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Showing posts with the label Std 12th

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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RNA Vs DNA

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  Note: Although RNA is usually single-stranded, it can sometimes form temporary double-stranded regions through base pairing within the molecule or with complementary RNA or DNA molecules.
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Structure of Antibody Explain in brief.

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Antibodies , also known as immunoglobulins (Ig), are Y-shaped proteins that are produced by B cells in response to the presence of a foreign substance, known as an antigen . Each antibody molecule is composed of four polypeptide chains, two identical heavy chains, and two identical light chains, which are linked together by disulfide bonds. The basic structure of an antibody molecule consists of two identical antigen-binding fragments (Fab) and a single crystallizable fragment (Fc). The Fab region is located at the tips of the Y-shaped molecule and is responsible for binding to specific antigens. The Fc region is located at the base of the Y and is responsible for the effector functions of the antibody, such as activating complement and binding to Fc receptors on immune cells. Each Fab region contains a variable region and a constant region. The variable region is responsible for binding to the antigen and is highly variable between different antibodies, while the constant region ...
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What Is Immunity?

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Immunity is the ability of an organism to resist or defend itself against harmful microorganisms, viruses, toxins, and other foreign substances . It is a complex biological system that involves many organs, tissues, cells, and molecules, working together to recognize, destroy, and remember specific pathogens. Immunity can be divided into two major types:  Innate immunity and adaptive immunity. Innate immunity is the first line of defense that provides immediate, non-specific protection against a wide range of pathogens. It involves physical barriers, such as the skin and mucous membranes, as well as specialized cells and molecules, such as white blood cells, antimicrobial proteins, and complement proteins. Overall, immunity is essential for the health and survival of organisms, as it helps to prevent and control infections and diseases. Adaptive immunity , on the other hand, is a more specific and complex defense mechanism that develops over time in response to specific pathog...
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Introduction of DNA

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Genomic DNA: This is the most common type of DNA found in cells and is the DNA that makes up our genes. It's a double-stranded, helical molecule made up of four nucleotides: adenine, guanine, cytosine, and thymine. Genomic DNA is organized into chromosomes and contains the instructions necessary to produce all of the proteins and molecules required for the cell to function properly. These instructions are encoded in the sequence of nucleotides along the DNA molecule, with each sequence of three nucleotides (a codon) corresponding to a specific amino acid. Mitochondrial DNA (mtDNA): Mitochondrial DNA is a circular, double-stranded molecule found in the mitochondria of cells. Unlike genomic DNA, mtDNA is inherited only from the mother and is used to generate energy for the cell. It codes for a small number of proteins that are essential for oxidative phosphorylation, the process that generates energy in the mitochondria. Because mtDNA is subject to high levels of oxidative stress, i...
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Mendel's first law of inheritance/ Law of Segregation , Incomplete Dominance

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Mendel's first law of inheritance: The concept of manuals (also known as "vandalization") and the law of segregation are both related to the inheritance of traits in organisms. The law of segregation, also known as Mendel's first law of inheritance, states that during the formation of gametes (sex cells), the alleles (alternative forms of a gene) for a particular trait segregate (separate) from each other so that each gamete receives only one allele. Now, let's understand the concept of manuals. In genetics, a manual refers to a group of genes that are physically close to each other on a chromosome and tend to be inherited together as a unit. This is because during meiosis, the process of cell division that produces gametes, these genes are physically linked and tend to remain together. Therefore, the inheritance of one gene in a Mandal is often associated with the inheritance of other genes in that manual. The concept of manuals is related to the law of segre...
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STD 12th/Ch-Reproduction /Asexual reproduction & sexual reproduction

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Asexual reproduction is a type of reproduction that does not involve the fusion of gametes (sperm and egg) from two individuals. Instead, a single individual can produce offspring that are genetically identical to itself. Asexual reproduction is commonly observed in organisms such as bacteria, fungi, plants, and some animals.   There are several different methods of asexual reproduction, including: Cell division in a unicellular organism. Binary fission: This is a common method of asexual reproduction in bacteria and other single-celled organisms. The cell simply divides in two, producing two genetically identical daughter cells. Budding: This method is used by some animals such as hydra and yeast. A small bulge or bud grows on the parent organism and eventually separates to form a new individual. Binary fission,  Budding Fragmentation: This method is used by some plants and animals. The parent organism breaks into several pieces, and each piece can regenerate into a n...
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Gregor Mendel

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Gregor Mendel was an Austrian monk who is widely regarded as the founder of modern genetics. Mendel conducted a series of experiments on pea plants between 1856 and 1863 to study the inheritance of traits from one generation to the next. These experiments involved crossing different varieties of pea plants and analyzing the patterns of inheritance that emerged. Mendel's most famous experiment involved crossing pea plants with different traits for flower color (purple or white) and observing the inheritance of these traits in the offspring. He performed a series of crosses between plants with different flower colors and found that the inheritance of the trait followed a predictable pattern, which he later referred to as the laws of inheritance. Mendel's experiments involved the following steps: He chose pea plants with clearly defined traits (such as flower color) that could be easily distinguished from one another. He crossed plants with different traits and observed the charac...
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STD 12th /Ch-9/ What is plant breeding?

