Answer:
Having considered how an appropriate primary immune response is mounted to pathogens in both the peripheral lymphoid system and the mucosa-associated lymphoid tissues, we now turn to immunological memory, which is a feature of both compartments. Perhaps the most important consequence of an adaptive immune response is the establishment of a state of immunological memory. Immunological memory is the ability of the immune system to respond more rapidly and effectively to pathogens that have been encountered previously, and reflects the preexistence of a clonally expanded population of antigen-specific lymphocytes. Memory responses, which are called secondary, tertiary, and so on, depending on the number of exposures to antigen, also differ qualitatively from primary responses. This is particularly clear in the case of the antibody response, where the characteristics of antibodies produced in secondary and subsequent responses are distinct from those produced in the primary response to the same antigen. Memory T-cell responses have been harder to study, but can also be distinguished from the responses of naive or effector T cells. The principal focus of this section will be the altered character of memory responses, although we will also discuss emerging explanations of how immunological memory persists after exposure to antigen. A long-standing debate about whether specific memory is maintained by distinct populations of long-lived memory cells that can persist without residual antigen, or by lymphocytes that are under perpetual stimulation by residual antigen, appears to have been settled in favor of the former hypothesis.
Because the lung has two bronchi, it can still function if one bronchus is blocked by a foreign object. No gas exchange will happen to the affected side, and the other lung will compensate for the loss of air. The blocked portion though can become inflamed and can lead to infection and damage.
I think it’s BY x BY that would be able to make all three.
Answer:
Explanation:
<u>a. How many chromosomes does a child receive from its father?</u>
Every person receives half of their chromosomes from their father and half from their mother. For that reason, if humans have 46 chromosomes in each somatic cell, 23 of them come from the father.
<u> b. How many autosomes and how many sex chromosomes are present in each somatic cell? </u>
Each somatic cell has 46 chromosomes in total; of which 22 pairs are autosomes and 1 pair are sex chromosomes. Therefore, 44 chromosomes are autosomes and 2 chromosomes are sex chromosomes (the X and/or Y chromosomes).
<u>c. How many chromosomes are present in a human ovum? </u>
The human gametes (ovum in women and sperm cell in men) have half of a somatic cell's genetic material, so that when they combine in a zygote to create their child, they form an initial cell with 46 chromosomes in total. The ovum therefore has 23 chromosomes: 22 autosomes and 1 sex chromosome.
<u>d. How many sex chromosomes are present in a human ovum?</u>
As I mentioned in the previous question, a human ovum has 1 sex chromosome. That way, when it combines with a sperm cell, which also has 1 sex chromosome, they form a zygote with <u>a pair</u> of sex chromosomes (one that comes from the mother and one from the father).
