Group of microorganisms
• They are between living and non-living things.
• Size: Smaller (20-400 nm)
• No cell walls. Protein coat present instead.
•They have no metabolism and can’t replicate independently.
• A virus is called either ‘DNA virus’ or ‘RNA virus’ depending on whether it contains the nucleic acid DNA or RNA
HIV, Hepatitis A virus, Rhino Virus, Polio Virus, Rabies Virus etc.
• Living organisms
• Larger (1000 nm)
• Composition of cell wall: Peptidoglycan or Lipopolysaccharide
• Mode of nutrition: both autotrophic and heterotrophic.
• Reproduction by binary fission.
Staphylococcus aureus, Vibrio cholerae, Lactobacillus acidophilus, Escherichia coli, C. botulinum etc.
•They are eukaryotic organisms and mainly unicellular.
• Composition of cell wall sometime polysaccharide.
• Mode of nutrition: both autotrophic and heterotrophic.
• Locomotion through different Methods. (Flagella or cilia”,
• Mode of reproduction by sexually or asexually.
Amoeba proteus, Euglena gracilis, Paramecium aurelia, Plasmodium falciparum, Pediastrum boryanum etc.
Editors. (2017, April 28). Kent, M. (2005).
a) Antibiotics are chemicals collected from plants or microorganisms, that kill bacteria. For e.g Penicillin, Cephalosporins, cycloserine, polyene, antifungal, ciprofloxacin, tetracyclines etc. Mostly antibiotics act on bacterial cells in order to kill by inhibiting the events necessary for bacterial growth. Some inhibit DNA replication, some, transcription, some prevent bacteria from making proteins, some prevent the synthesis of cell walls, and so on. Castro, J. (2014, March 19).
Many antibiotics, including penicillin, works by attacking the cell wall of bacteria and stop the production of cell wall. Ciprofloxacin and other similar antibiotics prevent the bacteria from multiplying very effectively. Other antibiotics, including tetracyclines prevent key molecules from binding to selected sites on cell structures called ribosomes, where protein synthesis occurs. Without its proteins, the bacteria can’t carry out vital functions, including asexual reproduction. Rifamycin, inhibit the synthesis of RNA, a molecule involved in translating the body’s DNA into proteins.
b) In our today’s society, more people rely on antibiotics, the more bacteria develop resistance to them, which makes treating infections that much more challenging. According to the U.S. Centers for Disease Control and Prevention (CDC), human beings are misusing antibiotics such as for the mistreatment of viral infections hence, these important drugs are less effective for all of us.
In our modern society taking inappropriate antibiotics increasing the risk of getting an antibiotic-resistant infection later. Antibiotics not only kill bad bacteria, but also kill the body’s good bacteria. This can lead to antibiotics resistance then bacteria survive and continue to multiply causing more harm. Antibiotics kills or inhibit the growth of susceptible bacteria. To avoid the treat of antibiotic-resistant infections, it is important to avoid taking unnecessary antibiotics. Antibiotics Use and Misuse. (n.d.).
A) Tuberculosis (TB) Bacterial disease: TB is caused by an airborne bacterium, Mycobacterium tuberculosis. Infectious droplet nuclei are generated when persons who have pulmonary or laryngeal TB disease cough, sneeze and even speaking can spread the disease quickly from an infected person to another person, especially in areas of social deprivation and overcrowding. Drinking infected unpasteurized cow’s milk also spread TB. Kent, M. (2005).
Most cases of TB are curable using a combination of four antibacterial drugs. If patient is diagnosed with active pulmonary TB and Extrapulmonary TB, then will be prescribed at least a six-month course of a combination of antibiotics. Two antibiotics (isoniazid and rifampicin) for six months and two additional antibiotics (pyrazinamide and ethambutol) for the first two months of the six-month treatment periods. Treatment for patients having latent TB involves either taking a combination of rifampicin and isoniazid for three months, or isoniazid on its own for six months. Treatment. (n.d.).
