Cell Theory PDF

1 MICROSCOPE: The invention of the microscope led to the discovery of the cell Robert Hooke English physicist He first described cells He used a microscope he built to examine a thin slice of cork...

1 MICROSCOPE: The invention of the microscope led to the discovery of the cell Robert Hooke English physicist He first described cells He used a microscope he built to examine a thin slice of cork Cellulae (Latin) – small rooms Cork Cells English scientist Robert Hooke published Micrographia in 1665. In it, he illustrated the smallest complete parts of an organism, which he called cells. Antoine van Leeuwenhoeck (1676) Dutch businessman and scientist He observed the first living cells “Animalcules” – tiny animals Father of Microbiology Matthias Schleiden (1838) German Botanist He studied a variety of plants and concluded that all plants are “aggregates of fully individualized, independent, separate beings, namely the cells themselves.” Theodor Schwann German physician 1839 He reported that all animals are also made of cells Rudolf Virchow German physician 1855 He induced that “the animal arises only from an animal and the plant from a plant.” Cell Theory: The combined work of Schleiden, Schwann and Virchow make up what is now known as the Cell Theory. The Cell Theory 1. The cell is the basic unit of life. 2. All organisms are made up of one or more cells. 3. All cells come from pre-existing cells. Modern Cell Theory 1. All living things are made of cells. o May be unicellular or multicellular  1 2. The cell is the basic unit of life. o structurally and functionally o Life doesn’t exist at a more basic form than a cell. 3. All cells are formed from pre-existing cells. o Cells do not spontaneously generated. 4. Hereditary information is passed on during cell division. o Each cell is a copy of its parent cell. 5. All the cells have the same basic chemical composition. o There are different types, but they are similar at their core. 6. Energy flow occurs within cells. o All metabolic and biochemical processes occur within the cells.  1 Prokaryotic Cell Pro – Before Karyon – nucleus single-celled (unicellular) organism that lacks a nucleus, or any other membrane-bound organelle. Eukaryotic Cell Eu – true Karyon – nucleus has a membrane-bound nucleus and other membrane-bound compartments or sacs, called organelles, which have specialized functions All cells share four key components: The plasma membrane is an outer covering that separates the cell’s interior from its surrounding environment. Cytoplasm consists of the jelly-like cytosol inside the cell, plus the cellular structures suspended in it. In eukaryotes, cytoplasm specifically means the region outside the nucleus but inside the plasma membrane. DNA is the genetic material of the cell. Ribosomes are molecular machines that synthesize proteins. ENDOSYMBIOTIC THEORY major theme in the origin of eukaryotes one cell engulfs another such that the engulfed cell survives and both cells benefit a symbiotic relationship can result in two organisms that depend on each other so completely that neither could survive on its own Prokaryotic Cells found in both Domain Archaea and Bacteria are unicellular organisms that lack membrane-bound organelles and a defined nucleus have a single chromosome: a piece of circular, double-stranded DNA located in an area of the cell called the nucleoid nucleoid: the irregularly-shaped region within a prokaryote cell where the genetic material is localized Nucleoid majority of prokaryotic DNA is found in a central region of the cell typically consists of a single large loop called a circular chromosome Cell Wall Extra layer of protection maintain the cell’s shape prevents dehydration Capsule outermost layer of carbohydrates is sticky and helps the cell attach to surfaces in its environment. Flagella are whip-like structures that act as rotary motors to help bacteria move. For locomotion  1 Fimbriae are numerous, hair-like structures that are used for attachment to host cells and other surfaces Pili some types of pili allow a bacterium to transfer DNA molecules to other bacteria, while others are involved in bacterial locomotion—helping the bacterium move. Inclusions Cell inclusions are considered various nutrients or pigments that can be found within the cell, but do not have activity like other organelles.