Summary

An enzyme-linked immunosorbent assay (ELISA) is typically performed to detect the presence and/or amount of a target protein of interest within an experimental sample. Detection of the target protein is made possible by antibodies, which make the ELISA an immunoassay. Through a series of incubation and washing steps, these antibodies, which are frequently linked, or conjugated, to an enzyme, will detect protein coating the bottom of a well on a microtiter plate. When exposed to a substrate, antibody-bound enzyme will cause a color change, thereby indicating the presence of the protein-of-interest in the sample.

In this video, the theory behind how ELISAs work is explained, including a discussion of both primary and secondary antibody binding and the importance of blocking steps. Theory is followed by practice, as the video progresses to an explanation of the step-by-step procedure. Finally, variations of the standard ELISA such as the sandwich and competitive ELISAs are introduced, and real world applications of this method, such as in over-the-counter pregnancy tests are explained.

1. For which of the following applications could an ELISA be used?

- To neutralize trypsin within a sample.

- To determine the size of a plasmid within a sample.

- To determine the presence or absence of contamination within a sample.

- To determine the presence or absence of a specific protein within a sample.

2. The target protein is recognized by...

- ...the substrate.

- ...buffer enzymes.

-...unlabeled viral particles.

-...the primary antibody.

3. The absorbance measured for each well is _____to the amount of target protein present in

each sample. (cell culture media harvested from human anti-body- producing cell lines).

- equal

- not directly related

- inversely proportional

- directly proportional

When gluconeogenesis is activated during fasting in liver, glycolysis slows. How does this happen?

a. pyruvate kinase and pyruvate dehydrogenase are both inhibited by phosphorylation in response to a decreased insulin/glucagon ratio

b. PFK-2 is phosphorylated

c. acetyl CoA allosterically inhibits pyruvate dehydrogenase

d. acetyl CoA allosterically activates pyruvate carboxylase

e. all of the above

1. The novel corona virus that causes Covid 19 has given scientists and especially virologists a great new challenge. Describe the biology of this virus in detail. Then go on to explain fully what you think the first research goal should be and why.

1. Draw and label (or generate in excel) the standard growth curve for bacteria. Explain each of the stages of this curve fully. Conclude by explaining how and why this curve might look if it represented the growth of a lactose degrading bacteria in media that contains both glucose and lactose.

59. Your biology class is performing an osmosis experiment. You are given three identical stalks of celery and three salt solutions of varying concentrations, described below.

Salt Amount of the Solution       

Solution A has more salt than the cells of the celery stalk      

Solution B has less salt than the cells of the celery stalk      

Solution C has the same salt content as the cells of the celery stalk   

a). Identify which solution is isotonic, hypertonic, or hypotonic to the celery stalk cells

b). Describe why the celery stalk will shrink when placed in the hypertonic solution

Mention two equations for determination of GFR value.

1. Describe and/or draw in detail the gram positive and the gram negative bacterial envelope. Then go on to describe all the steps of a gram stain. Conclude by explaining why the gram stain is such an important technique in the microbiology lab.

7. Individual C has a mutation in the proopiomelanocortin gene (POMC), resulting in the lack of functional alpha-melanocyte stimulating hormone (alpha-MSH).

a) How might this mutation impact binding at the MC4 receptor?

b) Phenotypically, is individual C likely to be underweight, normal weight, or overweight? Why?

1. What are the three mechanisms of horizontal gene transfer? Describe each of the three in detail. Then go on to describe the implications of horizontal gene transfer to microbial evolution and 2. human health.

Evaluate the statements below, and select those that correctly apply to the process of high throughput genome sequencing. Check All That Apply In the 4th step, the sequenced fragments are aligned, and the entire genome is computed using bioinformatics software. In the 4th step, the sequenced fragments are aligned, and the entire genome is computed using bioinformatics software. In the third step, the amplified fragments are read and sequenced based on the Sanger method. In the third step, the amplified fragments are read and sequenced based on the Sanger method. In the second step, the fragments bind to static probes and are amplified by PCR. In the second step, the fragments bind to static probes and are amplified by PCR. In the third step, gaps between contigs must be resolved to obtain the entire sequence. In the third step, gaps between contigs must be resolved to obtain the entire sequence. In the second step, each of the DNA fragments is engineered into a plasmid, and the plasmid is inserted into an E. coli cell to produce a library. In the second step, each of the DNA fragments is engineered into a plasmid, and the plasmid is inserted into an E. coli cell to produce a library. In the first step, the DNA is fragmented and fitted with short DNA sequences designed to match probes in the second step.

During a bioremediation process, nitrates and phosphates are added to soil contaminated with petroleum oil. Explain why chemicals such as nitrates and phosphates are added to the soil instead of adding additional bacteria.

As the scientific director of a pharmaceutical company, you are interested in developing a drug that would prevent the cataplectic attacks experienced by narcoleptic humans. Based on the series of scientific research articles published about narcolepsy using dogs, rodents, and humans, how should your target drug function?

How do CAM plants avoid oxygenation and photorespiration? How do C4 plants avoid oxygenation and photorespiration?