Crossing over is important because it creates genetic variability.
<h3>What is crossing over?</h3>
It is the exchange of chromosomal segments between non-homologous chromosomes in a tetrad.
Since chromosomal segments contain genes at different loci, the exchange will increase the genetic variability of the new chromosomes.
Thus, the daughter cells carrying the recombined chromosomes will be genetically variable from not just the parent cell, but fellow daughter cells.
More on crossing over can be found here: brainly.com/question/19671756
#SPJ1
Answer:
The correct answer is-a polysaccharide found in animals
Explanation:
Glycogen is a polysaccharide which is a highly branded form of amylopectin. In glycogen glucose residues are joined together by α1-4 glycosidic linkage and α 1-6 branching points occurs after every 8-10 glucose residues.
Glycogen is the main carbohydrate storage form of carbohydrates in animals. Glycogen is mostly present in liver and muscles. It breaks down into glucose and provide energy to the animal during the physical activity. Therefore glycogen is polysaccharide found in animals.
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.
