How is it that vertebrates are able to produce antibodies to virtually every foreign antigen with which they come in contact?
What will be an ideal response?
Human B cells, for example, can make between 106 and 109 different antibody molecules. This is because the millions of immune receptor genes do not exist as a single sequence of nucleotides. Instead, they are assembled by joining three or four DNA segments each coding for different portions of the receptor molecule. When an antibody is assembled, different sequences of DNA are brought together to form a composite gene by a process called somatic rearrangement. Two other processes, collectively known as somatic mutation, contribute to antibody diversity. One occurs as DNA segments are joined with one or two off-register nucleotides, shifting the frame reading during transcription and generating a new sequence of amino acids in the process. The second occurs as random mistakes arise during DNA replication within lymphocytes as they divide during clonal expansion.
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Characterize the structure and function of antigens
What will be an ideal response?
Identify the correct sequence of events for the digestion of starch?a. Salivary amylase is produced by the salivary glandsb. Starch digestion begins in the mouthc. Starch digestion begins in the stomachd. Starch is converted into maltosee. Starch is converted into glycogenf. Maltose is digested into glucose in the small intestineg. Glucose is absorbed in the small intestineh. Glucose is absorbed in the large intestine
A. a - b - e - f - g B. a - c - d - f - h C. a - b - d - f - g D. b - c - a - g - h E. a - c - d - f - g
Researchers are arguing for some sort of "individual transferable quotas". What will those do?
What will be an ideal response?
The cells that surround each stoma and control its opening and closing are
A. sieve tube cells. B. vascular cells. C. companion cells. D. pith cells. E. guard cells.