Medical Interventions Unit 1.1 Study Guide

Outbreaks, Epidemiology, BLAST, ELISA Assay, Serial Dilutions, and Micropipettes

What is an outbreak

A spread of a disease in an area that is not expected

What is epidemiology

The study of disease and outbreaks and other patterns

What is contact tracing

Finding how disease spread in the past and using that to find who will be infected next and break the chain of transmission

What are the ways a pathogen is transmitted

Coughing, sneezing, bug/animal bites, contaminated foods/objects, close contact

What information would you want to collect from a person who may have been exposed to an infectious disease

Exposure timing, the natural of contact, and a personal health background check

What is Patient Zero

The first person to spread a disease or to get infected

Why might it be difficult or impossible to determine who the actual Patient Zero was

Not everyone person infected shows symptoms, the incubation period might cause confusion, and it can be hard to remember every interaction

What does BLAST stand for

Basic Logical Alignment Search Tool

What is the purpose of using BLAST to analyze an unknown DNA sequence

To compare the unknown DNA sample to known biological sequences to find similarity

What does an E-value tell you about a BLAST match

The number of different alignments with a score equal to or better than an observed match that you expect to find by chance in a database of a given size (smaller is better)

If an unknown DNA sample has a 99% sequence identity with a known organism, what does this suggest about the unknown sample

The unknown sample belongs to the species or is a very close relative within the same genus

What does ELISA stand for

Enzyme-linked immunosorbent assay

What is the purpose of an ELISA assay

to detect and measure specific antibodies, antigens, proteins, and hormones in body fluid samples like blood, urine, or saliva

What is an antigen

A substance or molecule that triggers a immune response in the body

What is an antibody

Proteins produced by the immune system to find and neutralize foreign invaders like bacteria

How do antibodies recognize antigens

by locking onto specific target sites on foreign invaders using a precise chemical and structural fit

What is the purpose of the enzyme attached to an antibody in an ELISA

to make the conversion of a colorless substrate into a detectable signal

What happens when the enzyme’s substrate is added

A color change happens

What does a color change indicate in an ELISA

The presence of a specific antigen or antibody in the sample

What does a positive ELISA result mean

The test detected the target antibodies or antigens

What does a negative ELISA result mean

The test did not detect them

Why are positive and negative controls important in an ELISA

ELISA can make mistakes, and the controls are indicators that results are inaccurate if they fail

What would it mean if the positive control did NOT produce the expected result

The test is invalid

What is serial dilution

the method of lowering the concentration of a substance in a solution by repeating the same dilution factor over and over

Why would a scientist use serial dilutions

To reduce a highly concentrated substance into a more manageable level

If you mix 1mL of a sample with a 9mL of water, what is the dilution factor

1/10

If you perform a 1:10 dilution and then dilute that sample 1:10 again, what is the overall dilution

1/100

What happens to the concentration of a substance as you continue making serial dilutions

It decreases exponentially

What units are commonly used when measuring small volumes with a micropipette

microliters (𝝁𝐋)

What is the purpose of selecting the correct micropipette for a specific volume

For an accurate measurement or precision

Why should you never set a micropipette outside of its recommended volume range

It might not get the correct volume, and can lead to inaccurate results. It can also damage the micropipette

What is the difference between the first stop and second stop when using a micropipette

The first stop is to get rid of bubbles, the second stop is to get rid of the solution completely

Why should a new pipette tip be used when transferring between different samples

To avoid cross-contamination