Biochemical Techniques and Methods Flashcards

Flow cytometry can be used to:

Answer: Count and sort cells based on fluorescent markers

Flow cytometry passes cells single-file through a laser beam and detects fluorescent signals from labeled antibodies or dyes, allowing rapid analysis and sorting of cell populations.

CRISPR-Cas9 gene editing creates targeted double-strand DNA breaks using which component to guide it to the correct genomic location?

Answer: A single guide RNA (sgRNA) complementary to the target sequence

The single guide RNA (sgRNA) base-pairs with the complementary target DNA sequence, directing the Cas9 nuclease to cut precisely at that location in the genome.

Mass spectrometry in proteomics identifies proteins by measuring:

Answer: The mass-to-charge ratio (m/z) of peptide fragments

Mass spectrometry measures the m/z ratio of ionized peptide fragments with high precision; the resulting mass spectra are matched against protein databases for identification.

In a non-competitive inhibition mechanism, the inhibitor:

Answer: Binds an allosteric site on either free enzyme or ES complex, reducing Vmax without changing Km

A non-competitive inhibitor binds an allosteric site independent of substrate binding, reducing Vmax without affecting Km because substrate binding and inhibitor binding are independent events.

Two-dimensional gel electrophoresis (2D-PAGE) separates proteins first by isoelectric point, then by:

Answer: Molecular weight using SDS-PAGE

2D-PAGE uses isoelectric focusing (IEF) in the first dimension to separate proteins by pI, then SDS-PAGE in the second dimension to separate by molecular weight, giving a two-dimensional protein map.

Which technique measures real-time amplification of DNA during PCR by detecting fluorescent signal proportional to DNA amount?

Answer: Quantitative PCR (qPCR)

Quantitative PCR (qPCR) monitors fluorescent signal (from SYBR Green or TaqMan probes) after each amplification cycle, allowing real-time quantification of starting template DNA or cDNA.