B) AIDS (acquired immune deficiency syndrome): It is caused by a virus known as HIV (human immunodeficiency virus). These viruses have no cell and much smaller than bacterium. HIV is transmitted mainly by unprotected sexual intercourse (homosexually or heterosexually). The Virus can pass from infected semen or vaginal fluids to the blood of new host through damaged tissue in the rectum, vagina, or penis. It can be also transmitted via infected blood or blood products, from an infected mother to her child, through the thin lining of the mouth and eyes and through cuts and sores in the skin. Causes of HIV AND AIDS. (n.d.).
Although there is no known cure of AIDS, chemotherapy with cocktails of drugs can delay mortality, and there are many ways of slowing the spread of it. Blood products used in transfusions should be heat treated to destroy the virus. Education programmers should inform everyone about the risks of unprotected sex and the sharing of needles. Those who has multiple sex partners should know that wearing condoms reduces the risk of infection considerably. Offer and encourage HIV tests to people at risk to avoid further spreading the disease. Causes of HIV AND AIDS. (n.d.).
C) Malaria, Parasitic disease: It is caused by a single- celled parasite belonging to the genus Plasmodium. It enters the bloodstream through the bite of an infected female Anopheles mosquito. If a mosquito bites a person already infected with malaria, it can also become infected and spread the parasite on to other people. Once they make their way to the liver in human body they multiply. After an incubation period of 12 days to 10 months the parasites return to the bloodstream and invade healthy blood cells, in which they grow and multiply rapidly. In very rare case malaria can be also transmitted through blood transfusion and sharing of needles. Kent, M. (2005).
Malaria control measures includes eradicating the vector. Vector control is the main way to prevent and reduce malaria transmission. If coverage of vector control interventions within a specific area is high enough, then a measure of protection will be conferred across the community. WHO recommends protection for all people at risk of malaria with effective malaria vector control. Two forms of vector control – insecticide-treated mosquito nets and indoor residual spraying – are effective in a wide range of circumstances. Preventing mosquitoes biting people and using drugs to prevents infections. Fact sheet about Malaria. (n.d.).
The immune system is the body system responsible for resisting disease. It has the remarkable capacity to recognize and It has made up of a network of cells, tissues, and organs that work together to protect the body.
Immune responses to antigens may be categorized as primary or secondary responses. The primary immune response occurs when an antigen comes in contact to the immune system for the first time. During this time the immune system must learn to recognize antigen and how to make antibody against it and eventually produce memory lymphocytes.
Whereas, the secondary immune response occurs when the second time (3rd, 4th, etc.) the person is exposed to the same antigen. At this point immunological memory has been established and the immune system can start making antibodies immediately. Kent, M. (2005).
Figure 1. Shows immune response and secretion of antibodies
In primary response antibody producing cells are Naïve B cells and T cells. Figure 1 shows that the Peak Response is smaller. It takes longer time to establish immunity. Antibody levels are at about day 14 and then begin to drop off as the plasma cells begin to die. Lag phase is often longer (4-7 days), sometimes a weeks or months. First antibody produced is mainly IgM. Although small amount of IgG is also produced and no negative phase. Antibody level declines rapidly. (fig1.)
In Secondary phase antibody producing cells are memory B cells. Above figure 1 shows that there is larger peak response. Due to the many more memory cells than in T and B cells for the primary response, more plasma cells are generated in the secondary response, and antibody levels are consequently higher. Lag phase is shorter (1-4 days) due to the presence of memory cell and Level of antibody reaches peak in 3 to 5 days. It takes shorter time to establish immunity. Mainly IgG antibody is produced, and Antibody level remain high for longer period. Differences between Primary and Secondary Immune Response. (2019, February 26).
In active natural we acquired immunity by contracting an infectious disease by normal means whereas in active artificial we receive vaccination, then our body produces antibodies as part of our normal immune response.
