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74 Cards in this Set
- Front
- Back
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Microscopes
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-magnify objects
- main benefit is resolution, which gives the ability to see fine detail -can be simple; magnifying glass, water, compound (has more than one lens) |
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Zaccharias and Hans Janssen (holland)
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- Produced a crude microscope
- 1595 - used a two lens system |
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Galileo (Italy)
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-1609
- built a crude compound microscope |
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Anton Van Leeuwenhoek (holland)
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-1600s
- built a simple, single lens microscope - first person to see unicellular movement |
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Robert Hooke (England)
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-1665
- built a compound microscope - 3 lens system |
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Hillier and Prebus (U of T Canada)
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-1930s
- built the first electron microscope |
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First scanning electron microscope
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1940s
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Compound Research Microscope
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-image is produced by light passing through the specimen
- has one eyepiece (ocular) - up to 4 lenses -used to look at transparent specimens -most common microscope -magnifies up to 1000x |
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Dissecting Microscope
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-has two eyepieces
-has two light sources - can be used to look at solid objects - magnifies up to 85x |
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Advantages & Disadvantages of microscopes
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Advantages:
- images are produced in color - are 3D - living material can be used Disadvantages: - low magnifications -poor resolution at high magnifications |
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Transmitted Light
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Light passing through a specimen
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Incident Light
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Light reflecting off a specimen
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Par focal
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When the microscope is focused on one power it should still be in focus when switching to another power
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Inverted Image
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The microscope shows it upside down and backwards
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Virtual Image
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The image as the same as it really is
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Field of View
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-The diameter of what you see
-measured in microns - 1000u = 1mm -field of view decreases as magnification increases |
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Unknown field of view
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Unknown field of view = known field of view
Unknown mag/ known mag |
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Estimation of actual size
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Actual size=field diameter/ fit number
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Scale
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Scale= actual size/ drawing size
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Magnification
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- the number of times a microscope enlarges a specimen
- the number of times bigger a diagram is when compared to the specimens actual size |
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Magnification (formula)
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Drawing magnification= drawing size/ estimated size
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Magnification in Microscopes
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Magnification= ocular lens x objective lens
- 10x multiplied by 4x = 40x -10x multiplied by 10x = 100x - 10x multiplied by 40x =400x |
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Electron Microscopes
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- too large and complex for school use
- use a beam of electrons instead of light - focus by adjusting electromagnets - no color images since color requires light - able to see in great detail - images are called micrographs |
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Transmission Electron Microscope (TEM)
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- a beam of electrons passes through stained tissue embedded in the plastic
- Advantages: ~ very high magnification (100000 to 1500000x), high resolution and the internal detail of a cell can be seen - Disadvantages: ~ 2D, black and white, the specimens must be dead |
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Scanning Electron Microscope
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-scans the surface of the specimen
- image is produced by the reflection of electrons off the surface onto a screen which can be manipulates for 3D view - often coats the specimen with gold for a sharper image - advantages: ~ high magnification (300000x), 3D, black and white image of the surface of the specimen -Disadvantages: ~ the specimen must be dead although recently there is a form that uses living material |
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Confocal Laser Scanning Microscope (CLSM)
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- In the 1980s the use of a laser beam and computers made it easier to view living, transparent specimens
- image is of a very thin section with high resolution which is stored in the computer to product a 3D image |
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Imaging and Staining Techniques (contrast and Stain)
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-contrast is essential to see details
- most cells are colorless when light passes directly through them in a bright field microscopy - stains can be attached to different parts of the cell, improving contrast and the image ~ eg) iodine and methylene blue - stain kills the cell |
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Imaging and Staining Techniques (resolution & fluorescent microscopy)
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- resolution is the ability to distinguish two structures that are very close together
-0.2u for a standard light microscope - light microscopes have limited resolution because when light is focused into small diameters the image becomes blurred - fluorescent microscopy is a technique used to localize substances in cells - fluorescent substances are attached to molecules in cells - they then glow in the presence of ultraviolet light |
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Cell Research at the Molecular level
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-can now see the molecular level of cells in great detail
- using Atomic Force Microscope (AFM) and Scanning Tunneling Microscope (STM) |
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Gene Mapping
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-DNA found in the chromosomes directs the activity of the cell
- the Human Genome Project produced a genetic map of humans so that all gene locations are known which allows scientists to manage disease causing abnormalities - can also manipulate genomes of plants to produce plants that are pest and drought resistant |
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Cell Communication
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-cells are open systems (matter and energy move into and out of the cell)
- messenger molecules from one cell travel through the bloodstream and attach to specific receptors on other cells - the receptors then change shape and allow functions to occur |
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The Cell Theory
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- theory of spontaneous generation was widely believed until proven wrong in the 19th century by Louis Pasteur
- the cell was discovered by Robert Hooke while looking at cork under a microscope in 1665 - the cell theory (as proposed by Scheiden and Schwann) states: ~ all living things are made up of cells ~ all life functions take place in cells, making them the smallest unit of life ~ all cells come from pre existing cells (Note: viruses do not fit this category) |
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The Cell
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1. Intake of nutrients
2. Movement 3. Growth 4. Response to stimuli 5. Exchange of nutrients 6. Waste removal 7. Reproduction |
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Nucleus
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The nucleus is made up of the nuclear envelope, the nucleolus and the chromatin. The nucleus contains genes as well. Known as "city hall"
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Nuclear Envelope
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The nuclear envelope is a double membrane that surrounds the nucleus and contains pores.
