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irga5000 [103]
3 years ago
6

01:20:01

Biology
2 answers:
harkovskaia [24]3 years ago
7 0

Answer:

The correct Answer is B Madagascar

Explanation:

Just took the test

Free_Kalibri [48]3 years ago
4 0
Helllo u seem very smart
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Which of the following is a chemical reaction? A.breaking a glass pane B.freezing water B.digestion of food C.cutting down a tre
joja [24]
The answers A. C. D. are all physical reactions 

The answer is B. Digestion of food 

When food is digested it is chemically broken down 

Hope this help! 
3 0
3 years ago
Read 2 more answers
In fast-twitch oxidative-glycolytic fibers, their rapid increases in force rely on the ________ activity where rapid relaxation
Kitty [74]

Answer:

1. myosin ATPase

2. Ca2+-ATPase

Explanation:

ATPase activity of myosin head hydrolysis ATP and energize the myosin head. The energized myosin head forms cross bridges to facilitate the power stroke of muscle contraction. The fast-twitch oxidative-glycolytic fibers have the ability to produce ATP by aerobic respiration.  

These fibers have the  ATPase in their myosin heads that hydrolyze ATP three to five times faster than the myosin ATPase in slow fibers. This ensures the faster speed of contraction of these fast-twitch muscle fibers.

During their relaxation, Ca2+ ATPase pumps the calcium ions back to the sarcoplasmic reticulum. As the level of Ca2+ ions in the sarcoplasm decreases, calcium ions are released from troponin. Tropomyosin is allowed to cover the myosin-binding sites on actin and the muscle fiber relaxes faster.

4 0
3 years ago
Explain the interaction that occurs between a t-helper lymphocyte and a b cell when the b cell is being induced to produce peanu
Paraphin [41]

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.  


7 0
3 years ago
How does the presence of starch show that photosynthesis has taken place
Irina18 [472]
Glucose is a product of photosynthesis. Glucose is also a type of starch.
7 0
3 years ago
The phenomenon of fusion is likely to occur when, after a period of geographic isolation, two populations meet?
irinina [24]
The right answer for the question that is being asked and shown above is that: "a decreasing number of viable, fertile hybrids is produced over the course of generations." The phenomenon of fusion is likely to occur when, after a period of geographic isolation, two populations meet is that <span>a decreasing number of viable, fertile hybrids is produced over the course of generations.</span>
6 0
2 years ago
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