practice mcq

Question 1

Why are primers required for PCR?
a. Dna polymerase needs a fragment of double stranded DNA (primer bond to single stranded Dna)in order to start elongation of the second strand of DNA.
b. Primers synthesize second strand of DNA.
c. Primers are necessary to denature double-strand DNA into single-strand DNA.
d. DNA polymerase activity is blocked by the primers.

Answer 1

a. Dna polymerase needs a fragment of double stranded DNA (primer bond to single stranded Dna)in order to start elongation of the second strand of DNA.

Question 2

A variant of PCR In which two PCR reactions are carried out one after the other with
different pairs of primers are:
a. Multiplex
b. Nested-PCR
c. RT-PCR
d. Real-time PCR

Answer 2

b. Nested-PCR

Question 3

For DNA synthesis you do not need:
a. DNA polymerase
b. Ca 2+ ions
c. DNA matrix
d. Deoxyribonucleotide 5’-triphosphates

Answer 3

b. Ca 2+ ions

Question 4

Which stage in classic PCR is there to separate of double-strand DNA?
a. Elongation
b. Digestion
c. Denaturation
d. Annealing

Answer 4

c. Denaturation

Question 5

Which stage in classic PCR is there to extend the newly synthesized DNA strand?
a. Elongation
b. Digestion
c. Denaturation
d. Annealing

Answer 5

a. Elongation

Question 6

A nucleic acid sequencing method that uses dideoxynucleotides that stop the elongation of a polynucleotide chain in a PCR reaction is:
a. Maxam-Gilbert method.
b. Sanger method.
c. Pyrosequencing.
d. None of the mentioned.

Answer 6

b. Sanger method.

Question 7

Enzymatic sequencing using the Sanger method is based on:
a. The use of fluorescent markers.
b. Application of restriction enzymes.
c. Chain termination with dideoxynucleotides.
d. Chemical degradation of DNA

Answer 7

c. Chain termination with dideoxynucleotides.

Question 8

Which ingredient is NOT added to the reaction mixture in a sequencing method called
the Sanger method?
a. NTP
b. Dideoxynucleotides
c. Piperidine
d. Polymerase

Answer 8

c. Piperidine

Question 9

DGGE is a method which consists in:
a. Analysis of heteroduplexes after PCR.
b. Gel electrophoresis of the PCR product with a gradient of the denaturing agent.
c. Restriction fragment length polymorphism after restriction endonuclease cleavage of the PCR
product.
d. Single nucleotide polymorphisms detected by sequencing in a PCR product

Answer 9

b. Gel electrophoresis of the PCR product with a gradient of the denaturing agent.

Question 10

Which enzyme is not involved in pyrosequencing?
a. Sulfurylase.
b. Lucyferase.
c. Apyrase.
d. Restriction enzyme

Answer 10

d. Restriction enzyme

Question 11

“This method is based on nucleobase specific partiat chemical modification of DNA and subsequent cleavage of the DNA backbone at sites adjacent to the modified nucleotides. Chemical treatment generates breaks at a small proportion of one or two of the four nucleotide bases in each of four reactions (G, A+G, C, C+T).- - this fragment describes:
a. Maxam-Gilber sequencing.
b. Sanger sequencing.
c. Pyrosequencing.
d. RFLP.

Answer 11

a. Maxam-Gilber sequencing.

Question 12

Which of the following statements does not apply to comparative genome hybridization (CGH):
a. The aim of this technique is to quickly and efficiently compare two genomic DNA samples arising from two sources.
b. This is achieved through the use of competitive fluorescence in situ hybridization.
c. CGH is only able to detect unbalanced chromosomal abnormalities. This is because balanced chromosomal abnormalities do not affect copy number, which is what is detected by CGH
technologies.
d. CGH detects both balanced and unbalanced chromosomal abnormalities.

Answer 12

c. CGH is only able to detect unbalanced chromosomal abnormalities. This is because balanced chromosomal abnormalities do not affect copy number, which is what is detected by CGH technologies.

Question 13

Choose a sentence that describes the Southern blot method:
a. It is a method used in molecular biology for detection of a specific RNA sequence in DNA samples.
b. It is a method used in molecular biology for detection of a specific RNA sequence in RNA samples.
c. It is a method used in molecular biology for detection of a specific DNA sequence in DNA samples.
d. It is a method of separating PCR products in an agarose gel under the influence of an electric field.

