Hello, this is my biology assignment. I filled the answer's but I just need your help to correct me if I'm wrong Thank you.

1) The discovery of restriction endonucleases was crucial to the development of recombinant DNA technology because these enzymes.
a) always cut DNA at either end of a gene
b) always cut DNA leaving unpaired lengths of bases that have a charge.
c) cut DNA at specific and predictable sequences of bases
d) tag DNA so that individual fragments can be identified
e) all cut DNA leaving sticky ends

My answer: b

2) The following are all steps in the production of a bacterium having recombinant DNA, which includes an inserted non bacterial gene. They are in random order.
1. gel electrophoresis of plasmid DNA from bacteria in colonies showing antibiotic resistance
2. sticky nds are allowed to pair up
3. a restriction endonuclease is used to remove the gene to be inserted from its source and also to cut open a plasmid that includes a gene for antibiotic resistance
4. the bacterial colonies are treated with antibiotic
5. treatment with ligase
6. transformation

The correct order of these steps is
a) 2,5,1,3,4,6
b) 4,3,6,2,5,1
c) 5,1,2,3,4,6
d) 3,2,5,6,4,1
e) 6,3,5,2,4,1

MY ANSWER : b

3) When recombinant DNA is formed, it is necessary to join the sugar-phosphate backbones of the plasmid DNA and the introduced DNA. Which of the following is used to do this?
a) heat
b) DNA polymerase
c) helicase
d) gyrase
e) ligase

MY ANSWER: d

4) You are a geneticist who is interested in a particular gene on human chromosome number eight. You have used a restriction endonuclease to produce fragments of the chromosome and cloned each fragment in a different culture of bacteria. You now need to find out which culture contains the fragment with the gene of interest. You have available to you a single-stranded radioactive DNA probe complementary to the template strand of the gene. In what order would you perform the following for each of the bacterial colonies?
1. Allow annealing between the probe and the DNA from the bacteria to occur
2. Flood the culture with the DNA probe.
3. Separate the strands of double-stranded DNA from the bacteria using heat.
4. Break open the bacteria.
5. Prepare an autoradiograph
6. Wash away unannealed probes.
a) 5,4,3,2,1,6
b) 4,3,2,1,6,5
c) 6,3,2,1,4,5
d) 2,1,3,6,5,4
e) 4,5,3,1,2,6
MY ANSWER: e

it is normal for folks to skip questions out of their field of expertise

Let's go through each question and check your answers:

1) The correct answer is: c) cut DNA at specific and predictable sequences of bases
Restriction endonucleases recognize specific DNA sequences and cut the DNA at those sequences. This ability to cut DNA at specific sites is what makes them crucial in recombinant DNA technology.

2) The correct answer is: b) 4,3,6,2,5,1
The correct order of the steps in the production of a bacterium having recombinant DNA, which includes an inserted non-bacterial gene, is:
4. the bacterial colonies are treated with antibiotic
3. a restriction endonuclease is used to remove the gene to be inserted from its source and also to cut open a plasmid that includes a gene for antibiotic resistance
6. transformation
2. sticky ends are allowed to pair up
5. treatment with ligase
1. gel electrophoresis of plasmid DNA from bacteria in colonies showing antibiotic resistance

3) The correct answer is: e) ligase
To join the sugar-phosphate backbones of the plasmid DNA and the introduced DNA, ligase is used. Ligase catalyzes the formation of phosphodiester bonds between the adjacent nucleotides of the DNA molecules.

4) The correct answer is: e) 4,5,3,1,2,6
The correct order of the steps to find the bacterial culture containing the fragment with the gene of interest is:
4. Break open the bacteria.
5. Prepare an autoradiograph
3. Separate the strands of double-stranded DNA from the bacteria using heat.
1. Allow annealing between the probe and the DNA from the bacteria to occur
2. Flood the culture with the DNA probe.
6. Wash away unannealed probes.

So, the corrected answers are:
1) c
2) b
3) e
4) e

1) The correct answer is c) cut DNA at specific and predictable sequences of bases.

Restriction endonucleases are enzymes that recognize specific sequences of bases in DNA and cut the DNA at those specific sites. These enzymes have played a crucial role in the development of recombinant DNA technology because they allow scientists to cut DNA at specific locations and create fragments with known sequences. By doing so, these enzymes enable the manipulation of DNA and the insertion of specific genes into other DNA molecules.

2) The correct order is b) 4,3,6,2,5,1.

The correct order of the steps in the production of a bacterium with recombinant DNA is as follows:
1. The bacterial colonies are treated with an antibiotic (step 4) to select for those colonies that have taken up the plasmid with the antibiotic resistance gene.
2. A restriction endonuclease is used to remove the gene to be inserted (step 3) from its source and also to cut open a plasmid that includes a gene for antibiotic resistance.
3. Transformation (step 6) is the process by which the plasmid DNA carrying the gene of interest is taken up by the bacterial cells.
4. Sticky ends are allowed to pair up (step 2) between the cut plasmid DNA and the gene of interest.
5. Treatment with ligase (step 5) is necessary to seal the gaps in the DNA after pairing the sticky ends.
6. Gel electrophoresis of plasmid DNA from bacteria in colonies showing antibiotic resistance (step 1) helps verify the presence of the recombinant DNA.

3) The correct answer is e) ligase.

Ligase is the enzyme used to join the sugar-phosphate backbones of the plasmid DNA and the introduced DNA in recombinant DNA technology. It catalyzes the formation of phosphodiester bonds between the DNA fragments, sealing them together. In other words, ligase is responsible for creating covalent bonds between the DNA strands, thereby joining them.

4) The correct order is a) 5,4,3,2,1,6.

In order to find out which culture contains the fragment with the gene of interest, the following steps need to be performed:
1. Break open the bacteria (step 4) to release the DNA.
2. Separate the strands of double-stranded DNA from the bacteria using heat (step 3) to create single-stranded DNA.
3. Flood the culture with the DNA probe (step 2), which is a single-stranded radioactive DNA complementary to the template strand of the gene of interest.
4. Allow annealing between the probe and the DNA from the bacteria to occur (step 1), which means giving them time to bind together if there is a complementary sequence.
5. Wash away unannealed probes (step 6) to remove any unbound radioactive DNA probe.
6. Prepare an autoradiograph (step 5) to visualize the radioactive DNA probe that has annealed to the DNA fragments. This will help identify the bacterial culture that contains the fragment with the gene of interest.