Why is it necessary to use a young culture 24-hr old culture in gram staining?
less than 24 hours old. Older cultures tend to lose the
ability to retain stains.
Due to a a variety of betalain pigments the red colour of beet root is generated.The composition of different betalain pigments can vary, giving breeds of beetroot which are yellow or other colors in addition to the familiar deep red.
Why must all wet mount preparations be cut very thin?
Cutting the wet mount preparation very thin ensures that light can pass through the specimen easily, allowing for better visualization under the microscope. Thicker specimens may result in distortion or difficulty in observing fine details.
Can you remove air bubbles from a microscope slide by gently warming the slide?
No, warming the slide will not remove air bubbles. To remove air bubbles from a microscope slide, gently tap or press the cover slip down to allow the bubbles to escape. This can be done by applying slight pressure to the edges of the cover slip with a small tool like a needle or a cover glass forceps.
How does an electron microscope create an image if it will not use light and lenses?
the electrons are used to use to create an image apposed to the light because the beam of electrons has a smaller wavelength than light. This results in electron microscopes having a higher resolving power tham optical (light microscopes) Instead of lenses, the elctron microscopes use magnetic condensors to focus the beam. An image is generated by the electrons hitting a electrosensetive board connected to a computer. Each electron that lands on the board causes a voltage accross the board. The computer then generates an image from many voltages produced by the electrons
What are the advantages of an electron microscope over a light microscope - 46k?
Electron microscopes have much higher resolution compared to light microscopes, allowing for better visualization of smaller structures. Electron microscopes can also distinguish finer details due to the shorter wavelength of electrons. Additionally, electron microscopes can observe samples in greater depth by creating 3D images through techniques like tomography.
A staining rack is a laboratory tool used to hold and organize slides during the staining process. It typically has grooves or slots where slides can be securely placed to prevent them from moving or touching each other while applying different staining solutions. Staining racks help in efficient and uniform staining of multiple slides at once.
What is the difference between a light microscope and an electric microscope?
A light microscope uses visible light to produce an image of a specimen and is used for viewing cells, tissues, and small organisms. An electron microscope, on the other hand, uses a beam of electrons to produce a much higher resolution image and is used for studying structures at the cellular and molecular level.
Which microscope do not use a beam of light?
An electron microscope does not use a beam of light. Instead, it uses a beam of electrons to visualize specimens at much higher resolution than can be achieved with light microscopes.
Moves body or stage up and down for focusing?
This movement is called "bobbing" and it helps to visually focus the image by moving the stage or body of the microscope closer to or farther away from the objective lens. It allows you to bring the specimen into sharp focus by adjusting the distance between the objective lens and the specimen.
State how an electron microscope differs from a light microscope?
An electron microscope bombards its target with electrons, while a traditional microscope uses visible light. Electrons can be resolved at considerably higher magnifications that visible light (due to their smaller wavelength).
Which microscope uses light to magnify and has only one lens?
A simple microscope uses light to magnify and has only one lens. These microscopes are commonly used in schools for educational purposes and have a lower magnification power compared to compound microscopes.
How do you store a microscope?
When storing a microscope, first clean it thoroughly to remove any debris or oils. Next, cover it with a dust cover or place it in its storage case. Store it in a cool, dry place away from direct sunlight and fluctuations in temperature. It's also a good idea to remove any batteries to prevent corrosion.
What precautions are important when a prepared slide is observed under the microscope?
Microscopes work on the principle of magnifying light rays passing through a tiny object. The object should be transparent or translucent and colored to be properly viewed under a compound microscope. Some of the mandatory requirements to prepare a good slide for viewing are as follows:
Before creating a smear, always check that the slide is clean and perfectly transparent. It should also be microbe free. So, take a slide and wash it first with soap-water, and then wipe it with ethanol (ethyl alcohol). This makes the slide clean and sterilized.
With regard to preparing a slide of bacterial specimen, when you create a smear, do not make a thick layer of smear. Take very little quantity of the inoculum. If by chance you take too much of the inoculum, spread it over the slide to a larger area, such as to avoid a thick smear.
Air drying is necessary, as it lets the bacteria congregate at their places. Heat fix the slide with precision. Too much heat fix can kill the organism, and too little of it will make the organisms too loosely bound to the slide surface. If they are loosely bound, they will fall off when you flood the slide with stain. One good way of identifying the extent of heat fix is to feel it after you pass the slide through the flame. It should neither be too hot nor warm. It should give you the sense of heat but tolerable.
When you stain the slide, do not stain the whole surface of the slide. This wastes much of the stain and is messy. Cleanliness is very important in all science experiments. Just staining the area containing the smear is enough. Usually, stainings are done for a minute or two, but for certain experiments like endospore staining, the extent of staining time may be as long as 10 mins or even more. During such cases, ensure that the stain does not dry over the smear. Maintain liquidity of the stain, as it is to be washed after some time.
