I think these days many people have started building interest in biology. We are hearing many biology related words in news. And it has become necessary to have some basic knowledge in this field due to COVID-19.
I am planning to write a book about basics of biology which will help many people to understand basics of biology. I am planning to bring up the book in parts so that I can write about trends in biology. I am planning to write about DNA,RNA and proteins and how cells function and many basic concepts.
Here is the look of my book. Hope you guys like it.
These days we are listening the word “IMMUNITY” many times. You might have seen immunebooster drinks, immunity bread and many such products in advertisements. So, what does this word actually mean? Let me help you to understand the word immunity, its types, how to build immunity, and disorders related to it.
Immune system is a complex organization that recognize and tolerate the self and reject the foreign particles. In simpler words it is a check point, acts like body’s defense against infections.
Many cells and organs work together to build this immune system. Phagocytes, lymphocytes, neutrophils , these names you would have come across in blood report. These are the cells of immune system.
Humans have three kinds of immunity:
Innate immunity : Everyone is born with innate immunity. For example : skin acts like a barrier for germs.
Adaptive immunity: This immunity is developed whenever we contract diseases or vaccinated against some disease. For example: polio vaccine.
Passive immunity: It is borrowed immunity and lasts for shorter duration. For example: Mother contracted by some disease during pregnancy gives immunity to her baby for short period of time.
Body fights against many diseases by producing antibodies. Above mentioned three types work together in fighting diseases.
GUIDE TO IMMUNE SYSTEM:
Antigen recognition: In our body we have HLA present on our cells which acts as ID of self cells. The cells which don’t have HLA are treated as foreign and immune system recognizes it as antigen.
Bone marrow: It is the place where immune cells are manufactured.
Phagocytes: These are part of innate immunity and act by eating foreign particles.
1) Neutrophils: They will respond first to infection by eating bad cells and preventing bacteria infection.
2) Macrophages: They work in eliminating bacterial infection from tissues.
3) Eosinophils: These attack and kill big antigens by attaching to them.
Natural killer cells: They mainly attack abnormal cells like cancer cells. These have a major role during viral infection.
Lymphocytes : T and B are the main lymphocytes are the main cells to build acquired immunity.
These are some of the important players of immune system.
ROLE OF B LYMPHOCYTES:
Each B-cell makes specific antibody whenever they encounter the antigen.
Antibodies are part of large group of chemicals called immunoglobulins.
1) IgM: kills bacteria
2) IgD: helps B cells in starting the immune response
3) IgA: present in tears and saliva, prevent antigen entry
4) IgG: it tags the antigen so that it is recognised by immune cells as antigen
5) IgE: protect against parasites and acts during allergies
ROLE OF T-LYMPHOCYTES:
1) Helper T-cells( TH): These cells stimulate B cells to produce more antibodies. Others attract more T cells or cell-eating phagocytes.
2) Killer T-cells ( TC): These play main role in fighting viruses. These identify specific patterns on the surface of viruses and destroy them.
Diseases related to immune system and why do they occur:
When immune system does not work properly it results in various disorders. Reasons for this may be primary immune deficiency i.e born with weak immune, Hyper active immune system due to allergies, acquired immune deficiency syndrome, and auto immune disorder.
Severe combined immunodeficiency (SCID): Children are in constant danger of infections from bacteria, viruses, and fungi, and the disorder is called “bubble boy disease.” In the 1970s, a boy had to live in a sterile environment inside a plastic bubble. It is primary immune deficiency.
Acquired immune deficiency : Immune system can be weakened by certain medicines, for example. This can happen to people on chemotherapy or other drugs used to treat cancer. It can also happen to people following organ transplants who take medicine to prevent organ rejection. Infections like the flu virus,and measles can weaken the immune system.Immune system can also be weakened by smoking, alcohol, and poor nutrition.
AIDS. HIV, which causes AIDS, is an acquired viral infection that destroys important white blood cells and weakens the immune system. These diseases take advantage of weak immune system.
Hyperactive immune system: For some people the factors in environment may act as allergens like pollens, dust, and food items.Some diseases are caused by overactive response of immune system:
Asthma : In lungs, it can cause coughing, wheezing, and trouble breathing. Asthma can be triggered by common allergens like dust or pollen or by an irritant like tobacco smoke.
Eczema.:An allergen causes an itchy rash known as atopic dermatitis.
Allergic rhinitis: Sneezing, a runny nose, sniffling, and swelling of your nasal passages from indoor allergens like dust and pets or outdoor allergens like pollens or molds.
Autoimmune disorders: In autoimmune diseases, the body attacks normal, healthy tissues and is probably a collection of a person’s genes and something in the environment that triggers genes.
Type 1 diabetes: The immune system attacks the cells in the pancreas that make insulin. Insulin removes sugar from the blood to use as energy.
Rheumatoid arthritis: It causes swelling and deformities of the joints. An auto-antibody called rheumatoid factor is in the blood of some people with rheumatoid arthritis.
Lupus: It attacks body tissues, including the lungs, kidneys, and skin. Many types of auto-antibodies are found in the blood of people with lupus.
Even Graves and Celiac diseases come under auto immune diseases.
HOW TO BUILD IMMUNITY:
Building immunity means building white blood cells. This can be achieved by various methods like-
1) Eat more plant foods: Whole plant foods like fruits, vegetables, nuts, seeds, and legumes are rich in nutrients and antioxidants that may give you an upper hand against harmful pathogens.