Answer 13

c. It is a method used in molecular biology for detection of a specific DNA sequence in DNA samples.

Question 14

Isolating specific DNA sequences from many others and amplifying them in sufficient quantities for detailed analysis and manipulation is:
a. Transformation
b. Cloning
c. Transfection
d. Ligation

Answer 14

b. Cloning

Question 15

What is the B-galactosidase activity test?
a. On the determination of the activity of the B-galactosidase hydrolyzing compound
b. In measuring its concentration
c. On the use of Z-gal as a substrate, which is degraded to a white product
d. On using X-gal as a substrate, which is degraded to a blue product

Answer 15

d. On using X-gal as a substrate, which is degraded to a blue product

Question 16

The uptake of foreign DNA by eukaryotic cells is:
a. Transformation
b. Transduction
c. Transfection
d. Transversion

Answer 16

c. Transfection

Question 17

From the transfection methods listed below, determine which is transient:
a. Microinjection.
b. Liposome-mediated.
c. Transduction of Eukaryotic cells with viruses.
d. Gene gun

Answer 17

b. Liposome-mediated.

Question 18

Lipofection (one of the methods of eukaryotic cell transfection) consists of:
a. Shooting gold microspheres of coated DNA inside the cell.
b. The DNA solution is injected directly into the cell nucleus, or in the case of RNA into the cytoplasm, using a specially crafted glass capillary.
c. Use of liposomes and lipoplexes containing DNA or RNA.
d. Transfection using the short-term electric shock in a solution containing the nucleic acid.

Answer 18

c. Use of liposomes and lipoplexes containing DNA or RNA.

Question 19

The virus that infects and replicates within bacteria and archaea, usually capable of
infecting only one species, is:
a. Retroviruses
b. Adenoviruses
c. Bacteriophage
d. Lentiviruses

Answer 19

c. Bacteriophage

Question 20

Why should a plasmid have restriction sites as a good cloning vector?
a. It is needed for insertion of interested gene.
b. To duplicate the interested gene in replication process.
c. For selecting positive clones (those that took the plasmid).
d. This is not a necessary trait in a plasmid.

Answer 20

a. It is needed for insertion of interested gene.

Question 21

Why should a plasmid have antibiotic resistance gene as a good cloning vector?
a. It is needed for insertion of interested gene.
b. To duplicate the interested gene in replication process.
c. This is not a necessary trait in a plasmid.
d. For selecting positive clones (those that took the plasmid)

Answer 21

d. For selecting positive clones (those that took the plasmid)

Question 22

Which of the following cells is an example of unipotent stem cells?
a. Epidermis.
b. Zygote.
c. Marrow.
d. Blastocyst.

Answer 22

a. Epidermis.

Question 23

Indicate which of the following does not belong to the biomaterials used in regenerative medicine:
a. Synthetic or natural polymers.
b. Metallic implants.
c. Polyacrylamide gel.
d. Ceramics.

Answer 23

c. Polyacrylamide gel.

Question 24

Which of the following cells is an example of totipotent stem cells?
a. Epidermis.
b. Zygote.
c. Marrow.
d. Blastocyst.

Answer 24

b. Zygote.

Question 24

Choose which of the following shows the properties of the biomaterials: a. Mechanical properties of any biomaterial implant should should be different from native tissue. b. Metal implants should corrode in the human body. c. It should be flexible and hard to enable the formation of a 3D structure. d. It should be susceptible to the degradation under physiological conditions.

Answer 24

d. It should be susceptible to the degradation under physiological conditions.

Question 25

Among the following statements about GMOs, choose the one that is a myth. a. GM animals can be used in transplantology. b. GM plants can be used for obtain vaccines. c. GM animals can be used for obtain hormones such as insulin and growth hormone. d. GMOs are toxic for the environment.

Answer 25

d. GMOs are toxic for the environment.

Question 26

The primary meiotic arrest of the first order oocyte takes place in a. Diplotene prophase I. b. Anaphase I. c. Telophase Il. d. Metaphase II.

Answer 26

a. Diplotene prophase I.

Question 27

What event triggers the exit from the second meiotic arrest? a. Fertilization of the oocyte. b. Activation of the CSF factor. c. Inactivation of the APC complex. d. Decrease of the Ca2+ concentration.

