Biotechnology Mock Interview Questions & Practice

What is transcription, and where does it occur in a eukaryotic cell?

Key points to cover:

• Synthesizing an RNA molecule from a DNA template
• Occurs in the nucleus of a eukaryotic cell
• Catalyzed by RNA polymerase

What is a transcription factor, and what role does it play in gene regulation?

Key points to cover:

• A protein that binds to specific DNA sequences
• Often near a gene's promoter
• Activates or represses transcription

What is Mendel's law of independent assortment, and under what condition does it hold true?

Key points to cover:

• Alleles of different genes assort independently during gamete formation
• Holds true for genes on different chromosomes
• Not for closely linked genes

What is the function of the endoplasmic reticulum, and what is the difference between rough and smooth ER?

Key points to cover:

• A network of membranes involved in protein/lipid synthesis
• Rough ER: studded with ribosomes, protein synthesis/modification
• Smooth ER: lacks ribosomes, lipid synthesis and detoxification

What is binary fission, and how do bacteria typically reproduce?

Key points to cover:

• The primary method of bacterial reproduction
• A single cell divides into two genetically identical daughter cells
• Involves DNA replication followed by cell division

What is an antibody, and what is its basic structure/function?

Key points to cover:

• A protein produced by B cells (plasma cells)
• Specifically recognizes and binds to a particular antigen
• Neutralizes the antigen or marks it for destruction

What is the difference between batch, fed-batch, and continuous fermentation processes?

Key points to cover:

• Batch: single closed cycle, no addition/removal during the run
• Fed-batch: periodic addition of nutrients without removing culture
• Continuous: continuous addition and removal, steady-state conditions

What is the purpose of an impeller in a stirred-tank bioreactor?

Key points to cover:

• Provides mechanical mixing of the culture broth
• Promotes uniform distribution of nutrients, oxygen, and cells
• Helps with heat transfer throughout the vessel

What is filtration, and what is the difference between microfiltration and ultrafiltration in bioprocessing?

Key points to cover:

• Uses a porous membrane to separate particles by size
• Microfiltration: removes larger particles like cells/debris
• Ultrafiltration: removes smaller molecules like proteins

What is the significance of sticky ends versus blunt ends produced by restriction enzymes?

Key points to cover:

• Sticky ends: short single-stranded overhangs that can base-pair
• Facilitating efficient, directional joining
• Blunt ends: no overhang, lower efficiency, no directional specificity

What is the difference between a plasmid vector and a viral vector for gene delivery?

Key points to cover:

• Plasmid: small circular DNA, simpler but often less efficient
• Particularly for eukaryotic/mammalian cells
• Viral vector: uses a modified virus, often much higher efficiency

What happens to DNA after CRISPR-Cas9 creates a double-strand break, and what are the two main repair pathways the cell can use?

Key points to cover:

• The cell's natural DNA repair machinery attempts to fix the break
• NHEJ: error-prone, introduces small insertions/deletions
• HDR: uses a supplied DNA template for a precise edit

What is the difference between a global alignment and a local alignment?

Key points to cover:

• Global alignment: attempts to align the entire length end to end
• Local alignment: identifies the best-matching subregions
• Which may be much shorter than the full sequence length

What is the Protein Data Bank (PDB), and what type of information does it store?

Key points to cover:

• A publicly accessible database storing 3D structural data
• For proteins, nucleic acids, and other macromolecules
• Typically determined via X-ray crystallography, NMR, or cryo-EM

What is statistical significance, and how is it typically assessed in a biological study?

Key points to cover:

• A conclusion that an observed effect is unlikely due to random chance
• Typically assessed using a hypothesis test producing a p-value
• Compared against a predetermined significance threshold