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Plant breeding is the process of altering the genetic traits of plants through selective breeding techniques to create new and improved plant varieties that are more productive, resilient, and better suited for specific uses. It is a fundamental aspect of agriculture that has been practiced for thousands of years and has resulted in the development of crops that are better adapted to different environmental conditions, pests and diseases, and changing consumer preferences. The primary goal of plant breeding is to produce plants that have desirable traits, such as higher yields, better nutritional quality, resistance to pests and diseases, and improved tolerance to abiotic stress factors such as drought, heat, and cold. To achieve this, plant breeders use a variety of techniques to manipulate the genetic makeup of plants, including crossbreeding, hybridization, mutation breeding, genetic engineering, and genomic selection. Crossbreeding involves mating two different plants with desir...
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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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STD 12th / Ch-16, Radioactive Wastes, Defunct ships and e-wastes, Municipal solid wastes.

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Radioactive Wastes: Radioactive waste refers to any material that contains radioactive isotopes and has no current use or intended purpose. This type of waste is often produced by various industries such as nuclear power plants, research facilities, and hospitals. Radioactive waste can also be generated from natural sources such as uranium mining. There are two main types of radioactive waste: low-level waste and high-level waste. The low-level waste consists of materials that have lower levels of radioactivity, such as protective clothing, tools, and medical equipment. High-level waste, on the other hand, is more radioactive and can include spent nuclear fuel, which is a byproduct of nuclear power generation. The safe disposal of radioactive waste is crucial to protect public health and the environment. The most common method of disposal is through burial in specially designed repositories located deep underground. These repositories are designed to isolate waste from the environment ...
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STD 12th/ Ch-5/ What is point Mutation? Give one example.

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  A point mutation is a type of genetic mutation that involves a change in a single nucleotide, or building block, of DNA. Point mutations can occur spontaneously during DNA replication, or they can be induced by mutagens, such as chemicals or radiation. Point mutations can have various effects on the resulting protein, ranging from no effect at all to a complete loss of protein function.   Substitution mutations are the most common type of point mutation and involve the replacement of one nucleotide with another.  Substitutions can occur in various ways, including:   Silent mutations: These occur when the substitution does not result in a change in the amino acid sequence of the protein. This is because of the degeneracy of the genetic code, where multiple codons can specify the same amino acid.   Missense mutations: These occur when the substitution results in a change in the amino acid sequence of the protein. Depending on the position of the substitution a...
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STD 12th/ Ch-5/ Dominance vs Recessive / Homozygous vs Heterozygous / Monohybrid vs Dihybrid.

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Dominance  vs    Recessive Dominance and recessiveness are two important concepts in genetics that describe the relationship between alleles of a gene and the resulting expression of a particular trait. The main differences between dominance and recessiveness are:   Expression: Dominant alleles are always expressed when present, whereas recessive alleles are only expressed when an individual has two copies of the recessive allele.   Effect on phenotype: Dominant alleles have a visible effect on the phenotype, or observable characteristics of an organism, while recessive alleles are not expressed in the phenotype when they are paired with a dominant allele.   Inheritance: Dominant alleles are inherited in a straightforward manner, while recessive alleles may be hidden or masked in one generation and expressed in the next generation if both parents pass on the recessive allele.   Presence in the population: Dominant alleles are typically more commo...
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Structure of Antibody Explain in brief.

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Antibodies , also known as immunoglobulins (Ig), are Y-shaped proteins that are produced by B cells in response to the presence of a foreign substance, known as an antigen . Each antibody molecule is composed of four polypeptide chains, two identical heavy chains, and two identical light chains, which are linked together by disulfide bonds. The basic structure of an antibody molecule consists of two identical antigen-binding fragments (Fab) and a single crystallizable fragment (Fc). The Fab region is located at the tips of the Y-shaped molecule and is responsible for binding to specific antigens. The Fc region is located at the base of the Y and is responsible for the effector functions of the antibody, such as activating complement and binding to Fc receptors on immune cells. Each Fab region contains a variable region and a constant region. The variable region is responsible for binding to the antigen and is highly variable between different antibodies, while the constant region ...
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Impact studies on the growth of a Chlorella Sp. culture using NaNO3/KNO3 as nitrogen sources.

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  The green algae Chlorella sp pure cultures were developed and optimized in modified BG11 media for 24 days under laboratory conditions such as constant temperature (25±1˚C) and light (1000 µmol s -1 m -2 ) 12hr light and 12hr dark periods. After that, axenic seed cultures (2 ml) were inoculated in two triplicate sets of 250 ml flasks containing 100 ml of modified media ( Table 1&2 ) . Then the experimental flasks were kept in laboratory conditions. During the cultivation culture, cell density (growth), biomass, and nutrient consumption were determined over the cultivation time. Media formulation BG11 is a well-known media for green microalgae cultivation. In this study, BG11 media composition was modified to grow Chlorella sp. The preparation of culture media (Tables 1&2) and the salinity (up to 10ppt). The media was divided into two parts, and each part was supplemented with two nitrate sources in the form of sodium nitrate (NaNO 3 ) (20 mM) and potassium nitrate (...
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STD 12th/Ch-5/ Mention the advantage of selecting pea plant for the experiment by Mendel.

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Gregor Mendel selected pea plants for his experiments because they have several advantages that made them an ideal organism for genetic research. Some of the advantages are: Easy to grow and maintain:  Pea plants are easy to grow and can be cultivated in a small area. They have a short life cycle, and many generations can be produced in a short time. A large number of offspring: Pea plants produce a large number of offspring, which allows for statistical analysis and a more accurate determination of genetic ratios. Self-fertilizing: Pea plants can self-fertilize, which means that they can produce offspring by fertilizing their own flowers. This characteristic makes it easier to control and manipulate genetic traits. Clear-cut traits: Pea plants have several easily identifiable traits that are controlled by single genes, such as seed color, flower color, and plant height. These traits are distinct and show clear-cut differences between the two parental varieties. No environmental...
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