Missed Practice Questions Flashcards

1
Q

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

A

D) All of the above

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2
Q

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

A

prevent nontransformed bacteria from yielding colonies.

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3
Q

Phorphoramidite synthesis of DNA uses protecting groups to:

A

prevent the addition of multiple nucleotides during each cycle.

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4
Q

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

A

D) all of the above

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5
Q

What is a common type of protein secondary structure?

A

alpha helix

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6
Q

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

A

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

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7
Q

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

A

The hydrophobic effect

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8
Q

What are organisms living in high temperature environments?

A

thermophiles

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9
Q

Define Vector:

A

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

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10
Q

Define Inclusion Body:

A

microscopic aggregates of protein inside the cell

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11
Q

How do you determine single step coupling efficiency?

A

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

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12
Q

What are some forces that stabilize protein structure?

A

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

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13
Q

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

A

(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

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14
Q

What is one reason for artificially synthesizing a gene?

A

The gene is eukaryotic and contains both exons and introns

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15
Q

What does the melting temperature of DNA depend on?

A

1) sequence
2) length
3) solution cation concentration

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16
Q

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

A

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

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17
Q

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

A

T

18
Q

Define Expression Vector

A

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

19
Q

Define Ethidium Bromide

A

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

20
Q

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

A

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

21
Q

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

A

Allows easy determination of DNA concentration

22
Q

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

A

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.

23
Q

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

A

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

24
Q

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

A

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

25
Q

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

A

Dnase I

26
Q

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

A

Dimethoxytrityl groups (DMT)

27
Q

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

A

AmpR

28
Q

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

A

Polylinker (another name for MCS)

29
Q

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

A

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

30
Q

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

A

NO

31
Q

How is annealing defined?

A

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

32
Q

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:

A

LINE-1

33
Q

what is the difference between cloning and expression vectors?

A

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).

34
Q

Where do Restriction Endonucleases leave the phosphate group?

A

They leave a HPO4- at the 5’ end.

35
Q

What are the components of a retrovirus?

A

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

NOT DNA

36
Q

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

A

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

37
Q

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

A

reverse transcriptase

38
Q

A typical yield of in vitro protein folding

A

1%

39
Q

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

A

Acetyl groups

40
Q

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

A

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

41
Q

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

A

2