40 Questions
Who is credited with the discovery of the relationship between guanine and cytosine, and adenine and thymine?
Erwin Chargaff
What is the typical range of optical density of extracted DNA at 260nm and 280nm?
1.6 to 2.0
What is the name of the process that separates charged molecules based on varying rates of migration through a solid matrix when subjected to an electric field?
Electrophoresis
What is the primary function of helicase in the transcription process?
Unwinding of double-stranded DNA
Which type of RNA is most abundant in cellular or total RNA?
rRNA
What is the term for the amino acid sequences found in mRNA?
Codons
Which of the following is NOT a true statement about the structure of nucleosomes?
Nucleosomes have a left-handed helix structure
Which of the following is commonly used as a non-radioactive label in molecular biology?
Biotin
What is the minimum number of cycles typically performed in a PCR reaction?
30 cycles
What is the role of the detection standard used in performing ELISA?
To add the standard dilution and samples to each well
What does a 'normal' karyotype refer to?
An individual without any genetic disorders
Which of the following is NOT a component of a PCR reaction mixture?
Fluorescent dye
Which molecular marker is commonly used to determine paternity?
STRs
What is the primary function of quantitative DNA amplification?
To measure DNA amplification
Which of the following techniques is NOT used in karyotyping?
Western Blotting
Which of the following is NOT a component of the loading buffer in SDS-PAGE?
NaOH
What does the HER2 gene encode?
A receptor involved in cell growth
What is true about quantitative PCR (qPCR)?
It measures DNA amplification during each cycle
What is the typical volume of standard dilution or samples added to each well in ELISA?
50uL
Which type of DNA is used in Sequence-Specific Oligonucleotide Probe Hybridization?
Genomic DNA
What is the abbreviation FISH stands for?
Fluorescence In Situ Hybridization
Which imaging technique is commonly used to capture images of chromosomes during karyotyping?
Fluorescence microscopy
What is the category of micronutrients that is excluded?
Proteins
Which cellular process is commonly evaded by cancer cells to allow for continuous growth?
Apoptosis
What is the purpose of adding 0.5mL of lysis buffer to the cells?
To extract nucleic acids
What is the ratio of phenol:chloroform:isoamyl alcohol in the extraction solution?
25:24:1
What is the purpose of centrifuging the sample at high speed for five minutes?
To separate the phases of the extraction solution
What is the correct order of the phases after centrifugation?
Aqueous, Interphase, Organic
What is the ideal temperature for primer annealing during cDNA synthesis?
65 degrees Celsius
What is the expected number of cycles achieved after 2-4 hours of PCR testing?
25-30 cycles
What is the factor that may affect primer hybridization?
Salt concentration
What is the method used to visualize DNA amplification via qPCR?
Fluorometry
What is the primary role of tumor suppressor genes?
To inhibit cell cycle progression and repair damaged DNA
What is the significance of microRNAs in cancer?
They regulate gene expression posttranscriptionally
Which laboratory method is used to detect HER2 amplification in breast cancer?
FISH (Fluorescence in situ hybridization)
Which drug is recommended to reduce tumor progression in a patient with breast cancer who overexpresses the HER2 gene?
Trastuzumab
What is the gene most commonly mutated in human cancers?
p53
What is the protein that is often overexpressed in cancers and acts as a marker for cell proliferation?
Ki-67
Which technique is used to measure gene expression levels in tumors?
PCR (Polymerase Chain Reaction)
What percentage of panel reactive antibody (%PRA) is considered to be highly sensitized?
80%
Study Notes
DNA Structure and Purity
- Erwin Chargaff observed that the quantity of guanine equals the quantity of cytosine, and the quantity of adenine is similar to the amount of thymine.
- The optical density of extracted DNA at 260nm and 280nm is between 1.6 and 2.0.
- Miescher was the first scientist to isolate DNA.
Nucleic Acid Separation and Analysis
- Nucleic acids are separated based on size differences in rate-zonal centrifugation.
- Electrophoresis separates charged molecules based on varying rates of migration through a solid matrix when subjected to an electric field.
- In SDS-PAGE, the loading buffer components do not include NaOH.
RNA and PCR
- rRNA is the most abundant naturally occurring RNA in cellular or total RNA.
- PCR reaction mixture does not include fluorescent dye.
- Primer annealing during cDNA synthesis should be done at 65 degrees Celsius.
- The minimum number of cycles typically performed in a PCR reaction is 30.
- qPCR measures DNA amplification quantitatively during each cycle.
DNA Amplification and Detection
- FISH (Fluorescence in situ hybridization) is used to visualize the hybridized probes under a microscope.
- The lower phase of phase separation is also called the organic phase.
- Fluorometry is used to measure DNA amplification.
- The detection step in FISH is used to visualize the hybridized probes under a microscope.
Genetics and Genomics
- The HER2 gene encodes a tyrosine kinase receptor.
- DNA microarrays are used to detect HER2 amplification in breast cancer.
- Sequence-Specific PCR is used to amplify a panel of alleles.
- STRs are commonly used to determine paternity.
Karyotyping and Molecular Biology
- A "normal" karyotype refers to an individual without any genetic disorders.
- Western Blotting is not used in karyotyping.
- In ELISA, the next step after adding the standard dilution and samples to each well is to incubate at room temperature for 2 hours.
- The HLA genotype is determined by assessing which probes were hybridized.
Pharmacogenomics and Cancer
- Trastuzumab is recommended to reduce tumor progression in a patient with breast cancer who overexpresses the HER2 gene.
- p53 is the most commonly mutated gene in human cancers.
- Ki-67 is a marker for cell proliferation and is often overexpressed in cancers.
- MicroRNAs regulate gene expression posttranscriptionally and play a significant role in cancer.
- Irinotecan is classified as a drug that inhibits topoisomerase I.
Test your knowledge of molecular biology concepts, including nucleotides, DNA structure, and transcription processes.
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