Biochemical Techniques — MCQs

Q: Which assay is specifically used to test for lipid peroxidation?

Fox assay. ***Fox assay*** - The **Fox assay** specifically measures **ferrous oxidation** in the presence of **xylenol orange**, which is used to detect **lipid hydroperoxides**. - It is a common and sensitive method for directly quantifying **lipid peroxidation** end-products in biological samples. *Ames test* - The Ames test is a biological assay used to assess the **mutagenic potential** of chemical compounds. - It detects whether a given chemical causes **mutations** by observing the reversal of a *Salmonella typhimurium* strain's histidine auxotrophy. *MTT assay* - The **MTT assay** (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) is a colorimetric assay for assessing **cell metabolic activity** and viability. - It measures the activity of **mitochondrial reductase enzymes**, which reduce MTT to a purple formazan product in living cells. *Guthrie test* - The **Guthrie test** is a bacterial inhibition assay used for the **newborn screening** of metabolic disorders, primarily **phenylketonuria (PKU)**. - It detects elevated levels of specific amino acids (like **phenylalanine**) in dried blood spots.

Q: Which of the following methods is commonly used for DNA estimation?

Spectrophotometer. ***Spectrophotometer*** - A spectrophotometer measures the **absorption of light** at specific wavelengths, which is used to quantify the concentration of DNA or RNA in a solution. - **Nucleic acids** absorb UV light strongly at **260 nm**, allowing for their accurate estimation. *Spirometer* - A spirometer is used to **measure lung function**, specifically the volume of air an individual can inhale and exhale. - It is a tool for assessing **respiratory health** and has no role in DNA estimation. *pH meter* - A pH meter is used to measure the **acidity or alkalinity** of a solution, expressed as pH. - It works by measuring the **hydrogen ion concentration** and is unrelated to quantifying DNA. *Sphygmomanometer* - A sphygmomanometer is a medical device used to measure **blood pressure**. - It consists of an inflatable cuff and a manometer and is not involved in biochemical assays like DNA estimation.

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Spectrophotometry and Colorimetry

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Chromatography Techniques

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Electrophoresis and Applications

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Centrifugation and Ultracentrifugation

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Radioisotope Techniques

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Enzyme-Linked Immunosorbent Assay (ELISA)

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Polymerase Chain Reaction (PCR)

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Blotting Techniques: Southern, Northern, Western

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Mass Spectrometry in Biochemistry

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Recombinant DNA Technology

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DNA Sequencing

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Proteomics and Metabolomics

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