1.
The term ‘clone’ comes from the colonies of identical host cells produced during the amplification of the cloned fragments.
Correct Answer
A. TRUE
Explanation
The term 'clone' refers to the identical host cells that are produced during the amplification of the cloned fragments. This means that when fragments are cloned, they result in colonies of cells that are genetically identical to each other. Therefore, the statement is true.
2.
Gene cloning is sometimes referred to as ‘molecular cloning’ to distinguish the process from the cloning of whole organisms.
Correct Answer
A. TRUE
Explanation
The statement is true because gene cloning is indeed referred to as "molecular cloning" to differentiate it from the cloning of entire organisms. Gene cloning involves the replication of specific DNA sequences, while cloning of whole organisms refers to the creation of genetically identical copies of an entire organism. By using the term "molecular cloning," it emphasizes that the cloning process is focused on duplicating specific genes or DNA fragments rather than creating identical organisms.
3.
Possible methods available for cloning procedure are the generation of DNA fragments, joining to a vector, and introducing the recombinant DNA into a host cell.
Correct Answer
A. TRUE
Explanation
The given statement is true. Cloning procedures typically involve the generation of DNA fragments, which are then joined to a vector (such as a plasmid) to create recombinant DNA. This recombinant DNA is then introduced into a host cell, which can be a bacterial cell or a eukaryotic cell, where it can be replicated and expressed. These methods are commonly used in molecular biology research to create copies of specific DNA sequences or to produce large amounts of a particular gene or protein.
4.
A short oligo(dT) primer is annealed to the poly(A) tail on the mRNA, which provides the 3’-OH group for reverse transcriptase to begin copying the mRNA.
Correct Answer
A. TRUE
Explanation
The explanation for the given correct answer is that a short oligo(dT) primer is indeed annealed to the poly(A) tail on the mRNA. This primer provides the 3'-OH group that reverse transcriptase needs in order to start copying the mRNA. This process is commonly used in reverse transcription, where mRNA is converted into complementary DNA (cDNA) using reverse transcriptase. Therefore, the statement is true.
5.
Linkers are synthesised chemically and can be added to cDNA by blunt-end ligation.
Correct Answer
A. TRUE
Explanation
Linkers are small DNA or RNA molecules that are chemically synthesized and can be added to cDNA through a process called blunt-end ligation. This involves joining the ends of the linker molecule to the ends of the cDNA molecule without the need for complementary base pairing. Therefore, the statement that linkers can be added to cDNA by blunt-end ligation is true.
6.
Correct Answer
B. Complementary DNA
7.
Correct Answer
D. Flush-ended molecule
8.
Correct Answer
B. An oligo(dT) primer
9.
Correct Answer
A. The 3-OH group
10.
Correct Answer
C. Reverse transcriptase
11.
A
colony of identical organisms; often used to describe a cell carrying a
recombinant DNA fragment.
Correct Answer
E. Clone
Explanation
A clone refers to a colony of identical organisms or cells that have been produced through the process of cloning. In the context of recombinant DNA technology, a clone can also refer to a cell that carries a recombinant DNA fragment. This means that the cell has been genetically modified to contain a specific DNA sequence or gene of interest. Cloning allows for the production of multiple copies of the same DNA fragment or organism, which can be useful for various research and practical applications.
12.
The
attachment of a sequence of identical nucleotides (e.g. AAAAA) to the end of a
nucleic acid molecule, usually referring to the synthesis of single-stranded
homopolymer extensions on the ends of a double-stranded DNA molecule.
Correct Answer
B. Homopolymer tailing
Explanation
Homopolymer tailing refers to the attachment of a sequence of identical nucleotides to the end of a nucleic acid molecule. This process usually involves the synthesis of single-stranded homopolymer extensions on the ends of a double-stranded DNA molecule. This technique is commonly used in molecular biology to add specific sequences to the ends of DNA molecules, which can be useful for various applications such as cloning, sequencing, and gene expression studies.
13.
