Cell Biology and Biotechnology Class 10 Science Notes Maharashtra State Board
Cytology
Earlier, we have studied the cell’s structure, types, and organelles. This is called cell biology/cytology. Besides the above-mentioned points, it includes the study of cell division and many other aspects of the cell. There are revolutionary changes in human health due to cell biology. Research institutes specially dedicated to research on cells are established in Pune and Bengaluru, India. National Center for Cell Science (http://www.nccs.res.in) at Pune and ‘Instem’ (http://www.instem.res.in) at Bengaluru are involved in valuable research. Visit both the websites mentioned above and with the help of your teacher, try to understand the research undergoing in those institutes.
Stem Cells
These are special types of cells present in the body of multicellular organisms. These cells give rise to all other types of cells present in the body of multicellular organisms. Similarly, these cells play an important role in wound healing. We had studied the stem cells of plants in the previous class. Now, we shall study stem cells in animals, particularly in human beings. A new organism is formed from the zygote that is formed by the union of male and female gamete. At the earliest stage of development, the organism is in the form of a mass of cells. All the cells in that mass are almost alike. Those cells are called stem cells.
During further development, these cells form any type of cell, and different types of tissues, and perform different functions in the body. This is the differentiation of stem cells. However, once the tissues are formed, the cells in those tissues, at the most, can form the same types of cells only. This is the case in each part of the body. However, stem cells are present for longer duration in some parts of the body.
Stem cells are present in the umbilical cord by which the fetus is joined to the uterus of the mother. Stem cells are also present in the blastocyst stage of embryonic development. Stem cells are present in the red bone marrow and adipose connective tissue of adult human beings. It has become possible to produce different types of tissues and the degenerated part of any organ with the help of these stem cells.
Stem Cell Preservation
For preservation, stem cell samples are carefully collected from sources like cord blood, red bone marrow, or embryo (blastocyst) and are kept in small, sterile vials. Those vials are kept in liquid nitrogen at -135°C to -190°C.
Stem Cell Research
In biotechnology, stem cell research is a revolutionary event after cloning. This technique has the potential to bring about fundamental changes in medical science. Depending upon the source, stem cells are of two types embryonic stem cells and adult stem cells.
Embryonic Stem Cells
Division of the zygote starts and thereby it is converted into an embryo. Cells of embryos undergo repeated mitotic divisions. Cell differentiation starts from the 14th day of conception. Cells of different organs like osteocytes (bone cells), hepatocytes (liver cells), and neurons are formed due to differentiation. Embryonic cells before differentiation are called embryonic stem cells. 220 different types of cells in the human body are formed from single-type cells i.e. embryonic stem cells. Thus, stem cells are the primary type of undifferentiated cells with self-multiplying ability and they are parent cells of all types of human cells. This property of stem cells is called pluripotency. It has been found that if these stem cells are collected well before the beginning of differentiation on the 14th day i.e. during the 5th – 7th day and cultured with certain biochemical stimuli in the laboratory, as per the stimulus, they can transform themselves into the desired type of cells, thereby tissues and finally into organs.
Adult Stem Cells
Stem cells can be obtained from the body of an adult person too. There are three main sources of stem cells in the body of adult persons. Stem cells can be obtained from red bone marrow, adipose connective tissue, and blood. Besides, stem cells can be obtained from cord blood immediately after birth.
Uses of Stem Cells
- Regenerative Therapy
- Cell Therapy: Stem cells are used to replace dead cells in case of conditions like diabetes, myocardial infarction, Alzheimer’s disease, Parkinson’s disease, etc.
- To produce blood cells required in conditions like anemia, thalassemia, leukemia, etc.
- Organ Transplantation: In case of failure of organs like kidney and liver, those can be produced with the help of stem cells and transplanted.
