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U U prevent secondary antibodies from binding directly to the membran/plastic c. Unblocked membranes are unable to bind antigens d. Blocking agents aren't required in immunoblotting e. To increase the affinity between an antibody and epitope QUESTION 8 What is one major benefit of an scFv over a full-length IgG? a. Since they are small, scFvs can be produced in E.coli and can be improved by phage display b. Since they lack an FoscFvs better stimulate immune responses c. Since they have an FoscFvs better stimulate immune responses d. scFys are heavily glycosylated e. A single scFy can bind multiple antigens QUESTION 9 What are the benefits of a Western blot over a dot blot (the "basic" immunoblot described first in class}? Select all that apply. a Western blots require fewer steps than dot blots b. Dot blots require SDS-PAGE c. Western blots can reveal the size the epitope d. Dot blots can reveal proteolytic digestion e. Western blots can reveal differences in posttranslational modification QUESTION 10 Why is a standard PCR reaction ('end-point PCR) ineffective for quantifying DNA? a. All PCR reactions double the amount of DNA across all cycles b. SYBR dyes are a required part of any PCR c. Standard PCR is better at quantifying DNA than qPCR d. After enough cycles, all PCRs stop amplifying DNA QUESTION 11 Click Save and Submit to serve and submit. Click Save All Answers to save all answers.

Answer 1

8. scFv stands for single-chain fragment variable. The antibodies are usually composed of Fc and Fab region which the tail and antigen-binding region of an antibody. Fc and Fab together form a bulky molecule of about 150 kDa. Thus, scFv have been developed to overcome the challenges related to the higher molecular weight of the antibodies. scFv is a complete functional unit that is composed of the antigen-binding region. scFv are the genetically engineered antibodies that are expressed in E. coli and they can be developed by using phage library. This scFv can be fused with any of the several marker proteins such as fluorescent tags or enzymes that will help in identifying the transformed E. coli colonies.

The scFv is composed of a light chain and heavy chain of Fab that are connected by a flexible peptide linker. scFv lacks Fc region and is capable of eliciting an immune response.

Antibodies are glycosylated proteins and this glycosylation governs the function of the antibody. scFv are also glycosylated protein.

scFv is developed by phage library such that they specifically interact with a particular antigen i.e., they exhibit high specificity towards an antigen.

9. Benefits of western blots over dot blot

In brief, the sample that has to be probed by the desired antibody is handled separately in western blotting (WB) and dot blot (DB). In WB, the sample is resolved by SDS-PAGE and then transferred to the PVDF membrane before probing by an antibody. Whereas in DB, the samples are spotted as a dot on nitrocellulose membrane thus, here we do not get any idea of the molecular weight of the protein. From DB only the presence of the desired protein can be known.

Moreover, the presence or absence of PTMs can be identified by employing specific antibodies. But, from WB we can identify PTMs such as glycosylation or truncation by observing change in the molecular weight of the desired protein.