In immunology two types of immune response are described depending on whether there is prior contact with the antigen.
• At this first contact, only lymphocytes with receptors specific to the antigen in question are stimulated and lead to the production of antibodies capable of neutralizing it. The lymphocytes capable of recognizing a specific antigen are very few and the production of antibodies - of low intensity and limited duration - is detectable only after a period of latency of several days. This is called the primary response. The specificity of the resulting seropositivity, however, makes it possible to detect contamination (seroconversion).
• Upon re-contact with an antigen that has already triggered a primary response, specific antibody production is found to increase rapidly after a short latency period. The secretion of IgG then reaches levels much higher than those observed during the primary response, while that of IgM is of the same order. This early and intense response, called secondary response, most often results in the destruction of infectious agents before any clinical sign.
• Many centuries before the discovery of microbes, it was noted that people who developed a contagious disease without death were then specifically immunized against the disease, without being protected against others.
• The ability to react appropriately to an already received stimulus supposes the existence of a memory. The immune memory is based on the existence of memory B and T lymphocytes, resulting from the clonal expansion due to the first contact with the antigen. Their lifespan is significantly higher than that of other lymphocytes and their high reactivity gives its rapid and intense character to the secondary response.
Answer:
The tall parent was heterozygous
Explanation:
If tall height is dominant to short height the only genotype possible for short height is hh, while there are two possible genotypes for tall height, Hh and HH. When HH is crossed with hh all the offspring are Hh, but if Hh is crossed with hh, a quarter of the offspring is HH, a quarter is hh and half is Hh. If the tall pea plants were HH there would only be tall offspring, but because there are some short offspring we know that the tall pea plants must have a genotype of Hh.
The primary products of the light independent reactions (after one turn of the cycle) are:
a) two G3P molecules
b) three ADP
c) two NADP+
However ADP and NADP+ are not really "products". They are regenerated and later used again in the Light-dependent reactions. Each G3P molecule is composed of three carbons.
For the Calvin cycle (Light independent cycle) to continue, 5 out of the 6 carbons provided by the two G3P molecules are used to regenerate ribulose 1, 5 phosphate. Therefore there remains only one carbon for the next turn of the cycle.
One molecule of glucose requires 6 turns of the cycle. Any extra G3P is used to make starch, sucrose and cellulose.
