Missed Practice Questions

Question 1

Secreted Proteins
A) Begin with a signal peptide
B) Are translocated into the ER during translation
C) can be glycosylated
D) all
E) None

Answer 1

D) All of the above

Question 2

Antibiotics are added to a solid culture medium for plating bacteria transformed with recombinant plasmids to:

Answer 2

prevent nontransformed bacteria from yielding colonies.

Question 3

Phorphoramidite synthesis of DNA uses protecting groups to:

Answer 3

prevent the addition of multiple nucleotides during each cycle.

Question 4

Reverse transcriptase
A) is necessary for the life cycle of retroviruses
B) catalyzes DNA polymerization using an RNA template
C) requires priming by a short oligonucleotide
D) All of the above
E) none of the above

Answer 4

D) all of the above

Question 5

What is a common type of protein secondary structure?

Answer 5

alpha helix

Question 6

What are some difference between the cytoplasm and ER that are important to protein folding and structure?

Answer 6

1) Oxidizing Environment
2) Molecular Chaperones
3) Foldases
4) Post-Translational glycosylation

Question 7

What is the primary force driving the rapid compaction of unfolded proteins?

Answer 7

The hydrophobic effect

Question 8

What are organisms living in high temperature environments?

Answer 8

thermophiles

Question 9

Define Vector:

Answer 9

a vector is a tool for introducing a gene into a cell in a functional form that can propogate

Question 10

Define Inclusion Body:

Answer 10

microscopic aggregates of protein inside the cell

Question 11

How do you determine single step coupling efficiency?

Answer 11

YIELD=(efficiency)^(n-1)
where n = oligonucleotide length

Question 12

What are some forces that stabilize protein structure?

Answer 12

1) Pi stacking
2) H-bonding
3) Ionic Bonding
4) Hydrophobic Bonding
5) Covalent Bonding (Disulfide Bonds)
6) Van der Waals

Question 13

How do you find the correct number of product molecules from PCR?

Answer 13

(starting molecules)(2)^(n-2), where n = #cycles

then use avagadro’s number to conver to moles.

then use 1bp=660g/mol to get mass

Question 14

What is one reason for artificially synthesizing a gene?

Answer 14

The gene is eukaryotic and contains both exons and introns

Question 15

What does the melting temperature of DNA depend on?

Answer 15

1) sequence
2) length
3) solution cation concentration

Question 16

T/F: DNA ligase catalyzes hybridization of complementary sticky ends

Answer 16

F (hybridization in creating double strands, ligating is just joining end to end)

Question 17

T/F: cDNA synthesis makes use of the polyA tail of eukaryotic mRNA and a complementary polyT primer for priming reverse transcriptase

Answer 17

T

Question 18

Define Expression Vector

Answer 18

an expression vector is a plasmid with needed genetic elements for introducing DNA into cells and causing gene expression

Question 19

Define Ethidium Bromide

Answer 19

Chemical that intercolates into DNA and becomes fluorescent: helps to visualize DNA in gels.

Question 20

How are beads to which the first nucleotide are attached during artificial DNA synthesis important?

Answer 20

Allow easy separation of oligo. products from extra reactants during cyclic synthesis.

Question 21

How is the absorption of UV light by DNA bases significant?

Answer 21

Allows easy determination of DNA concentration

Question 22

How do you approach a problem asking you to sketch band patterns of chain terminating sequencing?

Answer 22

1) Write out the complementary strand
2) cut off where the primer stops
3) draw bands going from shortest at the bottom to furthest at the top - IF THE PRIMER IS RADIOLBELED DRAW THE PRIMER AS A BAND FOR EACH BASE AT THE LINE IT WOULD CUT OFF!! do not draw a band for the primer if it is unlabeled.

Question 23

What is the primary difference between an expression vector and a cloning vector?

Answer 23

The presence of a transcriptional promoter compatible with the relevant host organism.

Question 24

Why is solid phase synthesis is an advantage for processes such as oligonucleotide synthesis?

Answer 24

rapid phase separation of products from other reaction components is possible at each step.

Question 25

Which of the following is not required for cDNA synthesis?
1) polyadeylated mRNA
2) DNase I
3) reverse transcriptase
4) deoxynucleotide triphosphates

Answer 25

Dnase I

Question 26

What is used as a protecting group for the 5’ -OH group of nucleotides during artificial DNA synthesis?

Answer 26

Dimethoxytrityl groups (DMT)

Question 27

What is a plasmid genetic element that is commonly used to allow selection of transformed E.Coli?

Answer 27

AmpR

Question 28

What is a short region of a plasmid containing many restriction sites?

Answer 28

Polylinker (another name for MCS)

Question 29

If given absorbance and concentration how do you find length of DNA?

Answer 29

Do the STOICH like you could for a vector/plasmid problem!!

Question 30

is alternative splicing a post-translational modification that might be made to a secreted protein in a eukaryote?

Answer 30

NO

Question 31

How is annealing defined?

Answer 31

The changing of temperature (usually cooling) in a slow or defined manner.

Question 32

What is a genetic element making up almost 15% of the human genome, capable of self-replicating via a reverse transcriptase that it encodes and inserting further copies of itself into the genome is:

Answer 32

LINE-1

Question 33

what is the difference between cloning and expression vectors?

Answer 33

A cloning vector is used to acquire multiple copies of the foreign DNA fragment (gene of interest).

An expression vector is utilised to acquire the gene product, which might be RNA or protein, of the DNA (gene of interest).

Question 34

Where do Restriction Endonucleases leave the phosphate group?

Answer 34

They leave a HPO4- at the 5’ end.

Question 35

What are the components of a retrovirus?

Answer 35

1) RNA
2) capsid proteins
3) lipid membrane (envelope)
4) envelope proteins

NOT DNA

Question 36

During DNA synthesis by the phsophoramidite method, nucleotides to be added to the first one are:

Answer 36

Initially protected at the 3’ OH group by a phosphoramidite group

Question 37

In making cDNA, synthesis of the first DNA strand is catalyzed by:

Answer 37

reverse transcriptase

Question 38

A typical yield of in vitro protein folding

Answer 38

1%

Question 39

What is the protecting group used to “cap” unreacted 5’ -OH groups following each nucleotide addition step during artificial DNA synthesis?

Answer 39

Acetyl groups

Question 40

What are the post translation modification that can be made to a secreted protein?

Answer 40

1) disulfide bond formation
2) glycosylation
3) proteolytic cleavage

Question 41

How many membrane layers does the cell wall of E.Coli and other gram negatice bacteria include?

Answer 41

2