Lab terms Flashcards
What is data?
Information. No shit. :P
What is replication?
Reproducibility is the ability of an entire experiment or study to be reproduced, either by the researcher or by someone else working independently
What is a (working)model?
When the data support the hypothesis in multiple experiments, the hyoithesis can be a working model.
What is a scientific theory?
A model with substantial evidence from multiple investigators supporting it becomes a scientific method.
What is variability?
Human variability, or human variation, is the range of possible values for any measurable characteristic, physical or mental, of human beings. Differences can be trivial or important, transient or permanent, voluntary or involuntary, congenital or acquired, genetic or environmental.
How does a crossover study work?
In a crossover study each individual acts both as experimental subject and as control. Thus, each individuals respoonse to the treatment can be compared to his or her own control value. This method is particularly useful when their is a wide variability within a population.
What is a placebo?
An inactive drug
What is the placebo effect?
Sometimes patients given a placebo treatment will have a perceived or actual improvement in a medical condition, a phenomenon commonly called the placebo effect.
What is a nocebo effect?
A harmless substance that creates harmful effects in a patient who takes it. The nocebo effect is the negative reaction experienced by a patient who receives a placebo
What is a blind study?
To control nocebo and placebo effects patients are not told wether they are given the treatment or the placebo. This may have a bias as reasearchers observing the study may have expectations which may color the result.
How does the double blind study work?
In the double blind study neither the participants or reasearchers know whether the participants are given the treatment or placebo. instead only a third party knows.
what is a double blind crossover study?
In this type of study the control group in the first half of the experiment becomes the experimental group in the second half and vise versa. here no one involved kn ows who is taking the inactive drug.
List the different types of data and tell how each one is unique.
- Bar graphs are used when yhr indipendent variables are distinct individuals.
- Histograms are a specialized bar graph that shows the distribution of one variable over a range.
- Line graphs are appropriate when the variable on the X axis is continuous
- Scatter plots show the relationship between two variables
What are longitudinal studies?
Designed to be carried out over a long period of time
What are cross sectional studies?
These studies survey a population for the prevalance of a disease or condition.
What is Meta analysis?
Meta analysis combines all the data from a group of similar studies and uses statistical techniques to extract significant trends or findings from the combined data.
What is the difference between a positive and negative control?
A negative control group is a control group that is not exposed to the experimental treatment or to any other treatment that is expected to have an effect. A positive control group is a control group that is not exposed to the experimental treatment but that is exposed to some other treatment that is known to produce the expected effect. These sorts of controls are particularly useful for validating the experimental procedure.
What solutiuons are used to test for the presence of sugar, lipids, protein and
- Benedict’s test for simple sugars:
Benedict’s reagent contains blue copper (II) sulfate (CuSO4) which is reduced to red copper (I)
oxide (Cu2O). The copper oxide is insoluble in water and precipitates out of solution. The color of
the final solution may appear green to brick red depending on how many of the copper (II) ions
are present. - Lugol’s Iodine (IKI) test for the presence of starch:
Iodine dissolved in an aqueous solution of potassium iodide - reacts with starch producing a deep
blue-black color. This reaction is the result of the formation of polyiodide chains from the reaction
of starch and iodine. The amylose, or straight chain portion of starch, causes the dark blue/black
color. The amylopectin, or branched portion of starch, causes the formation of an orange/yellow hue. When starch is broken down or hydrolyzed into smaller carbohydrate units, the blue black color is not produced. The iodine solution will also react with glycogen and cellulose, although the color
produced is more brown and much less intense. - The Sudan IV test for the presence of lipids: Sudan IV (C24H20N4O) is a red, fat-soluble dye used for staining lipids, triglycerides and lipoproteins.
Staining is an important chemical technique, offering the ability to visually qualify the presence of the fatty compound of interest without isolating it. - The Biuret test for the presence of proteins: Biuret reagent, made of sodium hydroxide and copper (II) sulfate, is used for determining the presence of protein in a sample. The test relies on the reaction between copper ions and peptide bonds in an alkaline solution. A violet color indicates the presence of protein.