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Nucleolus
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The nucleolus aids in the production to ribosomes. It has no membrane but contains 1 or more nucleoli.
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Cell Membrane
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- All cells have a cell membrane that is selectively permeable
- can be described with the Fluid Mosaic Model - made up of: ~ Phospolipid Bilayer; where the phosphates attract water and face out and the lipids repel water and face in ~ Protien channels; found throughout the bilayer and may be attached to the layer or pass all the way through - Phosopholipids and protein move laterally and cholesterol is found packed between the phosopholipids |
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Cytoplasm
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The cytoplasm is a jelly like substance that holds nutrients and organelles in a cell.
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Cytoskeleton
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The cytoskeleton assists the cell in retaining its shape and the functions of a cells movement.
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Mitochondria
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The mitochondria is where the cell is provided with ATP (energy). Known as the "power plant"
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Ribosome
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The ribosomes are small organelles where proteins are produced. Known as bakeries, carpenters or tailors.
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Golgi Apparatus
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The Golgi apparatus is a disk shaped organelle that stores materials and produces carbohydrates. Known as the oil sands plants.
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Lysosomes
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Also known as the "suicide sac", lysosomes are an acidic organelle that is responsible for the digestion of bacteria and damaged organelles.
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Smooth Endoplasmic Reticulum
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The smooth ER is a network of membrane that is associated with the production of fat, oil and steroids
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Rough Endoplasmic Reticulum
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The rough ER is part of the Same membrane as the smooth ER but has different responsibilities, the rough ER is covered with ribosomes and produces protein
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Peroxisomes
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Peroxisomes are organelles that break down fatty acids and detoxify drugs and alcohol.
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Centrioles
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Are structures found in animal cells that involve the process of cell division.
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Vacuoles & Vesicles
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Vacuoles are storage organelles for nutrients and wastes and vesicles are transportation organelles for nutrients and wastes.
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Central Vacuole
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Central Vacuoles are found in mature plant cells where they have roles ranging from reproduction to growth and development
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Chloroplasts
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Chloroplasts are found in plant cells in packages and their responsibility is to drive the synthesis of organic compounds
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Cell Wall
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The cell wall is external to the cell membrane and helps the cell keep its structure.
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The Chemical Composition Of Cell Structures
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- water is a major compound found in cells
- cell structures are made up of carbon, hydrogen, oxygen and nitrogen - organized nto 4 major organic compounds: lipids, carbohydrates, protein and nucleic acids - trace materials such as zinc, magnesium and iron are found |
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Cell fractionation
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is a process that uses centrifugation to separate organelles
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Prokaryotes
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- Do not have a nucleus or nuclear membrane but rather a nuclear region
-usually very small -eg) bacteria |
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Eukaryotes
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-Have a nucleus and nuclear membrane
-Generally larger than prokaryote cells -eg) plants, animals, fungi, protists |
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Surface area to Volume ratio
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SA/V
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Diffusion
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Molecules move from areas of high concentration to areas of low concentration
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Osmosis
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Osmosis is the diffusion of water across a semi permeable membrane
1. Hypotonic: net movement of water into the cell when concentration of water is greater on the outside 2. Hypertonic: net movement of water is out of the cell when the concentration of water is greater on the inside 3. Isotonic: water moves into and out of a cell at the same rate -In animal cells, losing water causes crenation |
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Active Transport
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Active transport invokes the movement of molecules against the concentration gradient
- it requires two things: ~ Transport Proteins ~ ENERGY - protein pump |
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Ocular Lens
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The eyepiece, 10X magnification
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Arm
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To carry the microscope
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Coarse Focus
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To find object on slide
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Fine Focus
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To focus in detail
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Power Switch
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To power the lamp
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Base
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To Carry and support the microscope
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Lamp
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To illuminate specimen
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Condenser or Diaphragm
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Focus light in a thin line
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Stage
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To hold the slide
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Stage Clips
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To hold slide in place
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Low Power Objective Lens
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4X magnification
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Body Tube
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To hold objective lens
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High Power Objective Lens
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40X magnification
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Medium Power Objective Lens
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10X magnification
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revolving nosepiece or turret
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To switch objective lenses
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