[Prelim] Xy Biology Flashcards
POSTULATES OF CELL THEORY:
➢ All living things are made of cells
➢ The cell is the basic structural and functional unit of life
➢ All cells come from pre-existing cells
- An organ is composed of different tissues
- Several organs can be grouped together as an organ
system (digestive system) - An idea of hierarchy of structure developed into:
XAVIAR BICHAT (1771-1802)
- discovered cells while looking at a thin slice of cork.
- He described the cells as tiny boxes or a honeycomb
- He thought that cells only existed in plants and fungi
- He examined a thin slice of cork under the microscope that he built. He was able
to see and observe small compartments of the cork and initially named the compartments cellula because they reminded him of the little rooms in the monastery.
ROBERT HOOKE
- Used a handmade microscope to observe pond scum & discovered single-celled organisms
- He called them “animalcules”
- He also observed blood cells from fish, birds, frogs, dogs, and humans
- Therefore, it was known that cells are found in animals as well as plants
ANTON VAN LEUNWENHOEK
He called them “animalcules”
ANTON VAN LEUNWENHOEK
published his research in 1838, which was based on several years of studying different types of plants under the microscope.
MATTHIAS SCHLEIDEN (PLANTS) (1839)
published his research a year later, based on his study of several slides
of animal cells.
THEODOR SCHWANN (ANIMALS) (1839)
The cell is an autonomous unit (“a citizen”) grouped together to form an organism (“the society”)
Cell
- invented by Zacharias Janssen
- With the help of his father, Hans, they made this microscope by placing several
lenses together and discovered that objects were further enlarged upon viewing.
FIRST COMPOUND MICROSCOPE (1595)
- noted that: “all cells come from pre-existing cells”
- It was believed, however, that this discovery was initially made by Robert Remak,
a Jewish scientist, in 1855, when he tried to prove the idea of cell division by hardening the cell membrane.
REMAK & VIRCHOW (1858)
- contains semi-fluid substance called the cytosol where the different organelles are suspended
- Where the molecules first pass through after entering or before exiting the cell membrane
- Within the cytosol are different substances such as electrolytes (produce electrically conducting solutions), metabolites (produced during metabolism), RNA and synthesized proteins. It is also the site of many physiological processes such as glycolysis (conversion of glucose into another form) and protein and fat synthesis
Cytoplasm
- formed when microtubules eventually arrange themselves during cell division.
- Help in the separation and transfer of the replicated genetic materials in the cells
called chromosomes
Centriole
Control center, where genetic processes take place.
Nucleus
Small, dense structures that help in the assembly of proteins in the cell
Ribosomes
-Produces proteins.
- In pancreas and digestive tract, proteins in the form of enzymes break down food. Without these enzymes, digestion is almost impossible. In most cases, these proteins move to golgi apparatus for modification, packaging and distribution.
ROUGH ENDOPLASMIC RETICULUM