2) Eat more healthy fats: By this I mean include olive oil, salmon and chia seeds in your diet.
3) Eat fermented foods: Fermented foods are rich in beneficial bacteria called probiotics. These foods include yogurt, sauerkraut, kimchi, kefir, and natto. These help to identify and target harmful pathogens.
4)Physical exercise: Examples of moderate exercise include walking,steady bicycling, jogging, swimming, and light hiking. Most people should aim for at least 150 minutes of moderate exercise per week.
Hope you guys got a clear idea of immunity.
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As you guys might be reading about vaccination drive for COVID-19, so what are vaccines?
Vaccine is a product that builds person’s immune system to fight back a particular disease. Vaccines are usually administered through needle injections, or through drops or nose sprays.
How are vaccines manufactured?
The whole idea of vaccine is to create antibody against particular disease without any illness. That is making person’s immune system well aware of antigen before-in-hand. So, following are the ways in which antigens can be used as vaccines:
a) Attenuated live virus: In this, virus is weakened and injected into the body. These do not cause disease but build immunity in person’s body.
b) Inactivated virus: A form of vaccine in which it is killed. It raises the antibody.
c)Recombinant: Recombinant vaccines are made using bacterial or yeast cells to manufacture the vaccine. A small piece of DNA is taken from the virus or bacterium against which we want to protect and inserted into the manufacturing cells.
d)Conjugate: A conjugate vaccine is a type of vaccine which combines a weak antigen with a strong antigen as a carrier so that the immune system has a stronger response to the weak antigen.
e)Subunit: These contain only the antigenic parts of the pathogen. These parts are necessary to elicit a protective immune response.
f)Toxoid: Long-lasting immunity against bacterial diseases such as tetanus and diphtheria is induced by a course of toxoid vaccines which cause an immune response against weakened versions of specific bacterial toxins called toxoids.
Why there are multiple doses of vaccines?
There are multiple reasons for it:
1) It is studied that more than one doses build immunity very well.
2) For some vaccines, the immunity built is for shorter time. In that case booster immunity is must.
Infectious disease physician Carlos Malvestutto says, “The first dose primes the immune system while the second dose induces a vigorous immune response…” Essentially, a second dose provides more antibodies (also called immunoglobulins), which are “proteins produced by the immune system” in order to fight against foreign substances (antigens). Traditional vaccines contain either weak or inactivated versions of the pathogen (which can be a virus or bacteria), provoking an immune response, allowing the immune system to effectively deal with the pathogen if it enters the body again. It is often the inactivated vaccines that need multiple doses because they are not as close to the actual pathogen in comparison to vaccines that use weak, live versions of the pathogen.
How Vaccines work
Vaccines work by mimicking the infectious bacteria or viruses that cause disease. Vaccination stimulates the body’s immune system to build up defence against the infectious bacteria or virus without causing the disease. The parts of the infectious organism that the immune system recognizes are foreign to the body and are called antigens. Vaccination exposes the body to these antigens. After vaccination, the immune system is prepared to respond quickly and forcefully when the body encounters the real disease-causing organism.
Through this article I am going to share with you the basics of blood grouping. As you all might be knowing humans have four types of blood grouping i.e A, B, AB, and O. There is also a Rh factor determining positive or negative.
Concept of allelism
Genes are the pillars of our life. The things like how we are and how we behave are totally dependent upon the gene expression. Alleles are the pairs of genes occupying a specific spot called on a chromosome. Allelism refers to any of the several forms of a gene. These genetic variations arise usually through mutation and therefore are responsible for hereditary variations. Typically, there are only two alleles for a gene in a diploid organism. When there is a gene existing in more than two allelic forms this condition is referred to as multiple allelism.
Dominant and recessive phenotype:
The phenotype represents the physical structure of the body. There are two types dominant and recessive. As we can understand from the word dominant means which is leading. Same happens with the dominant allele.For example, if both the parents are tall, there are ample chances of the child being tall. We can know from this example that some traits are inherited. Even blood group is inherited. There will be permutation and combination which leads to child’s blood group.
It is the case when two or more forms of allele are present. In the inheritance of ABO blood group in humans, gene I exists in three allelic forms: IA, IB, and IO. IA and IB are codominant. IO is a recessive allele and does not produce antigen. It should be noted though that even if there are more than two alleles present in the population, the individual comprising the population would possess only two such alleles. Thus, in the case of ABO blood group system, the inheritance of IA and IB alleles results in having a blood type AB.
The ABO system: There are 4 main blood groups defined by the ABO system:
blood group A – has A antigens on the red blood cells with anti-B antibodies in the plasma
blood group B – has B antigens with anti-A antibodies in the plasma
blood group O – has no antigens, but both anti-A and anti-B antibodies in the plasma
blood group AB – has both A and B antigens, but no antibodies
Blood group O is the most common blood group.
How blood group detection is done in labs??
Many reputed industries have come up with chemicals and reagents which help in easy detection of blood group. There will be 3 bottles labelled as Anti-A, Anti-B and Anti-D. Anti-D is used to detect Rh factor i.e, positive or negative. The lab technician prepares a slide with the 3 reagents, each one drop. Later they take the blood sample and put some drops on the reagents and mix the three drops individually with three different sticks. The analysis would be, if the clump formation is seen in Anti-A drop then person is of A blood type, if clumps are seen in Anti-D then it shows positive. So becomes A positive. If the Anti-A and Anti-B doesn’t show clump formation then it is O blood group.
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