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DSE Biology: Biotechnology (Elective) — Practice Questions & Answers
How genetic engineering, cloning and PCR are used to manipulate DNA and organisms, the production of genetically modified organisms, and the ethical issues these raise.
384 practice questions available for this topic — here are 10 with full answers and explanations.
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Practice questions with answers
1
Multiple choice · Medium
Two steps needed to insert a DNA fragment into a plasmid are:
cut the plasmid open with a restriction enzyme, then seal the fragment in with DNA ligase
translate the plasmid, then transcribe the fragment
denature the plasmid, then respire it
replicate the plasmid, then digest the fragment with protease
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Why Cut the plasmid with a restriction enzyme, then seal the fragment in with DNA ligase.
2
Multiple choice · Hard
The same restriction enzyme is used to cut both the gene and the plasmid so that:
their complementary sticky ends can pair up and be joined
the gene is destroyed before insertion
the plasmid becomes linear permanently
no ligase is needed
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Why Their complementary sticky ends can pair up and be joined.
3
Multiple choice · Easy
A plasmid used to carry a gene into a host cell is acting as a:
vector
ribosome
enzyme substrate
nuclear chromosome
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Why Plasmids act as vectors.
4
Fill in the blank · Easy
A small circular DNA molecule used to carry a gene into a host cell is a
Check answer
Answer:
plasmid
Why Plasmids are common cloning vectors.
5
Fill in the blank · Medium
Enzymes that cut DNA at specific sites to give sticky ends are
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Answer:
restriction
Why Restriction enzymes produce sticky ends.
6
Fill in the blank · Hard
The gene is sealed into the cut plasmid by the enzyme DNA
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Answer:
ligase
Why DNA ligase joins the gene to the plasmid.
7
Multiple choice · Medium
A plasmid carries an antibiotic-resistance gene in addition to the useful gene so that scientists can:
identify which crop cells have taken up the DNA fragment by their antibiotic resistance
make the crop respire faster
destroy untransformed cells with ligase
stop the gene from being expressed
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Why The marker lets them identify which cells have taken up the DNA.
8
Multiple choice · Hard
Only some treated cells incorporate the DNA fragment because:
uptake of the plasmid is a random, low-efficiency process
every cell always takes up DNA
the DNA fragment kills most cells
antibiotics force uptake in all cells
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Why Plasmid uptake is a random, low-efficiency process.
9
Multiple choice · Easy
Transformed cells are identified by growing the cells on a medium containing:
the antibiotic to which the marker gene gives resistance
pure water only
glucose only
the restriction enzyme
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Why Only cells with the resistance gene survive the antibiotic.
10
Fill in the blank · Medium
A gene used to identify cells that have taken up a plasmid is called a
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Answer:
selectable / selection
Why Selectable markers reveal transformed cells.
Key terms in Biotechnology (Elective)
Biotechnology: The use of living organisms or their components to make useful products or processes.
Genetic engineering: The deliberate alteration of an organism's genes to give it new characteristics.
Genetic modification: Changing the genetic material of an organism using biotechnology.
Recombinant DNA: DNA formed by combining genetic material from different sources.
Gene: A length of DNA coding for a protein that can be transferred between organisms.
Vector: A carrier such as a plasmid or virus used to transfer a gene into a host cell.
Plasmid: A small circular piece of bacterial DNA often used as a vector in genetic engineering.
Restriction enzyme: An enzyme that cuts DNA at a specific base sequence.
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