Ch-9: Biotechnology - Principles and Processes12 Questions
Before You Practice
Try each question on your own first. Use the Show Answer button only after you have selected your option, then read the explanation and revise the related concept from your chapter notes.
1. The two core techniques that form the foundation of modern biotechnology are:
A. Genetic engineering and bioprocess technology
B. Microbiology and cell biology alone
C. Classical breeding methods alone
D. Fermentation technology alone
Answer: A. Genetic engineering and bioprocess technology
Explanation: Modern biotechnology combines the ability to alter genetic material (genetic engineering) with large-scale production processes (bioprocess technology).
2. Restriction endonucleases are specialized enzymes that function to:
A. Cut DNA molecules at specific recognition sequences
B. Join separate DNA fragments together
C. Synthesize entirely new DNA strands
D. Degrade RNA molecules exclusively
Answer: A. Cut DNA molecules at specific recognition sequences
Explanation: These 'molecular scissors' recognize specific nucleotide sequences and cleave the DNA at or near those sites.
3. The enzyme used to join (ligate) DNA fragments together during recombinant DNA technology is:
A. DNA ligase
B. DNA polymerase
C. Restriction endonuclease
D. RNA polymerase
Answer: A. DNA ligase
Explanation: DNA ligase catalyzes the formation of phosphodiester bonds, sealing together DNA fragments to form a continuous strand.
4. A vector commonly used to carry and introduce foreign DNA into a host cell is a:
A. Plasmid
B. Ribosome
C. Mitochondrion
D. Lysosome
Answer: A. Plasmid
Explanation: Plasmids are small, circular, self-replicating DNA molecules commonly used as carriers to introduce foreign genes into host cells.
5. The Polymerase Chain Reaction (PCR) technique is primarily used to:
A. Rapidly amplify a specific segment of DNA into many copies
B. Cut DNA molecules at specific recognition sites
C. Sequence an organism's entire genome directly
D. Translate an mRNA sequence into a protein
Answer: A. Rapidly amplify a specific segment of DNA into many copies
Explanation: PCR uses repeated cycles of heating and cooling, along with a heat-stable DNA polymerase, to exponentially amplify a targeted DNA sequence.
6. Gel electrophoresis is a laboratory technique used to:
A. Separate DNA fragments primarily based on their size
B. Amplify a given DNA sequence
C. Cut DNA molecules at specific sites
D. Synthesize entirely new proteins
Answer: A. Separate DNA fragments primarily based on their size
Explanation: Under an applied electric field, smaller DNA fragments move faster through the gel matrix than larger ones, allowing separation by size.
7. Competent cells, used during the process of genetic transformation, are host cells that have been specially treated to:
A. Take up foreign DNA more readily from their surroundings
B. Naturally resist all types of antibiotics
C. Produce significantly more cellular energy
D. Divide at an unusually rapid rate
Answer: A. Take up foreign DNA more readily from their surroundings
Explanation: Treatments such as exposure to calcium chloride make bacterial cell walls more permeable, allowing foreign DNA to enter more easily.
8. The bacterium most commonly used as a host organism in recombinant DNA technology experiments is:
A. Escherichia coli
B. Streptococcus
C. Rhizobium
D. Lactobacillus
Answer: A. Escherichia coli
Explanation: E. coli is favoured as a host due to its well-understood genetics, rapid growth rate, and ease of genetic manipulation.
9. A bioreactor is a specialized vessel primarily used to:
A. Grow large volumes of cells for the industrial production of useful biological products
B. Cut and join DNA fragments together
C. Separate DNA fragments according to their size
D. Determine the complete sequence of a DNA molecule
Answer: A. Grow large volumes of cells for the industrial production of useful biological products
Explanation: Bioreactors provide controlled, optimal conditions (temperature, pH, oxygen, nutrients) for large-scale cultivation of cells or microbes.
10. Downstream processing in a biotechnological process refers to:
A. The purification and processing of a product after it has been biosynthesized
B. The very first step involved in gene cloning
C. Solely the process of DNA amplification
D. Solely the step of cutting DNA with enzymes
Answer: A. The purification and processing of a product after it has been biosynthesized
Explanation: After a desired product has been synthesized (e.g., in a bioreactor), it must undergo separation, purification, and formulation before use.
11. The origin of replication (ori) sequence present in a vector is responsible for:
A. Enabling the vector to replicate independently within the host cell
B. Cutting any foreign DNA that is inserted
C. Simply marking the vector for later selection
D. Encoding a completely unrelated foreign protein
Answer: A. Enabling the vector to replicate independently within the host cell
Explanation: The origin of replication allows a vector, once introduced into a host cell, to be copied along with the host's own genetic material.
12. Selectable marker genes present in a cloning vector primarily help to:
A. Identify and eliminate host cells that have not been successfully transformed
B. Increase the overall mutation rate of the host cell
C. Make the vector replicate at a significantly faster rate
D. Cut foreign DNA at specific recognition sites
Answer: A. Identify and eliminate host cells that have not been successfully transformed
Explanation: Marker genes, often conferring antibiotic resistance, allow researchers to distinguish successfully transformed cells from untransformed ones.