A
collection of clones prepared from the mRNA of a given cell or tissue type,
representing the genetic information expressed by such cells.
Correct Answer
C. CDNA library
Explanation
A cDNA library is a collection of clones that are prepared from the mRNA of a specific cell or tissue type. These clones represent the genetic information that is expressed by the cells. cDNA is synthesized from the mRNA using the enzyme reverse transcriptase, which converts the mRNA into complementary DNA (cDNA). This cDNA can then be inserted into a vector and cloned to create a library of clones that represent the genes expressed in the original cells. The cDNA library is useful for studying gene expression and identifying genes that are active in specific cell types or under certain conditions.
14.
A DNA molecule composed of a number of individual pieces joined together via cohesive ends.
Correct Answer
A. Concatemer
Explanation
A DNA molecule composed of a number of individual pieces joined together via cohesive ends is called a concatemer. It is formed when multiple DNA fragments are ligated together, resulting in a single long DNA molecule. This can occur during DNA replication or in laboratory techniques such as PCR. Concatemers are commonly used in cloning and sequencing experiments to amplify and analyze specific DNA regions.
15.
A collection of clones that together represent the entire genome of an organism.
Correct Answer
D. Genomic library
Explanation
A genomic library is a collection of clones that together represent the entire genome of an organism. This means that the library contains copies of all the genes and non-coding regions of the DNA of the organism. These clones can be used for various purposes, such as studying gene expression, identifying specific genes, or comparing genomes between different organisms.
16.
Artificial chromosomes such as YACs or BACs can be used to clone large fragments of DNA (in excess of several hundred kb).
Correct Answer
A. TRUE
Explanation
Artificial chromosomes like YACs or BACs are capable of cloning large fragments of DNA, typically exceeding several hundred kilobases (kb). This is because they have the ability to accommodate and replicate large DNA inserts, making them valuable tools in genetic engineering and cloning experiments.
17.
Regulatory control of the expression of cloned genes can be achieved by selecting appropriate vector/host systems.
Correct Answer
A. TRUE
Explanation
The statement is true because regulatory control of gene expression can be achieved by selecting the appropriate vector/host systems. Different vector/host systems have different promoters and regulatory elements that can control the expression of the cloned genes. By choosing the right vector/host system, researchers can manipulate the expression of the cloned genes to suit their experimental needs.
18.
The use of a suitable promoter is a key element in achieving the expression of a gene by means of a cloned cDNA sequence.
Correct Answer
A. TRUE
Explanation
A promoter is a region of DNA that initiates the transcription of a particular gene. It plays a crucial role in gene expression as it determines when and where a gene will be expressed. In the context of using a cloned cDNA sequence, a suitable promoter is necessary to ensure that the gene is expressed effectively. Without a suitable promoter, the gene may not be transcribed or may not be expressed at the desired level. Therefore, the statement that the use of a suitable promoter is a key element in achieving the expression of a gene by means of a cloned cDNA sequence is true.
19.
Cloned cDNA can be used to express genes by enabling the synthesis of the protein in a suitable host system.
Correct Answer
A. TRUE
Explanation
Cloned cDNA, which is a copy of the coding sequence of a gene, can be used to express genes by allowing the production of protein in a host system that is compatible with the cDNA. This is achieved by inserting the cDNA into an expression vector, which is then introduced into the host cells. The host cells will then use the cDNA as a template to synthesize the corresponding protein. Therefore, the statement is true.
20.
Amplification of genomic libraries is often used to generate copies of the original primary clones.
Correct Answer
A. TRUE
Explanation
Amplification of genomic libraries is a common technique used to produce multiple copies of the original primary clones. This process allows researchers to generate a sufficient amount of DNA for further analysis or experimentation. By amplifying the genomic libraries, scientists can obtain larger quantities of DNA samples, enabling them to perform various molecular biology techniques such as sequencing, cloning, and gene expression analysis. Therefore, the statement that amplification of genomic libraries is often used to generate copies of the original primary clones is true.