Chapter 6 · Molecular Technology: practice questions
Chapter 6 — Nucleic Acids and Protein Synthesis · Biology. These are 10 questions from the Magmo3 bank on this lesson, from easy to hard. Solve each one, then open "Show answer and explanation". Magmo3 has 33 questions on this lesson, each with an explanation.
Which of the following is an application of genetic fingerprinting?
ARefrigerating food to keep it fresh for longer
BIdentifying the victims of accidents and disasters
CLighting homes and streets with electric lamps
DIncreasing the speed of cars and reducing fuel use
Show answer and explanation
Correct answer: (B) Identifying the victims of accidents and disasters
Explanation: Genetic fingerprinting is used to identify people and disaster victims because each person has a distinctive fingerprint.
Question 2Easy
What is a genetic (DNA) fingerprint?
AThe shape of a chromosome under the microscope during cell division
BA type of protein in the blood that is the same in all individuals
CA distinctive DNA pattern that differs from one individual to another
DAn ordinary fingerprint printed from the lines on the fingertips
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Correct answer: (C) A distinctive DNA pattern that differs from one individual to another
Explanation: A genetic fingerprint is a unique DNA pattern that distinguishes each person from everyone else.
Question 3Easy
What is the main goal of the polymerase chain reaction (PCR)?
AProducing millions of copies of a specific DNA fragment
BSeparating cells from one another
CBreaking a DNA molecule down into sugar units
DConverting DNA directly into protein
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Correct answer: (A) Producing millions of copies of a specific DNA fragment
Explanation: PCR amplifies a small DNA fragment into millions of copies, allowing us to study an extremely tiny sample.
Question 4Medium
In genetic fingerprint analysis, DNA fragments are separated by size using:
ACentrifugation only
BThe light microscope
CGel electrophoresis
DDistillation
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Correct answer: (C) Gel electrophoresis
Explanation: Gel electrophoresis separates DNA fragments by size, revealing the distinctive band pattern of the fingerprint.
Question 5Medium
Genetic fingerprinting relies on differences in what between individuals?
ABlood type only, as determined by the ABO blood groups
BThe repeated sequences in the non-coding regions of DNA
CThe number of red blood cells in each drop of blood
DEye colour only, as seen in the iris of each person
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Correct answer: (B) The repeated sequences in the non-coding regions of DNA
Explanation: The fingerprint relies on repeated sequences (in the non-coding regions) whose number differs from one person to another.
Question 6Medium
Which of the following is considered an old (traditional) application of biotechnology?
AProducing insulin with genetically modified bacteria
BMaking bread, yoghurt, and cheese by fermentation
CGene therapy
DGenetic fingerprinting
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Correct answer: (B) Making bread, yoghurt, and cheese by fermentation
Explanation: Fermentation in making bread, yoghurt, and cheese is one of the oldest forms of biotechnology, using microorganisms.
Question 7Medium
The different body cells of one person (such as blood and skin cells) have a genetic fingerprint that is:
AThe same (identical) in all cells
BPresent only in blood cells
CChanging every year
DCompletely different in each organ
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Correct answer: (A) The same (identical) in all cells
Explanation: All of an individual's cells contain the same DNA, so their genetic fingerprint is the same whether taken from blood, skin, or hair.
Question 8Hard
Which is a correct match between a PCR step and its approximate temperature?
AExtension at 72 degrees Celsius
BAnnealing at 95 degrees Celsius
CDenaturation at 55 degrees Celsius
DDenaturation at 37 degrees Celsius
Show answer and explanation
Correct answer: (A) Extension at 72 degrees Celsius
Explanation: Extension occurs at about 72 degrees Celsius (Taq's optimum), denaturation at about 95 degrees Celsius, and annealing at about 55 degrees Celsius.
Question 9Hard
If the annealing step of a PCR cycle were run at 95 °C instead of about 55 °C, what would happen?
AThe primers would bind, but the new strands would contain uracil
BTaq polymerase would be destroyed, so the strands would join back together
CThe DNA would be copied faster, because the strands stay apart
DThe primers could not bind to the single strands, so no new DNA would be made
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Correct answer: (D) The primers could not bind to the single strands, so no new DNA would be made
Explanation: At 95 °C, hydrogen bonds cannot hold, so the primers cannot attach to their complementary sequences. Without a primer, the polymerase has no start point. Taq is heat-resistant, so it is not destroyed.
Question 10Hard
A restriction enzyme has 2 recognition sites in a circular plasmid and 2 in a linear DNA molecule. How many fragments does each give when fully cut?
APlasmid 2, linear DNA 2
BPlasmid 2, linear DNA 3
CPlasmid 3, linear DNA 3
DPlasmid 3, linear DNA 2
Show answer and explanation
Correct answer: (B) Plasmid 2, linear DNA 3
Explanation: A circle has no ends, so n cuts give n pieces. A line already has two ends, so n cuts give n + 1 pieces: 2 for the plasmid and 3 for the linear DNA.