Biology: Part III

Question 1

Which of the following experimental treatments proved the “transforming principle” (later identified as DNA) is the genetic material?

A) Infection of mice with pathogenic strain resulting in no disease.

B) Infection of mice with E. coli strain showing it can cause death.

C) Infection of live pathogenic strain mixed with dead non-pathogenic strain, causing disease.

D) Infection of dead pathogenic strain mixed with live non-pathogenic strain, causing disease.

E) Infection of dead pathogenic strain mixed with dead E.coli strain, causing disease.

Answer 1

D

Question 2

Which of the following will not be able to transform non-pathogenic bacteria to become pathogenic bacteria?

A) Cell extract from pathogenic bacteria treated with protease

B) Cell extract from pathogenic bacteria treated with RNase

C) Cell extract from pathogenic bacteria treated with DNase

D) Cell extract from pathogenic bacteria not treated with any enzymes

E) Pathogenic bacteria

Answer 2

C

Question 3

If a RNA virus with protein capsid was allowed to replicate inside a bacterial cell in the presence of radioactive sulfur. The resulting virus was purified and allowed to infect non-radioactive bacteria. Then the cells were centrifuged to separate the virus from bacteria. Which fraction will contain the highest radioactivity?

A) The bacteria in the pellet.

B) RNA inside bacterial pellet.

C) Bacteria and RNA in the virus.

D) Protein coat of virus in the supernatant.

E) Both protein coat and RNA of the virus.

Answer 3

D

Question 4

All of the following are true about DNA structure except __________.

A) The purines are H-bonded to pyrimidines.

B) 5’ refers to the phosphate group attached to the 5th Carbon of deoxyribose.

C) 3’ refers to the Nitrogenous base attached to the 3rd C of dexyribose.

D) The two strands run antiparallel to each other.

E) The 2nd C of deoxyribose contains only H and no oxygen.

Answer 4

C

Question 5

In an analysis of the nucleotide composition of a double stranded DNA to see which bases are equivalent in concentration, which of the following would be true?

A) A + C is same as A +T

B) A = G and C = T only

C) A + C = G + T only

D) A + T = G + C

E) All the above choices are possible.

Answer 5

C

Question 6

The composition of a viral DNA was 30%A, 20% G, 25% C and 25% T. Based on this information, we can say that this DNA is from a _______.

A) Double stranded RNA virus.

B) Single stranded RNA virus.

C) Double stranded DNA virus.

D) Single stranded DNA virus.

E) Double stranded protein virus.

Answer 6

D

Question 7

A DNA template of 5’ to 3 ‘direction is copied from the other direction starting at the 3’ end of the template DNA.
This is because _________

A) the 5’ to 3’ direction of one strand runs counter to the 5’ to 3’ direction of the other strand.

B) DNA polymerase adds nucleotides only at the 3 ‘end of the new strand.

C) base pairing create unequal spacing between the two DNA strands.

D) The helical nature of DNA makes the DNA strands copied in opposite direction.

E) Both A and B are important reasons for this process.

Answer 7

E

Question 8

Is DNA replication endergonic or exergonic?

A) Endergonic

B) Exergonic

Answer 8

B

Question 9

What is the relationship between DNA, a gene, and a chromosome?

A) A chromosome contains hundreds of genes, which are composed of protein.

B) A gene contains hundreds of chromosomes, which are composed of DNA.

C) A gene contains hundreds of chromosomes, which are composed of protein.

D) A gene is composed of DNA, but there is no relationship to a chromosome.

E) A chromosome can contain hundreds of genes, which are composed of DNA.

Answer 9

E

Question 10

Which of the following will be the mRNA transcribed from the DNA? Note only the 5’ to 3’ strand is shown. 5’-Promoter…………ATGCCGGGACTCTTT-3’.

A) 5’-UACGGCCCUGAGAAA-3’

B) 3’-UACGGCCCUGAGAAA-5’

C) 5’-AUGCCGGGACUCUUU-3’

D) 3’-AUGCCGGGACUCUUU-5’

E) 3’-ATGCCGGGACTCTTT-5’

Answer 10

C

Question 11

An eukaryoric gene contains 3 exons and 2 introns. How many possible combinations of proteins it can make with at least 2 exons expressed in the protein.

Answer 11

3

Question 12

If the gene encoding enzyme involved in the following biochecmical pathway of

A –> B –> C –> D –> E

is interrupted between C and D, the fungus will be able to grow in the minimal medium supplemented with

A) A

B) A and B

C) A, B and C

D) D and E only

E) All A to E

Answer 12

D

Question 13

What is the sequence of a polypeptide based on the mRNA sequence

5’ UUUUCUUAUUGUCUU 3’?

