Question 1

Which of the following is not an agricultural product made by DNA techniques?

Accepted Answer

D

Question 2

Figure 9.3
 
-In Figure 9.3, the vector is

Accepted Answer

Plasmids are small, circular, double-stranded DNA molecules that are distinct from a cell's chromosomal DNA. They are commonly used as vectors in molecular biology to clone, transfer, and manipulate genes.

Question 3

The reaction catalyzed by reverse transcriptase.

Accepted Answer

Reverse transcriptase catalyzes the synthesis of complementary DNA (cDNA) from an mRNA template.

Question 4

The value of cDNA in recombinant DNA is that

Accepted Answer

cDNA, or complementary DNA, is synthesized from an mRNA template in a process called reverse transcription. Since mRNA is processed in eukaryotic cells to remove introns, cDNA lacks introns and retains only the exons, which are the coding regions of the gene.

Question 5

Foreign DNA can be inserted into cells by all of the following except

Accepted Answer

All the methods listed (A gene gun, Electroporation, Transformation, Protoplast fusion) are indeed used to insert foreign DNA into cells. Each technique has its own application and suitability depending on the type of cells being targeted and the desired outcome of the genetic modification.

Question 6

Figure 9.1
 
-In Figure 9.1, after digestion with the appropriate restriction enzyme, what is the smallest piece containing the ampicillin- resistance (amp) gene?

Accepted Answer

The answer of Figure 9.1
 
-In Figure 9.1, after digestion...

Question 7

The following steps must be performed to make a bacterium produce human protein X: 1- Translation; 2- Restriction enzyme; 3- Prokaryotic transcription; 4- DNA ligase;
5- Transformation; 6- Eukaryotic transcription; 7- Reverse transcription. Put the steps in the correct sequence.

Accepted Answer

To produce a human protein in a bacterium, the process starts with eukaryotic transcription (6) of the human gene, followed by reverse transcription (7) to create cDNA from the mRNA. This cDNA is then cut with a restriction enzyme (2) and joined into a bacterial plasmid using DNA ligase (4). The plasmid is introduced into the bacterium by transformation (5), followed by prokaryotic transcription (3) of the inserted human gene and finally translation (1) to produce the human protein.

Question 8

You have a small gene that you wish replicated by PCR. You add radioactively labeled nucleotides to the PCR machine. After 3 replication cycles, how many double- stranded DNA molecules do you have?

Accepted Answer

After 3 replication cycles of PCR, the number of double-stranded DNA molecules would be 8. PCR doubles the amount of DNA with each cycle, so after 3 cycles, it would be 2^3 = 8.

Question 9

Which organism degrades PCBs and has been engineered to produce BT toxin?

Accepted Answer

Pseudomonas has been genetically engineered to degrade PCBs and can also be engineered to produce BT toxin, showcasing its versatility in bioremediation and biological control applications.

Question 10

Figure 9.3
 
-In Figure 9.3, the process required in step 5 is

Accepted Answer

Transformation is the process used in step 5, where a foreign DNA is introduced into a cell, allowing for genetic modification.

Question 11

Which of the following can be used to make recombinant DNA?

Accepted Answer

All of the options listed can be used in various methods to create or manipulate recombinant DNA. Protoplast fusion involves the merging of cell membranes to combine genetic material, transformation involves introducing foreign DNA into a cell, microinjection directly inserts DNA into cells, and while tungsten bullets are typically used in biolistic particle delivery systems for plant cells, they can be involved in the process of introducing recombinant DNA into an organism.

Question 12

The reaction catalyzed by DNA polymerase.

Accepted Answer

DNA polymerase catalyzes the synthesis of DNA from a DNA template, which is the process of DNA replication.

Question 13

Figure 9.3
 
-In Figure 9.3, the resulting organism (a) is

Accepted Answer

The resulting organism is a tomato plant, which can be inferred from the context of the question, as Pseudomonas fluorescens, Bacillus thuringiensis, and E. coli are bacteria, and a plant × Pseudomonas hybrid is not a standard outcome of genetic engineering or cross-species hybridization in the context provided.

Question 14

You have a small gene that you wish replicated by PCR. You add radioactively labeled nucleotides to the PCR thermocycler. After 3 replication cycles, what percentage of the DNA single- strands are radioactively labeled?

Accepted Answer

After 3 cycles of PCR, 87.5% of the DNA strands are radioactively labeled. This is because, in each cycle, the newly synthesized strands incorporate the labeled nucleotides, doubling the amount of labeled DNA. After the first cycle, 50% is labeled (the new strands), after the second cycle, 75% (half of the original strands plus all new strands), and after the third cycle, 87.5% (half of the remaining unlabeled original strands plus all new strands).

Question 15

Subunit vaccines can be made by genetic modification of yeast cells. A side effect of these vaccines might be

Accepted Answer

The answer of Subunit vaccines can be made by genetic...

Question 16

Which of the following methods of making rDNA could be described as "hit or miss"?

Accepted Answer

Protoplast fusion is considered a "hit or miss" method for making recombinant DNA (rDNA) because it involves the fusion of entire cell contents, which can lead to unpredictable and random combinations of genetic material. This method does not allow for the precise control over which DNA sequences are combined, making it less targeted than techniques like cloning or transformation.

Question 17

A restriction fragment is

Accepted Answer

A restriction fragment is a segment of DNA that has been cut by restriction enzymes. These enzymes recognize specific sequences in the DNA and cut the DNA at or near these sites, producing fragments of varying lengths.

Question 18

Suicide genes can be controlled by the fimbriae- gene operator. This would result in the death of

Accepted Answer

Suicide genes controlled by the fimbriae-gene operator would lead to the death of cells making fimbriae, as the expression of these genes would be directly linked to the activation of the fimbriae-gene operator, which is specific to the process of fimbriae production.

Question 19

A population of cells carrying a desired plasmid is called a

Accepted Answer

A population of cells carrying a desired plasmid is referred to as a clone. This term is used because all the cells in the population are genetically identical to each other, having originated from a single ancestor cell that was transformed with the plasmid.

Question 20

Which of the following techniques is used to alter one amino acid in protein?

Accepted Answer

Site-directed mutagenesis is specifically designed to introduce precise changes at specific sites in a DNA sequence, thereby allowing the alteration of individual amino acids in a protein.

Quiz 9: Biotechnology and Recombinant DNA