Answer 27

a. Fertilization of the oocyte.

Question 28

Which of the following statements about proto-oncogenes is false? a. The mutant forms of proto-oncogenes are known as oncogenes. b. A proto-oncogene is a normal gene that could become an oncogene due to mutations or increased expression. c. A proto-oncogene is a gene that has the potential to cause cancer. d. Most oncogenes began as proto-oncogenes: normal genes involved in cell growth and proliferation or inhibition of apoptosis.

Answer 28

c. A proto-oncogene is a gene that has the potential to cause cancer.

Question 29

The levels of most of the mammalian cyclins fluctuate dramatically as cells progress through the cell cycle. Increased levels of which cyclin is observed in M cell cycle phase? a. E b. B c. A d. D1

Answer 29

b. B

Question 30

Choose a set of proteins involved in the Wnt pathway: a. Frizzled family receptor and LRP5/6, auxin, B-catenin, phosphoprotein Dishevelled (Dsh) b. Epidermal growth factor receptor (EGFR), docking protein GRB2, guanine nucleotide exchange factor SOS, MEK and mitogen-activated protein kinase (MAPK). c. R-SMAD, CO-SMAD, SARA, SMAD4. d. Patched-1 (PTCH1) receptor, Smoothened (SMO), oxysterols, GLI transcription factors.

Answer 30

a. Frizzled family receptor and LRP5/6, auxin, B-catenin, phosphoprotein Dishevelled (Dsh)

Question 31

Choose a set of proteins involved in the TGF-ß pathway: a. Frizzled family receptor and LRP5/6, auxin, B-catenin, phosphoprotein Dishevelled (Dsh). b. Epidermal growth factor receptor (EGFR), docking protein GRB2, guanine nucleotide exchange factor SOS, MEK and mitogen-activated protein kinase (MAPK). c. R-SMAD, Co-SMAD, SARA, SMAD4. d. Patched-1 (PTCH1) receptor, Smoothened (SMO), oxysterols, GLI transcription factors.

Answer 31

c. R-SMAD, Co-SMAD, SARA, SMAD4.

Question 32

EMT (epithelial-mesenchymal transition) is: a. The invasion of cancer cells through the basement membrane into a blood or lymphatic vessel. b. A process by which epithelial cells lose their cell polarity and cell-cell adhesion, and gain migratory and invasive properties to become mesenchymal stem cells. c. When cancer cells must escape from the lumina of these vessels and penetrate into the surrounding tissue. d. When a pathogenic agent's spread from an primary site to a secondary site within the hosts body

Answer 32

b. A process by which epithelial cells lose their cell polarity and cell-cell adhesion, and gain migratory and invasive properties to become mesenchymal stem cells.

Question 33

What is the function of histone H1? a. It is part of the nucleosome core b. Bends the structure of the solenoid c. Together with the H3 chromosome, it participates in the structure of centromeric nucleosome d. It is found only in the metaphase chromosome

Answer 33

b. Bends the structure of the solenoid

Question 34

The enzyme which adds a short segment of RNA, called an RNA primer on each DNA strand is: a. RNA helicase b. RNA primase c. DNA polymerase d. DNA ligase

Answer 34

b. RNA primase

Question 35

Name post-transcriptional events in eukaryotes, that must occur in order to form mature me: a. Addition of 3'cap, polyadenylation of 5'end, removal of introns by splicing b. Removal of 3'cap, polyadenylation of 5'end, addition of introns by splicing c. Addition of 5 cap, polyadenylation of 3'end, removal of exons by splicing d. Addition of 5'cap, polyadenylation of 3'end, removal of introns by splicing

Answer 35

d. Addition of 5'cap, polyadenylation of 3'end, removal of introns by splicing

Question 36

DNA molecule, virus, plasmid, artificial chromosome used to introduce foreign DNA into the a. Transformer b. Clone c. Vector d. Recombinant

Answer 36

c. Vector

Question 37

The introduction of DNA into a bacterial cell is called: a. Recombination b. Transposition c. Transfection d. Transformation

Answer 37

d. Transformation

Question 38

Isolating specific DNA sequences from many others and amplifying them in sufficient for detailed analysis and manipulation is: a. Transformation b. Cloning c. Transfection d. Ligation

Answer 38

b. Cloning

Question 39

Separation of molecules by antibody-affinity chromatography is based on: a. The size and shape of molecules. b. The charge of molecules. c. A biological specificity of molecules. d. The hydrophobicity of molecules.

