Answer: Infection occurs when the host is exposed to pathogens. virus uses the cell's metabolism, and replicates itself while destroying the cell or changing the cell's genetic makeup.
Explanation:
- A virus is a miniscule pocket of protein that contains genetic material.
- Viruses pose a considerable challenge to the body’s immune system because they hide inside cells.
- This makes it difficult for antibodies to reach them. Some special immune system cells, called T-lymphocytes, can recognise and kill cells containing viruses, since the surface of infected cells is changed when the virus begins to multiply.
- Many viruses, when released from infected cells, will be effectively knocked out by antibodies that have been produced in response to infection or previous immunisation.
- Antibiotics are useless against viral infections. So antiviral drugs work differently to antibiotics, by interfering with the viral enzymes instead.
Hence virus are the pathogen that use the cell's metabolism. And replicate itself while destroying the cell or changing the cell's genetic makeup. viruses are so simple that they use their host cells to perform their activities for them
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Answer:
According to Dr. Ray Schiling (member of the American Academy of Anti-aging medicine) about 1.5 million people suffer from peanut allergies. The seeds of peanut (<em>Arachis hypogea</em>) contain an array of allergens that can induce the production of IgE specific antibodies predisposed individuals. Ara1 and Ara2 are most common seed storage protein that cause allergy. Other allergen proteins such as Ara3 to Ara 17 have also been identified that cause allergy.
Entry of peanut allergen into body
When peanut allergens enter the body of an individuals it leads to development of different symptoms like itchy skin, tingling sensation, nausea, runny nose and anaphylaxis.
Allergic response
There are two subsets of T-cells Th1 and Th2. Both invoke different response to allergens. Th1 direct a non-allergic response while Th2 direct allergic response ranging from releasing of histamine to anaphylactic response. The presence of IL-12 cytokines direct a Th1 based, nonspecific response.
Mechanism of allergic response (interaction between helper T cell and B cell)
Step 1.
When allergen enter to body they are encountered by B cells. Immunoglobulin receptors on the surface of B cells recognize antigen (Peanut allergens) and get attached, which are then internalized and processed. Within B cells the fragments of antigens combine with HLA class 2 proteins.
Step 2
HLA class 2 with antigen fragments (peanut allergens) then display on the surface of B cells.
Step 3
Receptors on the surface of helper T cells recognizes the complex of HLA class 2 and antigen fragments (peanut allergen) and is activated to produce cytokines, which activate the B cells.
Step 4
B cell is activated by cytokines and begins clonal expansion. Some of the progeny become anti-body producing plasma cells while other become memory B cells.
Genotype. A human being's genome is made up of approximately 3 billion base pairs which make up about 2000 genes. Individuals, however, differ slightly in the sequence of their DNA in some regions. This unique genome identity is the indivudual genotype. Sequence of DNA in a genome can nowadays be determined through sequencing using Next Generation Sequencing machines
Answer:false
Explanation:
Phenotype refers to the actual physical and observable characteristics of a person .