In passive natural, antibodies passed from the mother to the baby before birth transfers passive immunity to the baby for the first 4-6 months of life or via colostrum during breastfeeding. But in passive artificial when high levels of antibodies specific to a pathogen or toxin (obtained from humans, horses, or other animals) are transferred to non-immune persons through blood. For e.g Tetanus injection
B lymphocytes (B cells) are produced in the bone marrow. It helps by ensuring antibody production get antigen and presenting antigens to T cells and providing signals for T cells activation. T lymphocytes (T cells) are produced in the bone marrow but mature in the thymus. It plays vital role in signaling for growth and activation of B cells, activation of cells that can eat foregin substances, stimulation of cytotoxic T cells during a viral infection and signaling growth in cells, including other T cells, macrophages and eosinophils.
A B cells with the complementary receptor to an antigen ‘locks onto’ the pathogen which divides (mitosis) to form clones (plasma cells). Some plasma cells clone into cells that produce specific antibodies to that antigen. Other clones form memory B cells. These cells last a long time in the body. They are ready to produce antibodies in the future if the same pathogen re-infects the body. A macrophage that has engulfed a pathogen presents the pathogen’s antigens on its cell surface membrane, called antigen presenting cell (APC). A T cells with a complementary receptor divides to form clones of clonal selection, all able to recognise that specific pathogen’s antigen. Some of these T cells clones develop into T killer cells that kill any human cell infected with that specific pathogen.
Some of these T cells clones develop in to T helper cells that secrete cytokines that stimulates more phagocytes to engulf human cells infected by that specific pathogen, stimulate B cells to produce antibodies specific to that antigen, stimulates T cells to destroy infected human cells.
Both T killer and T helper cells produce their own memory cells that can respond to future infections of that specific pathogen. There’s no point producing more B cells, T cells or macrophages forever. So, T suppressor cells inhibit the production of more B cells, T cells and macrophages specific to that antigen.
Vaccines are responsible for many global public health successes, such as the eradication of smallpox and significant reductions in other serious infections like polio and measles. Ideally, vaccinations for highly contagious such as measles should be administrated to many people at the same time. This provides a general immunity in the population called herd immunity.
But, based on surrounding issues vaccinations are not equally effective on all people. In fact, some people may not respond at all, perhaps because they have inherited a defective immune system. Herd immunity offers them some protection because it reduces the risk of encountering the infectious agent. Some diseases are difficult to vaccinate.
Therefore, vaccines are responsible for many global public health successes all over the world, but they have also long been the subject of various controversies.
a) Karyotyping can be done from blood, hair, or any other tissue. However, most karyotyping for medical diagnostic purposes is done on embryonic or fetal cells from unborn babies still in the uterus. The cells are usually collected by one of two methods: amniocentesis or chorionic villi sampling. Doctors use a long needle to remove a small sample of your baby’s cells from the chorionic villi, which are tissues that are found within the placenta.
Clinical cytogeneticists analyze human karyotypes to detect gross genetic changes-anomalies involving more of DNA. Karyotypes can reveal changes in chromosome number associated with aneuploid conditions, such as trisomy 21 (Down syndrome). Karyotype Test: Purpose, Procedure, Results. (n.d.).
b) Carrier tests is used to analysis of a person’s genes to see if they are carrier of recessive diseases such as cystic fibrosis. This type of testing is offered to individuals who have a family history of a genetic disorder and to people in certain ethnic groups with an increased risk of specific genetic conditions. If both parents are tested, the test can provide information about a couple’s risk of having a child with a genetic condition. Women’s Health Care Physicians. (n.d.).
Figure 2 showing how genetic modification is used to produce insulin in bacteria.
Above figure 2 showing the process used to produce insulin from genetically modified bacteria. A plasmid, a small piece of circular DNA is taken out from the bacteria or yeast cell then cut out a small section of circular plasmid by restriction enzymes, molecular scissors. The human insulin of the gene is inserted in to the gap in the plasmid which is now genetically modified and introduced into a new bacteria or yeast cell. Then these cells start making insulin by dividing rapidly. The more insulin is produced when the cells divide more.
The genetically modified bacteria or yeast are grown in large fermentation vessels to make large amounts of the cells which contain all the nutrients they need. The mixture is filtered to release the insulin after fermentation is complete. Then insulin is purified and packaged into bottles and insulin pens are ready for the distribution as shown in above fig 1.2.