Cell Theory- in the 18th century, two scientists came up with the cell theory. Schleiden and Schwen. 3 corollaries of the cell theory:
-all cells are alike in chemical composition
-all cells store and process information in the same way
-all cells arise from other cell through cell division
5 types of different Microscopes
1. Light Microscope- produces 2-D image
Direct descendants of Hooks scope> take two lenses to a light source> used this to magnify images up to 1,000 fold. 2. Confocal Microscope- uses lenses& a light source> produces a 3-D image. 3. Fluorescence Microscope- 2-D or 3-D, allows us to visualize fluorescent dyes. 4. Transmission Electron Microscope- it shoots a bean of electrons through a sample, and it collects whatever passes through. -It can do a million fold magnifications.
2-D images, visualize down to 2nm(nanometers)
5. Scanning Electron Microscope- Functions in a similar function to a transmission electron microscope> 3-D images, 3-20 nm in size. What does it mean to be alive?
All living things are composed of cells.
Cells are the basic unit of life. A small membrane enclosed unit with a concentrated aqueous solution of chemicals. It’s endowed with the ability to copy itself. -Every living thing is composed of a colony of cells that began as a single cell. DNA> (transcription)>RNA> (translation)>Protein
Visualization of Cells
-1665 Robert Hooke (professional lens maker, scientist)
He developed a primitive microscope, used it to observe cork. He sees a series of chambers. Actually what Hooke is seeing, is the cell wall of a dead flower that had been near the cork.
Cells vary in size and shape. Generally the diameter of a cell falls between 0,5mm (micrometers) -30mm. Larger cells: Frog Eggs: 1.5mm
Ostritch Egg: 152mm in diameter
Cells are diverse in their chemical requirements that cells need to stay alive. Ex: Some cells require oxygen for life/ Other Cells’ oxygen is lethal Diet
Some cells need water and handful of chemicals
Other cells require complex diets
Cells vary in in their degree of specialization.
-Bacteria are single celled organisms> they do everything necessary for life. -Nerve cells which only function to transmit nervous signals. Prokaryotes are simple/single cells
Eukaryotes are more complex
Bacteria and Archea
Are defined by the presence of a membrane bound nucleus.
Good Bacteria: Food production(Lacto bacillus-yogurt)
Contain membrane bound organelles
Bad Bacteria: Bacillus Anthracius-Anthrax
Single celled-or multi cellular
3 shapes of Bacteria
1. Cocci> spherical cells
2. Bacilli> rod shaped cells
3. Spirochytes>spiral shaped cells (lime disease, Gonorrhea)
Archea- is similar to bacteria, different plasma membrane found in extreme environments. Eukaryotic Cell Structure
Nucleus- The defining characteristic of eukaryotic cells. It is a membrane bound structure that holds the majority of the DNA for the cell. Nucleolus- A dark staining body in the nucleus.
-Is the site of rRNA production as well as the ribosomes making proteins. Mitochondria- the main site for energy production in the cell -Oxidative phosphorylation occurs here.
-Kidney bean or sausage shaped structure
-It has its own DNA, can perform transcription and translation separately. -Similar in shape and size to a bacterial cell
-Mitochondria originated as free-living bacterial cells> developed a symbiotic relationship. Chloroplast- is common in plant cells and it performs cell photosynthesis. It captures energy from the sun and uses it to make sugar. -Has its own DNA and can perform transcription + translation -Believed to have originated as free-living bacteria
Plasma Membrane- is a two-layered structure that defines the perimeter of the cell. Actively controls what goes in and out. “Bouncer of the Cell” Cell Wall is found in plant cells located just outside of the plasma membrane. It is composed of...
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