Answer:
DNA replication occurs through the help of several enzymes. These enzymes "unzip" DNA molecules by breaking the hydrogen bonds that hold the two strands together. Each strand then serves as a template for a new complementary strand to be created. Complementary bases attach to one another (A-T and C-G).
Explanation:
Which of the following events occurs directly after RNA polymerase recognizes the transcription start site of a gene? the DNA strand begins to unwind, separating the two strands.
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Answer:
Infectious diseases are diseases caused by living organisms like viruses and bacteria. They can be passed from person to person through body secretions, insects or other means. Examples are SARS, influenza, the common cold, tuberculosis (TB), Hepatitis A and B.
Answer:
Explanation:
An epitope (antigen determinants) is the part of an antigen that interacts with antibodies.
Epitopes bind to antibody molecules via T-cell receptors in a region known as complementarity determining region (CDR) and the Major histocompatibility complex (MHC) participates in this by forming complexes with peptides. The MHC helps the T-cell to recognise epitopes of antigens and discriminate self from non-self.
The MHC, T-cell works together to bring about the binding of epitopes to antibody molecules.
The main function of MHC molecules is to bind to antigens derived from pathogens and display them on the cell surface for recognition by the appropriate T-cells.
It should be noted that the amino acid sequence of the CDR determines the shape of the binding sites of the T-cell and the antibody that can be bound by an epitope.
The consequences of the interactions are;
1. MHC-peptide complex helps T-cell receptors bind to epitopes and thus antibodies
2. The shape of the binding sites (CDR) determines the antibodies that can be attacked any abnormalities at this point will affect the adaptive immune system.
The nurse should advice the patient to avoid intake of fluids before the surgery. This is the most likely intervention technique that would help avoid intra-operative complications, reduce cerebral edema, and prevent postoperative vomiting. The nurse should also prescribe the proper medication to ensure that the patient won't encounter any further problems after the operation.
