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Instrumentation 6

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Microscopy is the study of objects or samples that are too small to be seen by the naked eye. There are several types of microscopy, each with its own advantages and limitations. Here are the main types of microscopy: 1. Optical microscopy: This is the most common type of microscopy, which uses visible light to illuminate a sample. Optical microscopy can be further divided into several subtypes, such as brightfield, darkfield, phase contrast, fluorescence, and confocal microscopy. Optical microscopy is a technique that uses visible light to observe the sample under a microscope. It consists of several components, including an objective lens, an eyepiece lens, and a light source. The working of optical microscopy involves the following steps. The sample to be viewed is prepared by fixing it onto a glass slide and adding a stain or dye to enhance its contrast. The light source, located beneath the sample, emits light that is directed through the condenser lens to focus the light o...
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STD 12th / Ch-8/ Explain elephantiasis and write the symptoms and prevention.

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Elephantiasis , also known as lymphatic filariasis , is a parasitic disease caused by filarial worms , which are transmitted by mosquito bites . The disease affects the lymphatic system , which is responsible for draining excess fluids and waste products from tissues and organs. Elephantiasis is characterized by a swelling of the limbs , genitals , and breasts , which can be disfiguring and disabling. Symptoms of elephantiasis typically develop gradually and may include: Swelling of the arms, legs, genitals, or breasts Thickening of the skin and underlying tissues Pain and discomfort in the affected areas Fever, chills, and other flu-like symptoms in some cases Lymphedema, which is the accumulation of lymphatic fluid in tissues, leading to inflammation, infection, and skin changes. Elephantiasis can also lead to social stigma, depression, and isolation, as people with the disease may be viewed as untouchable or cursed by their communities. Prevention of elephantiasis primarily involv...
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STD 12th / Ch-8/ Malaria

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Malaria is a life-threatening disease caused by the Plasmodium parasite , which is transmitted to humans through the bite of infected female Anopheles mosquitoes. There are several species of Plasmodium, but the most common types that cause malaria in humans are Plasmodium falciparum and Plasmodium vivax . Once inside the body, the Plasmodium parasite multiplies in the liver and then infects red blood cells, causing them to burst and releasing more parasites into the bloodstream. The disease can cause a range of symptoms, including fever, chills, headache, muscle aches, and fatigue. In severe cases, malaria can cause organ failure, seizures, and even death. Malaria is most common in tropical and subtropical regions, including sub-Saharan Africa, Southeast Asia, and South America. The risk of malaria is highest in areas where Anopheles mosquitoes are present and where there is a high rate of Plasmodium infection. Malaria is spread through the bite of infected female Anopheles mosquitoe...
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STD 12th / Ch-8/ What are the various public health measures, which you would suggest as safeguarded against infectious diseases?

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There are several public health measures that can help safeguard against infectious diseases, including: Vaccinations: Vaccines are a safe and effective way to prevent the spread of infectious diseases. Immunizing a population can help prevent outbreaks and can also reduce the severity of an outbreak if one occurs. Personal hygiene: Good personal hygiene, such as regular hand washing and covering coughs and sneezes, can help reduce the spread of infectious diseases. Safe food and water: Safe food and water practices, such as washing hands before handling food, cooking food thoroughly, and avoiding drinking untreated water, can help prevent the spread of foodborne illnesses and waterborne diseases. Quarantine and isolation: Quarantine and isolation measures can help prevent the spread of infectious diseases. Quarantine involves separating and restricting the movement of individuals who have been exposed to a contagious disease but are not yet sick, while isolation involves separating...
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STD 12th / Ch-8/ Short note on Typhoid disease.[Common Diseases of Human /12th biology]

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Typhoid fever is a bacterial infection caused by the bacterium Salmonella typhi . It is spread through contaminated food and water or through close contact with an infected person. The symptoms of typhoid fever can range from mild to severe and typically appear 1-3 weeks after infection. The symptoms of typhoid fever include: High fever (over 100.4°F or 38°C) Weakness and fatigue Stomach pain and discomfort Loss of appetite Headache Body aches and muscle pain Dry cough Constipation or diarrhea Rash of flat, rose-colored spots Enlarged liver and spleen In severe cases, complications can occur, such as intestinal bleeding or perforation, which can be life-threatening. People with weakened immune systems or chronic medical conditions are at higher risk for severe symptoms and complications. If you suspect you or someone you know has typhoid fever, it's important to seek medical attention as soon as possible. Treatment typically involves antibiotics and supportive care to manage sympto...
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STD 12th / Ch-6/ Protein packaging