While washing the slide after staining, do not let the water stream fall directly on the smear. This may disrupt the smear. Let the stream of water flow slowly along the surface, such that only the stain is flooded and the smear is intact.
While preparing fungal slides, take the stain first, and then the hyphal fragments. Crush the hyphal fragments properly by placing a coverslip over the fragments (avoiding air bubbles) and the slowly tapping it with the butt of a pencil.
Always observe under 10X first. This will give you an idea of the location of a good area for observation. After this, you may prefer to switch over to 45X.
100X objective in compound microscopes is always used as an oil-immersion objective, so do not ever observe at a specimen at 100X without oil.
What does the electron microscope do?
An electron microscope uses a beam of electrons to illuminate a specimen, providing higher resolution images than a light microscope. It can magnify structures up to 2 million times, allowing for detailed examination of small objects at the molecular and atomic levels.
Ways in the proper handling of laboratory apparatus?
There are many types of lab apparatus and safety precautions differ greatly for the different types. Here are some general rules.
* Always wear proper eye safety gear in the lab. Safety goggles should cover the eyes completely. Regular glasses cannot be used instead of safety goggles.
* You should have a separate container for broken glass. Never throw away glass in a regular trashcan where it can cut open the bag and cause an injury.
* For fast moving equipment like centrifuges, make sure that all parts are secure and balanced before operating.
* Be careful when handling mercury thermometers. Learn how to take care of mercury spills in the lab you are in. Most labs have a mercury spill kit in the building if not in the lab.
* Watch out for bottles of solvents (such as dichloromethane) that have a top designed to let you squeeze the solvent conveniently for cleaning purposes or heavy use. After use these often build up pressure due to low vaporization temperatures and can squirt their contents after being set down towards you, another person, or your reaction.
* When dealing with open flame be sure to know about the fire safety guidelines of your lab. Also, be sure to clear the area of any flammable objects including bottles of flammable solvents.
* Try not to work alone in the lab. It is always better to have a safety buddy who is familiar with a lab setting and knows the proper safety guidelines.
* When dealing with apparatus that either creates a vacuum or exerts pressure be sure to make sure everything is in working order and remember that such apparatus have the potential to explode.
What is an advantage to being able to rotate the body tube on a microscope?
Rotating the body tube on a microscope allows for easy sharing of the view between multiple users without having to move the entire microscope. It can also be useful for adjusting the eyepieces to a comfortable position for different users.
On what part of the microscope is the slide placed and how is it placed?
The slide is placed on the stage of the microscope. It is typically secured in place using stage clips or a mechanical stage. The slide should be positioned so that the region of interest is centered over the light source to enable clear viewing.
How do you find the total magnifying power of a microscope?
MP=(d/L)*(1-(L-l)f)
where d would be the distance from the eye to the image without a lens
L is the distance from the eye to the new virtual image (with a lens)
l is the distance from the eye to the lens
this equation only covers a single lens (whereas there tend to be two in a microscope), but that's no worry; use it twice!
(i.e treat both lenses as independent sources of the image)
What are the optical parts of a compound microscope?
The optical parts of a compound microscope include the eyepiece (ocular lens), the objective lens, and the condenser. The eyepiece magnifies the image, the objective lens collects light from the specimen, and the condenser focuses light onto the specimen.
To center the image in the microscope, you would need to move the slide downwards and towards the left. This movement will bring the off-centre image towards the center of the field of view. Remember to adjust the slide carefully to avoid damaging the microscope or the specimen.
Why is the compound microscope so important?
The compound microscope is important because it allows for magnification of small objects that are otherwise invisible to the naked eye. It is essential for various fields such as biology, medicine, and materials science to study cells, bacteria, tissues, and other microscopic structures in detail. The compound microscope has greatly advanced scientific research and discovery by enabling scientists to delve deeper into the world of the extremely small.
What was Anton Van Leewenhoek the first to see in the 1600s?
Anton Van Leeuwenhoek was the first to observe living single-celled organisms, known as microorganisms or bacteria, through his simple microscopes in the 1600s. This discovery revolutionized the field of microscopy and our understanding of the microbial world.
Hematoxylin is only the drastic substance that these solutions contain. For histology, the two most commonly used are Mayer's Hematoxylin and Harris' Hematoxylin. They both contain water, hematoxylin and various salts.
Why you coat the sample with a conductive material in a electron microscope?
Electron microscopes work by reflecting electrons from the sample to build an image. This achieves a higher degree of magnification than conventional microscopy which uses reflected photons (light) to build a magnified image. However, samples which are often viewed under an electron microscope (particularly biological samples) would not reflect the electrons by themselves, but would allow them to pass straight through. Coating the sample with a conductive metal ensures that the electrons are reflected by the coated sample so that a magnified image can be built up