chapter1_cell

Revealing Specific Proteins in Living Cells
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green fluorescent protein (GFP)
• Determining the Intracellular Concentration of Ca2+ • fura-2
2.3. Phase-Contrast and Interference Microscope
Stage
Condenser control knob Base
Samples preparation
• Samples for Light Microscopy Usually Are:
•Fixed, Sectioned, and Stained
2.2 Fluorescence Microscopy
• Fluorescence Microscopy Can Localize and Quantify Specific Molecules in Cells • A chemical is said to be fluorescent if it absorbs light at one wavelength (the excitation wavelength) and emits light (fluoresces) at a specific and longer wavelength.
chapter 1. The Dynamic Cell
The first cells on earth crossed over the threshold of life whey gained abilities to grow, metabolize, and reproduce. the early cells accumulated organic compounds from their liquid environment and used them for energy and raw materials.
• Visualize Unstained Living Cells
• Detailed views of transparent, live, unstained cells and tissues are obtainable with phasecontrast microscope and interference microscopy.
Preparation of Fixed, Stained Samples for TEM
• the fixed sections must be much thinner for electron microscopy (only 50-100 nm, about 0.2 percent of the thickness of a single cell). • Heavy metals, such as gold or osmium,
• The modern, detailed understanding of cell architecture is based on several types of microscope.
The development of magnifying lenses:
1.Light Microscope :
In the seventeenth century, the Dutch lens maker Anton van Leeuwenhoek invented the first single lens light microscope. 1668, red blood cell circle in rabbit ear and frog foot; 1674, describe blood cell 1675, protist 1677, animal sperm 1683, bacterium
2.4.2 Scanning Electron Microscope
3. The Cell Theory：
• 1838 Matthias Schleiden , a German lawyer-turned-botanist ; A year later the German Anatomist Theodor Schwann
1.The study of Cell
observation • to study life and its processes involved simple observation. This approach is still quite useful
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2. Microscope and Cell Architecture
Revolution comparison:
Transmission electron microscopes is:
→→1000 times greater→→ light microscopes
→→500,000 times greater →→ the naked eyes
2.4.1 transmission electron microscope (TEM)
Different parts of a microscope Revolving nosepiece Objective Eyepiece Body tube Coarse adjustment Fine adjustment Arm
Clip
Condenser
Iris diaphragm
Mirror
Plant cells
Relatively larger in size Regular shape Cell wall present Large central vacuole Starch granules as food store Nucleus near cell wall
Part 1. Cell biology
2.4. Electron Microscopy
The human eye has a resolving power of 100μm. The best light microscopes have a resolving power of 0.2 micrometers(μm). the electrons microscope can resolve objects separated by a distance of only 2 angstroms (A)(0.0002μm).
• Cell Structure and Function
• Cell Cycle, Division
Why you need to study the cell?
• “Long ago it became evident that the key to every biological problem must finally be sought in the cell for very living organism is, or at sometime has been, a cell.” • Edmund B. Wilson • From:The Cell in Development and Heredity • 3rd edition, 1925, M animals are composed of cells.
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The CELL THEORY, or cell doctrine, states that all organisms are composed of similar units of organization, called cells. The concept was formally articulated in 1839 by Schleiden & Schwann and has remained as the foundation of modern biology. 1.The cell is the unit of structure, physiology, and organization in living things. 2.The cell retains a dual existence as a distinct entity and a building block in the construction of organisms. 3.Cells form by free-cell formation, similar to the formation of crystals (spontaneous generation). We know today that the first two tenets are correct, but the third is clearly wrong. The correct interpretation of cell formation by division was finally promoted by others and formally enunciated in Rudolph Virchow's powerful dictum, "Omnis cellula e cellula"... "All cells only arise from pre-existing cells". The modern tenets of the Cell Theory include: 1. All known living things are made up of cells. 2. The cell is structural & functional unit of all living things. 3. All cells come from pre-existing cells by division. (Spontaneous Generation does not occur). 4. Cells contain hereditary information, which is passed from cell to cell during cell division. 5. All cells are basically the same in chemical composition. 6. All energy flow (metabolism & biochemistry) of life occurs within cells.