodies packaging center Stacked flattened membranes process and package the macromolecules such as proteins and lipids that are synthesized by the cell Mitochondria the “powerhouse” provides the energy for the cell’s activity 2 Lysosomes “suicide sac” It contains digestive enzyme that destroy worn-out organelles, large particles and invading organisms such as bacteria and viruses Cell membrane The cell boundary composed of lipid bilayer with protein pores and channels, and carbohydrates Surrounds the cytoplasm Lipid bilayer has a hydrophobic tail and hydrophilic heads “Semi-permiable” Prokaryotic vs Eukaryotic cells Prokaryote- An organism characterized by the absence of a distinct, membrane- bound nucleus, and by DNA that is not organized into chromosomes. Sometimes referred to as moneran. (e.g. bacteria) Eukaryote- A single-celled or multicellular organism whose cells contain a distinct membrane-bound nucleus and complex organelles. (e.g fungi, plants, animals) 3 Some examples of the different cells in the human body 4 5