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10 Cards in this Set
- Front
- Back
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What is a cell?
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Smallest structural and functional unit of any living organism.
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First cells were identified by who and when? What is the full story?
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Identified in the middle 1600s by Robert Hooke. He was part of the Royal Society in Lodon; place where science "happened". Rich people with money would join. Hooke was a curator and he did anatomical work. They didn't figure out how things functioned until later. Good with microscopes. Good with glass and polishing glass. They could take polished glass and magnify objects significantly. Their magnification of objects was almost to the resolution of a micrometer.
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Robert Hooke was looking at what material?
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Cork; plant material. Noticed compartments and decided to call them cellulae. Noticed this throughout and shortened name to cells. Decided this was of importance because everything had them. Mid 1800s others looked at and attempted to identify function of cells.
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Cell Theory
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1. All organisms are composed of one or more cells
2. Cell is the basic unit of structure for all organisms 3. All cells arise only from preexisting cells |
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Better microscopes
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Early 1900s microscopes became much better. Sub micron measurements. In 1930s Germans developed the electron microscope, which could go to a nanometer.
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Primary problem studying cells?
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Small. 10-100 micrometers is average size. Organelles are measured in nm.
1 micrometer=1000nm .005micrometer=5nm |
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Why can't cells be bigger?
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O2, CO2, NH2. All required for cellular function. In and out of cell by cellular diffusion. Hemoglobin-physiological transport system throughout body.
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Diffusion depends on?
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On distance and concentration gradient. High to low conc. O2 is higher outside cell and low inside; so move out to in.
Distance has to be small to allow O2 to diffuse through. High SA to V ratio is what you want. Smaller cell has greater SA to V ratio than larger cell. |
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SA to V ratio
(big cells) |
Nerve cells can be 1m in length, but only few microns across. SA to V ratio is high. Intestine cells are square. Some cells have vilie to increase SA:V ratio.
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6 typical elements a cell is composed of
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N-CHOPS
Nitrogen Carbon Hydrogen Oxygen Phosphorus Sulfur 99%. 2 combine to make up 70% of the body, H20. |