A) phe-pro-asp-lys-gly

B) leu-cys-tyr-ser-phe

C) phe-ser-tyr-cys-leu

D) cys-phe-tyr-cys-leu

E) phe-leu-ile-met-val

Answer 13

C

Question 14

A possible sequence of DNA nucleotides that would make the template strand for the polypeptide sequence phe-leu-ile-val would be

A) 5’ AUG-CTG-CAG-TAT 3’.

B) 3’ AAA-AAT-ATA-ACA 5’.

C) 5’ AAA-AAT-ATA-ACA 3’.

D) 5’ TTG-CTA-CAG-TAG 3’.

E) 3’ AAA-GAA-TAA-CAA 5’.

Answer 14

E

Question 15

What will be minimal length of open reading frame encoding a protein made up of 100 amino acids?

Answer 15

300

Question 16

During translation initiation the P-site is first bound by __________.

A) Methionine-tRNA

B) Large ribosomal subunit

C) Initiation factor

D) Small ribosomal subunit

E) GTP

Answer 16

A

Question 17

Which of the following is / are important for enforcing the specificity of protein synthesis?

A) Correct tRNA being attached to the right amino acid

B) Correct codon matching the right anticodon

C) Specific mRNA finding the right kind of ribosome

D) Both A and B are needed

E) All A, B and C are essential

Answer 17

D

Question 18

Choose the answer that has these events of protein synthesis in the proper sequence. Note that all the steps in translation may NOT be included.

A peptide bond forms between the new amino acid and a polypeptide chain.
An aminoacyl-tRNA binds to the A site.
Empty tRNA leaves the P site, moves to the E site and leaves the ribosome.
A small ribosomal subunit binds with mRNA at the recognition site.
Peptidyl tRNA translocates to the P site from A site.

A) 4, 1, 3, 2, 5

B) 1, 3, 2, 4, 5

C) 2, 4, 5, 1, 3

D) 5, 4, 3, 2, 1

E) 4, 2, 1, 3, 5

Answer 18

E

Question 19

A scientist found two different sizes of a same protein obtained from plants and animals. This size difference in same type of protein doing identical function could be due to ___________________________

A) Glycosylation

B) Deletion of amino terminus

C)
Phosphorylation

D) Both A and B are possible

E) A, B and C are possible

Answer 19

D

Question 20

Which of the following is NOT involved in the elongation of a polypeptide during translation?

A) mRNA

B) Peptidyl tRNA

C) Amino acyl tRNA

D) Elongation factor

E) Initiation factor

Answer 20

E

Question 21

Which of the following is NOT true about prokaryotic operons?

A) RNA polymerase makes RNA only when needed.

B) Multiple genes could be transcribed from one operon.

C) Transcription and translation can occur simultaneously.

D) Introns are removed and exons are expressed from each operon.

E) Operator controls the expression of operon.

Answer 21

D

Question 22

The inducible operon regulates __________________________pathways and repressible operon regulates ______________________ pathways.

A) Glycolysis…….Krebs cycle

B) Substrate level……Oxidative phosphorylation

C) Anabolic…..Catabolic

D) Catabolic….Anabolic

E) Endergonic….Exergonic

Answer 22

D

Question 23

If there are abundant amounts of tryptophan, then the Trp operon will be __________.

A) completely inactive.

B) moderately active.

C) highly active.

D) regulated by lactose level.

E) regulated by the cAMP level.

Answer 23

A

Question 24

Which of the following will be the result if allolactose binds to the repressor?

A) It inactivates the operon and no genes are expressed.

B) mRNA exists for a specific time and then it is degraded before translation.

C) DNA binding protein will bind to promoter and stop the transcription.

D) Repressor is made inactive and transcription and translation occur.

E) DNA will be methylated and compacted by the repressor + allolactose.

Answer 24

D

Question 25

The role of a metabolite that controls a repressible operon is to

A) bind to the repressor protein and inactivate it.

B) bind to the operator region and block the attachment of RNA polymerase to the promoter

C) bind to promoter region and decrease the affinity of RNA polymerase for the promoter.

D) bind to the repressor protein and activate it.

E) increase the production of inactive repressor proteins.

Answer 25

D

Question 26

What happens if the operator is deleted from an inducible operon?

A) It will not be transcribed at all.

B) It will be transcribed only when lactose is present.

