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Molecular Biology Lab Techniques and Genetics Fundamentals
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Molecular Biology Lab Techniques and Genetics Fundamentals
Molecular Biology Lab Techniques and Genetics Fundamentals
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1
Question
Why must a blank be measured prior to measuring your sample in spectrophotometry?
Answer
A blank must be measured prior to measuring your sample to calibrate the spectrophotometer and account for any absorbance caused by the solvent or other components apart from the sample. This ensures accurate measurement of the sample's absorbance.
2
Question
How do you find the dilution factor of the final step compared to the original sample?
Answer
You multiply the dilution factors of all the previous steps to find the overall dilution factor of the final step compared to the original sample.
3
Question
Does spectrophotometry measure concentration or absorbance directly?
Answer
Spectrophotometry measures absorbance directly. Concentration is determined by relating absorbance to concentration using a calibration curve or Beer-Lambert law.
4
Question
What is the unit output of a spectrophotometer?
Answer
The output of a spectrophotometer is Optical Density (OD), which measures the absorbance of light by the sample.
5
Question
What do scientists use to cut DNA into smaller fragments?
Answer
Scientists use restriction enzymes to cut DNA into smaller fragments.
6
Question
What is used to make DNA fluoresce under UV light to visualize bands in gel electrophoresis?
Answer
Ethidium bromide is used to make DNA fluoresce under UV light, allowing visualization of DNA bands on a gel.
7
Question
How do DNA fragments separate on a gel during gel electrophoresis?
Answer
DNA fragments separate on a gel based on their size and charge; smaller fragments migrate faster and farther, while larger fragments migrate slower and less far.
8
Question
Do longer DNA fragments travel a shorter or greater distance down a gel compared to shorter fragments?
Answer
Longer DNA fragments travel a shorter distance down the gel compared to shorter fragments because they migrate more slowly through the gel matrix.
9
Question
What is the overall charge of DNA molecules?
Answer
DNA molecules have an overall negative charge due to their phosphate backbone.
10
Question
Where on the gel do the largest DNA molecules appear and why?
Answer
The largest DNA molecules appear near the top of the gel because they migrate more slowly through the gel matrix.
11
Question
What material is the gel composed of in gel electrophoresis used in this lab?
Answer
The gel is composed of agarose.
12
Question
What is added to DNA samples to visualize their movement during gel electrophoresis?
Answer
Loading Dye is added to visualize DNA moving down the gel.
13
Question
Are people with Type AB blood universal donors? Explain.
Answer
No, people with Type AB blood are universal recipients, not donors. Type O-negative is the universal donor because it lacks antigens that can be recognized as foreign.
14
Question
Which cell type produces antibodies in the immune system?
Answer
B cells produce antibodies.
15
Question
What percentage of genetic information is passed on from parents to their offspring?
Answer
50% of genetic information is passed on from each parent to their offspring.
16
Question
Do humans with AB blood type produce anti-A and anti-B antibodies?
Answer
No, humans with AB blood type do not produce anti-A or anti-B antibodies, which is why they can receive blood from any type.
17
Question
How are dominant and recessive alleles represented in genetic notation?
Answer
Dominant alleles are represented by capital letters, while recessive alleles are represented by lowercase letters.
18
Question
What is a phenotype?
Answer
A phenotype is the physical expression of a gene or the observable traits of an organism.
19
Question
Why is blood type O-negative called the 'universal donor'?
Answer
Because red blood cells of O-negative blood type have no antigens that can be recognized as foreign by the recipient's immune system, making it compatible with most recipients.
20
Question
Do humans with the A antigen produce the anti-A antibody?
Answer
No, humans with the A antigen do not produce the anti-A antibody; producing antibodies against your own antigens would cause immune reactions.
21
Question
If you cannot taste phenylthiocarbamide (PTC) but both your parents can, what is your likely genotype?
Answer
Your likely genotype is tt (unable to taste), while both parents are heterozygous Tt (can taste).
22
Question
When does rhesus incompatibility cause health issues?
Answer
Rhesus incompatibility causes health issues when the maternal and fetal Rhesus statuses are different, potentially leading to immune reactions against the fetus.
23
Question
Do Gram-negative bacteria have a thick or thin peptidoglycan layer in their cell walls?
Answer
Gram-negative bacteria have a thin peptidoglycan layer in their cell walls; Gram-positive bacteria have a thick peptidoglycan layer.
24
Question
What reagent is used as a decolorizer in the Gram staining method?
Answer
70% ethanol is used as the decolorizer in the Gram staining method.
25
Question
If bacteria appear pink after Gram staining, what type are they?
Answer
Bacteria appearing pink after Gram staining are Gram-negative.
26
Question
Is Escherichia coli Gram-positive or Gram-negative?
Answer
Escherichia coli is Gram-negative.
27
Question
When diluting solutions using C1V1 = C2V2, what variable do you solve for when making a lower concentration from a higher stock?
Answer
You solve for V1, the volume of the stock (concentrated) solution needed.
28
Question
Why are sterile pipette tips used in the lab?
Answer
Sterile pipette tips prevent contamination of the sample and ensure sample integrity.
29
Question
When should micropipette tips be changed?
Answer
Micropipette tips should be changed when getting a sample from a new medium to avoid cross-contamination.
30
Question
Are all scientific primary literature sources peer-reviewed?
Answer
No, not all primary literature sources are peer-reviewed; some like preprints or conference proceedings might not be.