Cell Culture Techniques Questions and Answers

Answer: C

Culture removes the cells from their normal signals, neighbours and matrix, and they adapt to the new conditions. Findings are usually confirmed in a more complete system before being relied upon. Culture is a starting point rather than a substitute for the whole animal.

Answer: D

Correct answer: published results may describe the wrong cell type

A faster-growing contaminant can replace a line entirely within a few passages, and the culture goes on looking healthy. Every experiment done afterwards then describes the contaminant while claiming to describe the original, and the literature accumulates conclusions attributed to the wrong tissue - sometimes for decades before anyone checks.

Answer: A

Correct answer: Both A and R are true, and R is the correct explanation of A

Both are true and the reason gives the cause of the requirement. Registers list hundreds of lines known to be misidentified, many of them widely used and many overgrown by HeLa. Short tandem repeat profiling settles a line’s identity cheaply, so journals and funders now require it - a response to a documented problem rather than a general tightening of standards.

Answer: B

Correct answer: better reproduces conditions inside a tissue

Cells in a flat layer sit on plastic, receive nutrients uniformly and have neighbours on one side only. In three dimensions they contact each other and a matrix on all sides, and gradients of oxygen, nutrients and waste develop as they do in tissue. Gene expression, differentiation and drug response all shift accordingly, which is why a compound can behave quite differently in the two systems.

Answer: C

Correct answer: True

An organoid is grown from stem cells or progenitors that self-organise into a structure reproducing several of an organ’s cell types and something of its architecture. It is a simplified model rather than a miniature organ - there is no blood supply and usually no immune or nerve component - but it recapitulates development and function far better than a monolayer.

Answer: D

Replacement is the first of the three principles of humane animal research, alongside reduction and refinement. Cost and speed are real advantages but are not the ethical argument. The three principles are replacement, reduction and refinement.

Answer: A

A contamination held in check rather than eliminated persists undetected and may flare later. Good aseptic technique is a better safeguard than a routine additive. Antibiotics also fail entirely against fungal and mycoplasma contamination.

Answer: B

It is generally discouraged, because it conceals contamination and lapses in technique rather than preventing them. Antibiotics are reserved for particular circumstances such as primary isolation from tissue. Most laboratories culture without them as a matter of routine.

Answer: C

Seven flasks give 28 million, which falls short, so eight are needed. Rounding up rather than to the nearest whole number is the point of a question of this kind. Partial flasks are of no use, so the answer must be a whole number upward.

Answer: D

At around minus 196 degrees Celsius no biological process proceeds at a measurable rate, so a stock can be kept for decades. An ordinary freezer allows slow deterioration to continue. Viability falls measurably over months in an ordinary minus eighty freezer.