RECOMBINANT DNA REVIEW

1. How are genes cut into pieces, in preparation for recombinant DNA cloning?

2. What enzyme is used to securely paste a new piece of DNA into a recombinant DNA molecue? What other process is this enzyme used in?

3. How does recombinant DNA get into bacteria? Name the process and how it works.

say you have deduced that a particular genetic disorder is caused when the body cannot produce a particular enzyme, encoded by gene ABC. Therefore you compare gene ABC’s nucleotide sequence between healthy people and people who have the disorder (because they do not produce the enzyme). But the DNA nucleotide sequence from the start site of transcription to the termination point of transcription is always exactly the same for people in both groups. If this genetic disorder is caused by a mutation in the DNA, where is the mutation likely to be, and how is the mutation acting to result in these observations? Apart from the enzyme itself, what molecule’s absence from the cells of an affected person would verify this?

8. A circular plasmid of 6200 base pairs (bp) with three restriction enzyme sites at 900, 1300, and 4000 bp. You digest this plasmid, then run the digest on a gel. What are the expected DNA fragment sizes?

9. A linear plasmid of 6200 base pairs (bp) with three restriction enzyme sites at 900, 1300, and 4000 bp. You digest this plasmid, then run the digest on a gel. What are the expected DNA fragment sizes?

10. In a random sequence consisting of equal proportions of all four nucleotides, what is the average distance between restriction enzymes for a restriction enzyme with a 4-base cleavage site (hint- look for a similar problem in your book).

DNA replication requires many enzymes to accomplish the process successfully. This results in a replication process that is known to be bi-directional, semi-conservative and semi-discontinuous. You discover a new prokaryotic organism that lacks the gene coding for an DNA polymerase I enzyme, and therefore this enzyme is not made in this species. Additionally, the DNA polymerase III enzyme from this organism lacks any 3’ to 5’ nuclease activity but has 5’ to 3’ nuclease activity. Based on what you know about DNA replication and the functions of DNA polymerase I and DNA polymerase III, discuss the effect of these changes on DNA replication in this organism. Please explain your answer in full.

DNA replication requires many enzymes to accomplish the process successfully. This results in a replication process that is known to be bi-directional, semi-conservative and semi-discontinuous. You discover a new prokaryotic organism that lacks the gene coding for an RNA polymerase I enzyme, and therefore this enzyme is not made in this species. Additionally, the DNA polymerase III enzyme from this organism lacks any 3’ to 5’ nuclease activity but has 5’ to 3’ nuclease activity. Based on what you know about DNA replication and the functions of DNA polymerase I and DNA polymerase III, discuss the effect of these changes on DNA replication in this organism. Please explain your answer in full.

1. Once glucose enters a cell, it it ‘phosphorylated' in order to

Select one:

a. trap it inside the cell

b. raise its free energy (G)

c. tag it for entry into mitochondria

d. remove protons (H+)

e. A and B

2. Energy transfers always make heat energy and more disorder. This tendancy toward more disorder refers to

Select one:

a. entropy

b. a heat sink

c. the big bang

d. e=mc squared

e. heat equilibrium

3. According to the current model, an enzyme binding to its target molecule is most like

Select one:

a. a square peg in a round hole, because the enzyme can bind to a variety of target molecules

b. a lock fitting a key, because the pocket where the enzyme fits its specific target molecule is precise, and rigid

c. a hand fitting a doorknob, because the enzyme folds around its target molecule, squeezing it

d. an electric pencil sharpener, because inserting the target molecule into the enzyme causes the enzyme to cut it

4. Which cell structure is INCORRECTLY matched with its function?

Select one:

a. Rough ER: Synthesis of membrane proteins

b. Smooth ER : Assembly of new membranes

c. Lysosome : Digestion of ‘food' substances taken into cell

d. Golgi body : Receives, modifies, and exports

e. Central vacuole : Physical support

5. Which of these are NOT features of microtubules?

Select one:

a. Assists in cell support and movement

b. Controls cell locomotion by cilia and flagella

c. Made of tubulin proteins

d. Are the thickest cytoskeletal fiber

e. Needed to form durable structures like hair and fingernails

Provide a desription of the Kreb's cycle in the biosynthesis of amino acid

Some textbooks assert that histidine can provide buffering capacity at the physiological pH of 7.4.

a) Is this assertion correct?

b) What are the unprotonated (base) and protonated (acid) forms of histidine that would contribute to the buffering?

c) Is there another amino acid that could potentially provide buffering at physiological pH? If so, which one and what are the unprotonated and protonated forms of this amino acid that would ocntribute to the buffering?