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Protein packaging  proteins are complex molecules made up of long chains of amino acids. Protein packaging refers to the process by which these amino acid chains are folded and arranged into their final three-dimensional structure. Protein packaging is a critical step in the production of functional proteins because the final structure of the protein determines its function. The folding and arrangement of the amino acid chains are controlled by a variety of factors, including the sequence of amino acids, the pH, temperature, and the presence of other molecules. The process of protein packaging begins as the amino acid chains are synthesized by the ribosomes in the cell. As the chain grows, it begins to fold and twist into a specific shape . This process is known as the primary structure of the protein . Next, the protein begins to fold into a more complex structure , known as the secondary structure . This process is driven by the interactions between the amino acid chains, ...
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STD 12th/Chapter 6 DNA Replication, Transcription & Translation. (quick revision)

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  what is central dogma? Replication: The self-replication mechanism proposed by Watson and Crick,  later termed semi-conservative replication means the first double-stranded DNA separates into two single strands and build two new DNA strand from the first ds DNA. The original statement is  "It has not escaped our notice that the specific pairing we have postulate immediately suggests a possible copying mechanism for the genetic material" (Watson and crick, 1953).   How replication are accorded? here is a simplified flowchart of DNA replication in prokaryotes: Initiation: Replication begins at the origin of replication (oriC). The DNA double helix is unwound by the (enzyme helicase), creating a replication fork. Single-strand binding proteins (SSBs) stabilize the unwound strands. Elongation: DNA polymerase synthesizes new DNA strands by adding nucleotides in the 5' to 3' direction, using the existing strands as templates. The leading strand is synthesized ...
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quick revision [12th chapter 6/topic The Meselson-Stahl experiment proof]

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  for easy to recall..... The Meselson-Stahl experiment, conducted by Matthew Meselson and Franklin Stahl in 1958, provided strong evidence for the semi-conservative model of DNA replication, which proposed that each strand of the original DNA molecule serves as a template for the synthesis of a new complementary strand.   In their experiment, Meselson and Stahl grew E. coli bacteria in a medium containing a heavy isotope of nitrogen, 15N, for several generations until all the DNA in the bacteria incorporated this heavy isotope. They then transferred the bacteria to a medium containing a lighter isotope of nitrogen, 14N, and took samples of the bacteria at different time points after the transfer.   The DNA from each sample was extracted and centrifuged to separate the DNA molecules based on their density. The heavier 15N DNA settled at the bottom of the centrifuge tube, while the lighter 14N DNA formed a band higher up in the tube.   After one generation...
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PETase enzyme.

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  P lastic-eating bacteria are a type of microorganisms that have the ability to break down and consume plastic materials. These bacteria have the enzymes necessary to degrade plastic polymers, which are long chains of molecules that make up most plastic products. One type of plastic-eating bacteria is  Ideonella sakaiensis , which was discovered in 2016 in a plastic waste dump in Japan. This bacterium produces an enzyme called PETase, which can break down polyethylene terephthalate (PET), a common type of plastic used in water bottles and other products. Other types of plastic-eating bacteria have also been discovered, including species that can degrade polystyrene and polyurethane. While the discovery of these bacteria is promising for reducing plastic pollution, there is still much research to be done to understand how they can be used effectively and safely. It's worth noting that plastic pollution is a complex problem that requires multiple approaches to address, includin...
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STD 12th/ Ch-2/ Flowering plants.

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1. Name the parts of an angiosperm flower in which development of male and female gametophyte place. In an angiosperm flower, the male and female gametophytes develop in different parts of the flower. Male gametophyte ( pollen grains ) develops in the anther , located at the tip of the stamen, the flower's male reproductive organ. Female gametophyte ( embryo sac ) develops in the ovule , which is located in the ovary, the female reproductive organ of the flower. 2. Differentiate between microsporogenesis and megasporogenesis. Which type of cell division occurs during these events? Name the structures formed at the end of these two events? Fig: Microsporogenesis in detail Microsporogenesis and megasporogenesis are two different processes involved in the development of male and female gametophytes in plants.  Here are the differences between the two: Definition: Microsporogenesis refers to the process of formation of microspores or pollen grains in the anthers of a flower, wh...
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Golden rice

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  Golden rice is a genetically modified variety of rice that has been engineered to produce beta-carotene, a precursor to vitamin A. This modification gives the rice a yellow or golden color, hence the name "golden rice." Golden rice aims to address vitamin A deficiency, a significant public health problem in many developing countries, particularly in Southeast Asia and Africa.   Vitamin A is essential for human health, particularly for the proper immune system functioning and vision. However, many people in developing countries, particularly those who rely on rice as a staple food, do not have access to sufficient sources of vitamin A in their diet. This can lead to a range of health problems, including blindness, weakened immune systems, and even death.   Golden rice was developed in the late 1990s by a team of researchers led by Dr. Ingo Potrykus of the Swiss Federal Institute of Technology and Dr. Peter Beyer of the University of Freiburg in Germany. ...
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