Organ Transplantation
Various organs in the human body either become less efficient or completely functionless due to various reasons like aging, accidents, infections, disorders, etc. The life of such a person becomes difficult or even fatality may occur under such conditions. However, if a person gets the necessary organ under such conditions, their life can be saved. The availability of donors is an important requirement in organ transplantation. Each person has a pair of kidneys. As the process of excretion can occur with the help of a single kidney, a person can donate another one. Similarly, skin from certain parts of the body can also be donated. Various factors like blood group, diseases, disorders, age, etc. of the donor and recipient need to be paid attention to during transplantation. However, other organs cannot be donated during a lifetime. Organs like the liver, heart, and eyes can be donated after death only. This has led to the emergence of concepts like posthumous (after death) donation of body and organs.
Organ and Body Donation:
Human bodies are disposed of after death as per traditional customs. However, due to progress in science, it has been realized that many organs remain functional for certain periods even after death occurs under specific conditions. Concepts like organ donation and body donation have emerged recently after the realization that such organs can be used to save the lives of other needful persons. A liberal view behind the concept of organ and body donation is that after death, our body should be useful to other needful persons so that their miserable lives would become comfortable. Awareness about these concepts is increasing in our country and people are voluntarily donating their bodies.
Life of many people can be saved by organ and body donation. Blinds can regain vision. Life of many people can be rendered comfortable by the donation of organs like the liver, kidneys, heart, heart valves, skin, etc. Similarly, the body can be made available for research in medical studies. Many government and social organizations are working towards increasing awareness about body donation. Organ donation and transplantation are under the control of ‘The Transplantation Human Organs Act of 1994’ and subsequent amendments of 2009, 2011, and 2014 so that the overall process would be transparent and any person would not be cheated.
Biotechnology
We have studied in the earlier class that biotechnology is bringing about artificial genetic changes and hybridization in organisms for human welfare. Various branches of science like cytology, biochemistry, molecular biology, and genetic engineering are included in biotechnology. There is considerable progress mainly in the fields of agriculture and pharmacy due to biotechnology. New experiments are being performed to improve the agricultural yield. In pharmacy, experiments for the production of antibodies, vitamins, and hormones like insulin have been successful. High-class varieties of crops have been developed through the technique of tissue culture.
Biotechnology includes the following main areas
- Use of various abilities of microbes like yogurt production from milk and alcohol from molasses.
- Use of productivity of the cells. Ex: Production of antibiotics and vaccines, etc. with the help of specific cells.
- Use of bio-molecules like DNA and proteins in human welfare.
- Development of plants, animals, and products of desired quality by gene manipulation. Production of human growth hormone with the help of genetically modified bacteria.
- Use of genetic and non-genetic techniques. Non-genetic biotechnology involves the use of either cells or tissue. Ex. Tissue culture, production of hybrid seeds, etc.
Benefits of Biotechnology
- It has become possible to increase the per-hectare yield irrespective of the limitations of the crop-land area.
- Expenses on disease control have been minimized since the development of resistant varieties.
- Due to the development of fast fruit-setting varieties, yield per annum has been increased.
- The development of stress-resistant varieties that can withstand variable temperatures, water stress, changing fertility of the soil, etc. have become possible.
Development of Biotechnology in India
The government of India established the National Biotechnology Board in 1982. This board was transformed into the Department of Biotechnology under the Ministry of Science and Technology, in 1986. Various institutes in India are working under the control of this department of biotechnology. It includes the National Institute of Immunology, the National Facility for Animal Tissue and Cell Culture, the National Centre for Cell Science, the National Brain Research Centre, Central Institute of Medicinal and Aromatic Plants. There are facilities for higher education and research in these institutes from which thousands of students have pursued Ph.D. degrees and are contributing to the progress of the country in the field of biotechnology.
Commercial Applications of Biotechnology
1. Crop Biotechnology:
Biotechnology is used in the agricultural field to improve yield and variety.
- Hybrid Seeds: Genes of two different crops are recombined to form hybrids of various crops. This is especially useful for fruits.
- Genetically Modified Crops: Crops developed with desired characteristics by integrating foreign genes with their genome are called genetically modified crops.
- High-yielding varieties with resistance to diseases, alkalinity, weeds other stresses like cold and drought.
