Biology Aptitude Test for Schools on “Biotechnology – Processes of Recombinant DNA Technology – 2”.
1. The antibiotic resistance gene can be used as ________ marker for selecting transformants.
a) selectable
b) differential
c) similar
d) radioactive
Answer: a
Clarification: The antibiotic resistance gene can be used as a selectable marker for selecting transformants. This gene confers the trait for artificial selection and may code for resistance to any antibiotic such as ampicillin, penicillin, kanamycin, tetracycline, etc. The successful transformants will grow on antibiotic-containing media.
2. The common bacteria used in genetic engineering is _____
a) S.typhi
b) E.coli
c) Rhizobium
d) S.aureus
Answer: b
Clarification: E.coli is the bacteria most commonly used in genetic engineering. It is a model organism. It can be easily and inexpensively cultured within a laboratory. It grows at a faster rate and has a doubling time of approximately 20 minutes.
3. Recombinant DNA technology is associated with _______
a) Christian Gram
b) C. Darwin
c) Robert Koch
d) Herbert Boyer
Answer: d
Clarification: Recombinant DNA technology is associated with Herbert Boyer since he invented it along with Stanley Cohen. He worked on restriction enzymes found in E.coli. He invented DNA cloning which led to the discovery of several recombinant proteins such as insulin.
4. If any protein-encoding gene is expressed in a heterologous host, it is called a _______ protein.
a) pure
b) mixed
c) recombinant
d) similar
Answer: c
Clarification: A protein encoded by a gene of recombinant DNA is called a recombinant protein. The heterologous host is the host responsible for producing proteins that they are not supposed to produce that is they express the genes which are artificially incorporated within them.
5. Which culture system is used to obtain cells in the exponential phase?
a) Single
b) Monochronous
c) Continuous
d) Batch
Answer: c
Clarification: The continuous culture system is used to obtain the cells in the exponential phase. In continuous culture, the fresh media is added from one side while the used media is simultaneously drained from the other side. This helps to obtain cells in a single phase.
6. _______ culturing method produces higher biomass and higher yield of the desired product.
a) Batch
b) Continuous
c) Mixed
d) Hybrid
Answer: b
Clarification: The continuous culturing method produces the cells which are in the same phase i.e. exponential phase. Since all cells are in the same phase. This type of culturing method produces higher biomass and yields the maximum desired product.
7. ________ growth conditions are required to obtain the maximum yield.
a) Low
b) High
c) Equal
d) Optimum
Answer: d
Clarification: Optimum means favorable. These conditions favor the growth of bacteria and maximum growth is seen when the cells are provided with optimum conditions. Maximum growth leads to maximum product yield.
8. How many stages does a bacterial growth curve have?
a) 5
b) 1
c) 4
d) 3
Answer: c
Clarification: A typical bacterial growth curve has four distinct phases, namely log phase, lag/exponential phase, stationary phase, and death/decline phase. Bacteria divide with the help of binary fission. Few other micro-organisms such as algae, protozoa, yeasts also show these same growth phases.
9. What facilitates the even mixing of ingredients within a bioreactor?
a) Pipe
b) Motor
c) Stirrer
d) Broth
Answer: c
Clarification: Bioreactor is a device or vessel which helps in carrying out various biological reactions providing them optimum conditions. The stirrer facilitates the even mixing of ingredients like broth, the air in a bioreactor. This stirrer is also known as impellers.
10. Downstream processing also involves _________
a) separation and purification
b) mixing and hybridization
c) separation and hybridization
d) mixing and purification
Answer: a
Clarification: Downstream processing is the various stages that occur after the completion of the fermentation process. It refers to the recovery and purification of various biosynthetic products that are beneficial for humans. It also involves stages such as separation and purification.
11. Log phase is also known as _________
a) lag phase
b) exponential phase
c) stationary phase
d) decline phase
Answer: b
Clarification: The log (logarithmic) phase of the bacterial growth curve is also known as the exponential phase. It is the second phase of the bacterial growth curve. In this phase the bacteria that have adapted to the new environment doubles. Thus, the maximum growth rate is seen in this phase.
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