C) It will be transcribed at all times

D) It will be transcribed only when lactose is absent.

E) Without operator, promoter cannot function to make RNA.

Answer 26

C

Question 27

What happens if the promoter is deleted from an repressible operon?

A) It will not be transcribed at all.

B) It will be transcribed only when lactose is present.

C) It will be transcribed at all times

D) It will be transcribed only when lactose is absent.

E) Without operator, promoter cannot function to make RNA.

Answer 27

A

Question 28

Which of the following is an example of long-term transcriptional control of gene expression?

A) mRNA that is stored in the cytoplasm and needs a control signal to initiate translation

B) mRNA exists for a specific time before it is degraded

C) A zinc finger motif protein binds to a cis-acting element

D) RNA processing occurs before mRNA exits the nucleus

E) Chromosomal DNA is methylated and compacted

Answer 28

E

Question 29

Alternate splicing of mRNA is an example of ______________________ level of gene regulation in eukaryotes.

A) short-term transcriptional

B) long-term transcriptional

C) post-transcriptional

D) translational

E) post-translational

Answer 29

C

Question 30

Which of the following is an example of translational level control of gene expression?

A) DNA polymerase makes RNA only when needed

B) mRNA is degraded as soon as protein is made

C) protein is modified to become active

D) milk proteins are made by mammals only during lactation times

E) histones are acetylated to control gene expression

Answer 30

D

Question 31

Which of the following would happen if a transposable element inserts itself between the promoter and transcriptional start site of a structural gene?

A) Structural gene will be transcribed and translated along with the transposable element.

B) Transposable element will be transcribed and not the structural gene

C) Structural gene expression will not be affected at all

D) Both A and B are possible.

E) Both A, B and C are possible.

Answer 31

D

Question 32

Approximately, how many different ways the expression of RuBisCo may be regulated?

Answer 32

4

Question 33

A student in the lab is studying various genes when he mixes up two tubes. In order to not get in trouble with his professor, he needs to figure out which tube is which; he discovers that the gene in tube 1 makes an mRNA that codes for only one protein, and the gene in tube 2 makes an mRNA that codes for multiple proteins.

The student now knows which tube is which, and that the gene in tube 1 must come from a _________ because it is _________, and the gene in tube 2 must come from a _________ because it is _________?

A) Eukaryote, polycistronic, eukaryote, polycistronic

B) Prokaryote, polycistronic, eukaryote, monocistronic

C) Eukaryote, monocistronic, prokaryote, polycistronic

D) Prokaryote, monocistronic, prokaryote, monocistronic

Answer 33

C

Question 34

Some people are affected by Type I Diabetes, meaning they cannot produce insulin on their own. To treat this condition, a properly working insulin gene from humans is inserted into bacteria. In order to get E. coli to express human insulin, what modifications would be needed to be made to the DNA insert?

A) Removal of exons

B) Insertion of new splice sites

C) Removal of stop codon

D) Removal of introns

Answer 34

D

Question 35

Once the modifications are made to the DNA, it is then prepared to be combined with the vector. But first, the DNA must be cut in a way to allow for insertion. What enzyme cuts at specific sites in DNA, leaving sticky ends ready for ligation?

A) DNA Helicase

B) DNA Polymerase III

C) DNA exonuclease

D) Topoisomerase I

E) Restriction endonuclease

Answer 35

E

Question 36

To determine which bacteria contain the DNA vector with the human insulin, we used a vector containing the LacZ gene. The DNA insertion site is within this LacZ gene. If we use X-Gal (which becomes blue if Lacz is functional), How can we tell which colony contains plasmid ligated with the DNA insert?

A) The colonies that contain the insert will be blue

B) The colonies containing the insert will be smaller than those that did not

C) The colonies that contain the insert will be white or colorless.

D) The colonies with the inser will grow faster than the colonies with no insert

E) The colonies that contain the insert will only grown on X-Gal

Answer 36

C

Question 37

At the end of the DNA isolation and restriction digestion, you are separating the DNA fragments in agarose gel electrophoresis. The insert DNA encoding insulin is 1.4 kbp in length, while the vector DNA is 3.5 kbp in length. If you were to separate the two, where would you find them on the gel?

A) The insulin insert DNA would be closer to the cathode

B) The vector DNA would be closer to the cathode

C) Both would end up in the same place on the gel

D) Only radioactive DNA can be shown by this method

Answer 37

B

Question 38

What is one disease that should be treated or cured with biotechnology?

Answer 38

Diabetes