BT Cotton:
A gene had been isolated from the bacterium Bacillus thuringiensis and integrated with the gene of cotton. Due to this, the toxin which is fatal for bollworms was produced in leaves and bolls of cotton. If a bollworm feeds on leaves, the toxin destroys its alimentary canal and the bollworm dies.
BT Brinjal:
BT Brinjal variety is developed by using the gene isolated from Bacillus thuringiensis. This improved variety of brinjal kills the pest in the same way as the BT cotton does.
Golden Rice:
A gene synthesizing the vitamin A (Beta carotene) has been introduced in this variety of rice. As compared to the normal variety, this variety which was developed in 2005 contains 23 times more amount of beta carotene.
Herbicide Tolerant Plants:
Weeds always affect the growth of the main crop. If herbicides are used to destroy the weeds, it affects the main crop too. Due to this, Herbicide tolerant plant varieties of crops are being developed. Due to this, it has become possible to selectively destroy the weeds.
Biofertilizers:
Due to the use of biofertilizers instead of chemical fertilizers, nitrogen fixation and phosphate solubilization abilities of the plants are improved. Mainly bacteria like Rhizobium, Azotobacter, Nostoc, Anabaena, and plants like Azolla are used as biofertilizers. In the last year, we have studied the tissue culture. Genetic improvement of the plants has become possible due to tissue culture and besides, those characteristics inherited by the next generation.
2. Animal Husbandry
Two main methods artificial insemination and embryo transfer are used in animal husbandry. It helps to improve both, the quantity and quality of animal products.
Ex. Milk, meat, wool, etc. Similarly, animals with more strength have been developed for hard work.
3. Human Health
Diagnosis and treatment of the diseases are two important aspects of the human health management. Biotechnology helps to identify the role of genes, if any, in the disease of a person. Diagnosis of diabetes and heart diseases has become possible even before the onset of symptoms, with the help of biotechnology. Diagnosis of diseases like AIDS and dengue can be done within a few minutes. Hence, treatment can be done at the earliest. Various medicines are used for the treatment of diseases. Ex. The hormone insulin is used in the treatment of diabetes. Earlier, insulin was being collected from the pancreas of horses. However, nowadays, due to biotechnology, insulin can be prepared with the help of bacteria. For this purpose, the human insulin gene has been inserted into the genome of bacteria. Various vaccines and antibiotics are also produced in the same way.
Vaccines and Vaccination:
Vaccine is the ‘antigen’ containing material given to acquire either permanent or temporary immunity against a specific pathogen or disease. Traditionally, vaccines were prepared with the help of pathogens. Completely or partially killed pathogens were used as vaccines. However, due to this, there were chances of contracting the disease in the case of some persons. Hence, as an alternative, scientists tried to artificially produce vaccines with the help of biotechnology. For this purpose, scientists produced the antigen in the laboratory with the help of a gene isolated from the pathogen and used it as a vaccine. Thus, safer vaccines are being produced. Now, proteins that act as antigens are injected in pure form instead of injecting the killed or semi-killed pathogens. These proteins keep the person away from diseases by keeping the immune system active. Thus, injecting the antigens is the safest way to vaccination. Vaccines produced with the help of biotechnology are more thermo-stable and remain active for longer duration. Ex. Vaccines for polio, hepatitis,
Edible Vaccines:
Work on the production of edible vaccines is in progress and presently, potatoes are being produced with the help of biotechnology. These potatoes are called transgenic potatoes. These potatoes will act against bacteria like Vibrio cholerae, and Escherichia coli. Consumption of these raw potatoes generates immunity against cholera and the disease caused due to E. coli. What will happen if these potatoes are cooked for consumption?
Treatment:
Biotechnology is useful for the production of hormones like insulin, somatotropin, and blood clotting factors.
Interferon:
This is a group of small-sized protein molecules used in the treatment of viral diseases. These are produced in the blood. However, nowadays, with the help of biotechnology, transgenic E. coli are used for the production of interferon.
Gene Therapy:
Gene therapy to treat genetic disorders in somatic cells has become possible due to biotechnology.
