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Chapter 4Exam 1February 28th, 2017
Describe the Cell Theory and the experiment that showed where cells originate.
All organisms are composed of one or more cells, it's the basic structural and functional unit of all living organisms and they come about from cells that already exist. Robert Hooke ( 1600's) used the newly invented microscope, looked at thinly sliced cork from a tree through a microscope. He gave the name cellulae meaning small rooms. Anton Van Leeuwenhoek, shoekeeper, used a single lens microscope and seen "many very little animalcules , very prettily moving". He discovered sperm cells, bacteria. Robert Brown, English botanist noticed a body inside a cell and name it the nucleus. Then German botanist, Matthias Schleiden, know nucleus had something to do with development of the cell. Zoologist, Theodor Schwann expanded schleiden and propose that all animals and plants consists of cells that contain a nucleus and also when a cells forms a larger organism, it has its life of its own.
What are the basic functions of a cell?
Carry out essential processes of life. Include nucleic acids DNA and RNA, which carry information and direct the manufacture of cells. They use chemical and light as energy sources for their actives and can respond to changes in the external environment by altering their hereditary reactions. Duplication and pass their hereditary information as part of cellular reproduction.
When would you use an electron, confocal, or light microscope?
Light microscope: When you use light to illuminate the specimen (the object being viewed) Uses a beam of light, and forms a magnified image of the specimen with glass lenses. Provides higher resolution and magnification.
Electron microscope: Use electron to illuminate the specimen, and forms an image with magnetic fields.
What are cells small? Think of volume to surface ratios
Volume of a cell determines the amount of chemical activity that can take place within it, where surface area determines the amount of substances that can be exchanged between the inside of the cell and the outside environment. If you increase the diameter of a cell it gives a surface area that is insufficient to maintain an adequate nutrient waste change for its entire volume. At that point a cell must stop or growth or it must divide to begin anew with a functional surface area to volume ratio.
Distinguish between the cytosol and the cytoplasm
Cytoplasm: Parts between the plasma membrane and the central region. Contains the organelles, cytosol and the cytoskeleton
Cytosol: Aqueous (water) solution containing ions and various organic molecules.
How are eukaryotic and prokaryotic cells different?
Prokaryotic: Makes up bacteria and archaea. The nucleoid has no boundary membrane separating it from the cytoplasm. Plasma membrane is surrounded by a external layer, the cell wall, which ranges in thickness, 15 to 100 nm. Cell wall protects the cell from physical damage. Its coated with glycocalyx "sugar coating". When its loose it's a slime layer and when its gelatinous and attached more firmly to cells it is a capsule. Helps it to attach to surfaces like prokaryotic, eukaryotic cells or nonliving things like rocks. It's plasma membrane has a molecular system that metabolize food molecules into the chemical energy of ATP.
Eukaryotes: Nucleus is separated by membranes from the surrounding cytoplasm. Protists, fungi, animals and plants. Have a true nucleus and cytoplasmic organelles enclosed within a plasma membrane. The cytosol, energy metabolism and molecular synthesis and performs specialize functions in support and motility. Plasma membrane, carries serval functions through proteins, which some of them form channels through the PM that transport substances in and out of the cell. Other protein acts as receptors, they recognize and bind specific signal molecules in the cellular environment and trigger internal responses. In animals, proteins recognize and adhere to molecules on the surfaces of other cells. In the immune system, other plasma membrane proteins label cells as "self" The nucleus is much more complex than the prokaryotic nucleoid, because it separated from the cytoplasm by the nuclear envelope. Which consists of two lipid bilayer membranes. In the nuclear envelope are many hundreds of nuclear pore complexes. It's formed by many types of proteins, called nucleoporins. It exchanges components between the nucleus and cytoplasm and prevents the transport of