Ex. Phenylketonuria (PKT) arises due to genetic changes in hepatocytes (liver cells). It has become possible to treat it with gene therapy. This method is called somatic cell gene therapy. All the cells except sperm and ova in the body are called somatic cells
Cloning:
Production of a replica of any cell or organ or entire organism is called cloning.
- Reproductive Cloning: A clone can be produced by the fusion of a nucleus of a somatic cell with the enucleated ovum of anybody. Thus, there is no need for sperm to produce the new organism.
- Therapeutic Cloning: Stem cells can be derived from the cell formed in the laboratory by the union of the somatic cell nucleus with the enucleated egg cell. Various diseases can be treated with the help of these stem cells.
- Similar to cells, genes can also be cloned and millions of copies of the same gene can be produced. Those can be used for gene therapy and other purposes.
- Controlling the inheritance of hereditary diseases, a continuation of generations, and enhancing specific tendencies may become possible due to the cloning technique. However, there is worldwide opposition to human cloning on various issues.
4. Industrial Products/White Biotechnology
Various industrial chemicals can be produced through less expensive processes.
Example: Alcohol production from sugar molasses with the help of transgenic yeast.
5. Environment and Biotechnology
It has become possible to solve various problems with the help of biotechnology. Microbial techniques are already in use for the treatment of sewage and solid waste. Sewage is rich in organic matter. If such sewage is released in natural water bodies like rivers, the organic matter in it gets oxidized with the help of dissolved oxygen. Due to this, the level of dissolved oxygen in water decreases, adversely affecting the aquatic life. As a remedy for this, sewage should be released into rivers only after oxidation with the help of microbial techniques.
- Microbes are useful on a large scale in the production of compost by treatment of solid organic waste material.
- Bio-remediation, biopesticides, biofertilizers, biosensors, etc, are some new concepts in biotechnological methods.
Bioremediation means either absorption or destruction of toxic chemicals and harmful pollutants with the help of plants and microorganisms. If plants are used for this purpose, it is called ‘phytoremediation’. Some examples of bioremediation are as follows:
- The Pseudomonas bacteria are useful for cleaning the hydrocarbon and oil pollutants from soil and water.
- The fern Pteris vitata can absorb the arsenic from the soil.
- Genetically modified variety of Indian mustard can absorb selenium from soil.
- Sunflower can absorb uranium and arsenic.
- The bacterium Deinococcus radiodurans is a highly radiation-resistant organism. It has been genetically modified and used to absorb the radiation from radioactive debris.
- Grasses like alfalfa, clover, and rye are used in phytoremediation.
5. Food Biotechnology:
Food items like bread, cheese, wine, beer, yogurt, and vinegar are produced with the help of microorganisms. These food items are probably the oldest ones produced with the help of biotechnology.
6. DNA Fingerprinting:
The DNA sequence of each person is as unique as that of the fingerprints. Due to this, the identity of any person can be established with the help of available DNA. This is called DNA fingerprinting. It is mainly useful in forensic sciences. The identity of the criminal can be established with the help of any part of its body found at the site of the crime. Similarly, the identity of the father of any child can be established. This research is performed in the Center for DNA fingerprinting and Diagnostics, Hyderabad.
Cleaning of Oil Spillage in Oceans:
If oil spillage occurs, it adversely affects the marine life. Now, cleaning the ocean without any harm to the environment in a cheaper way has become possible with the help of oil-digesting and fast-multiplying bacteria. India-born American citizen and scientist Dr. Anand Mohan Chakravarti had for the first time suggested the use of such microbes. Naturally, the credit for this discovery goes to him.
Important Stages in Agricultural Development
Green Revolution
Problems of population explosion started to appear at the beginning of the 20th century. Almost all the countries, especially underdeveloped and developing countries had been badly affected by the effects of poor quality and quantity of food. Various methods applied for harvesting maximum yield from minimum land are collectively called as green revolution. Improvised dwarf varieties of wheat and rice, proper use of fertilizers and pesticides and water management have led to the increased production of food grains and thereby large population has been saved from hunger. Dr. Norman Borlaug (USA) and Dr. M. S. Swaminathan (India) have valuable contributions to a green revolution.
Various research institutes and laboratories are engaged in the development of new varieties of various crops through research.
Ex. Indian Agricultural Research Institute (IARI), New Delhi, National Citrus Research Institute, Nagpur and allied branches, Indian Institute of Sciences, National Pomegranate Research Institute, Solapur.
White Revolution
Various parts of India were rich in milk and milk products. However, those products were not sufficient to meet the needs of far-flung regions. Dr. Verghese Kurien proved through the cooperative movement and use of biotechnology that Dairy cannot be allied but it will be a mainstream business. He put the cooperative dairy movement of Anand, Gujarat at an all-time high status.
While achieving the self-sufficiency in dairy business, various experiments were performed for quality control, newer dairy products, and their preservation. Why do people from all over the world prefer the local wild varieties?
Blue Revolution
Production of various useful aquatic organisms with the help of water is called as blue revolution. Farm ponds and the fishes are very common in East Asian countries. However, people are not only thinking of cultivating the fish and shrimps but other aquatic plants and animals too. The government of India has vowed to increase production by encouraging the people for pisciculture by launching the program ‘Nil-Kranti Mission-2016’ (NKM-16). 50% to 100% subsidies are offered in this case. Marine and freshwater fishery is possible on a large scale. Freshwater fishes like rohu, and catla and other fishery products like shrimp and lobsters are being cultured on large-scale
Fertilizers
Two types of fertilizers are used in agriculture. One of those is organic manure and others are chemical fertilizers. Water holding capacity of the soil improves with soil conservation due to the use of manures. The upper layer of the soil essential in agriculture is formed due to humus formation. Various essential elements like N, P, and K can be available to crops due to earthworms and fungi. In soil-less farming i.e. hydroponics, liquid chemical fertilizers are used. However, there are more harmful effects of the liberal use of chemical fertilizers. It includes a decrease in the fertility of the soil.
Insecticides
Though the natural immunity of plants can prevent infections, the use of insecticides is not under control. Irrespective of the natural friends of farmers like frogs and insectivorous birds, pesticides are used on a large scale to increase yield. Pesticides are a type of poison. This poison enters the food web through water and food and its bio-magnification occurs. Various pesticides like DDT, malathion, chlorpyrifos, etc. have been proven to be dangerous.
Organic Farming
Nowadays, organic farming and organic products have become buzzwords. Organic products are becoming available and demand for them is ever-increasing. Chemical fertilizers and pesticides have been used on a large scale. These poisonous chemicals reached the human body through food and water and their adverse harmful effects on humans and the environment became apparent.
Various problems like soil fertility and pest infestation have become serious. To overcome these problems, farmers are opting for organic farming. It includes a complete ban on chemical fertilizers and pesticides and the use of local, sturdy varieties thereby maintaining natural balance. This is a welcome decision.
Apiculture
You must have seen the bee hive. The worst method of harvesting/collecting the honey from these hives is driving away the bees by smoking the hive with a burning torch and then cutting the hive into pieces. This method destroys the hive and large-scale death of bees. However, it is easy to collect the honey without destroying the hive and bees, if artificial bee boxes are used.
Cultivation of Medicinal Plants
India has been gifted with a great biodiversity. Indian citizens have established a humble and strong relationship with nature. We have a great tradition of Ayurveda that cures diseases with the help of natural sources. In earlier days, medicinal plants were collected from the forest. However, due to depletion in forest areas, medicinal plants are becoming rare. Hence, medicinal plants are being cultivated.
Fruit Processing
We are daily using various products prepared from fruits. All are consuming products like chocolates, juices, jams and jellies. All these products can be produced by processing fruits. Fruits are perishable agro-produce. It needs to the processed in such a way that it can be used throughout the year. Fruit processing includes various methods ranging from storage in cold storage to drying, salting, air-tight packing, preparing murabba, evaporating, etc.
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