Answer 39

c. A biological specificity of molecules.

Question 40

The probe used in the Western blot to detect specific protein is: a. Antibody. b. Fluorescent dye. c. Radioactively labeled probe. d. DNA fragment.

Answer 40

a. Antibody.

Question 41

Separation of molecules by gel filtration chromatography is based on: a. The charge of molecules. b. The size and shape of molecules. c. A biological specificity of molecules. d. The hydrophobicity of molecules.

Answer 41

b. The size and shape of molecules.

Question 42

Which of the following are pyrimidines found only in DNA: a. Adenine, guanine b. Cytosine, uracil c. Thymine, cytosine d. Adenine, cytosine

Answer 42

c. Thymine, cytosine

Question 43

A nucleotide consists of: a. Sugar and phosphate b. Sugar, base, phosphate c. Paired bases d. Sugar, base and three phosphates

Answer 43

b. Sugar, base, phosphate

Question 44

Griffith's experiment showed the existence of: a. Transformation phenomena in bacteria b. Transduction phenomena in bacteria c. Recombination phenomena in eukaryotic cells d. Nucleic acid

Answer 44

a. Transformation phenomena in bacteria

Question 45

Using the method of DNA isolation with the use of phenol and chloroform, in the organic phase we fir a. RNA and lipids b. DNA c. Proteins d. RNA and DNA

Answer 45

c. Proteins

Question 46

Northern blotting is used to analyze: a. DNA b. RNA c. Sugars d. Lipids

Answer 46

b. RNA

Question 47

What is NOT necessary for a PCR reaction? a. Thermocycler b. Knowledge of the sequence of the studied gene c. DNA strand denaturation d. Heat-stable DNA polymerase

Answer 47

b. Knowledge of the sequence of the studied gene

Question 48

Protein analysis methods do Not include: a. Mass spectroscopy b. In situ hybridization c. Western blotting d. Northern blotting

Answer 48

d. Northern blotting

Question 49

The chemical method for determining the amino acid sequence of proteins is: a. Sanger method b. Edman degradation c. Maxam degradation d. Mass spectrometry

Answer 49

b. Edman degradation

Question 50

Which method is used to indicate the thermodynamic stability of proteins? a. NMR b. Circular dichroism c. X-ray diffraction d. Mass spectrometry

Answer 50

b. Circular dichroism

Question 51

What is the name of a type of liquid column chromatography using a high pressure eluent? a. TLC b. HPLC c. DGGE d. GPC

Answer 51

b. HPLC

Question 52

Which stage classic PCR doesn't contain: a. Denaturation b. Annealing c. Restriction. d. Elongation.

Answer 52

c. Restriction.

Question 53

The necessary ingredients in the classic PCR mix aren't: a. Thermostable polymerase. b. Ligation enzymes. c. dNTPs. d. Primers.

Answer 53

b. Ligation enzymes.

Question 54

RFLP is a technique that exploits variations in homologous DNA sequences, known as polymorphisms detected through use of: a. Restriction enzymes. b. SYBR Green. c. Reverse transcriptase. d. Fluorescently labeled probes

Answer 54

a. Restriction enzymes.

Question 55

Equilibrium sedimentation allows protein separation according to: a. Their electric charge. b. Their shape c. Their density. d. Their size

Answer 55

C. Their density.

Question 56

Select the sentence describing the indirect ELISA method. a. Is a two-step ELISA which involves two binding process of primary antibody and labeled secondary antibody (to each other). b. An antigen or sample is immobilized directly on the plate and a conjugated detection antibody binds to the target protein. Substrate is then added, producing a signal that is proportional to the amount of analyte in the sample. c. Two specific antibodies are used to capture the antigen between them, commonly referred to as matched antibody pairs d. It is based on the competition between the studied proteins and the labeled antibody. Unlike other methods, the intensity of the enzymatic reaction will be inversely proportional to the concentration of the tested proteins, because the higher their concentration, the less labeled antibody will bind to the antigen placed on the solid phase

Answer 56

a. Is a two-step ELISA which involves two binding process of primary antibody and labeled secondary antibody (to each other).

Question 57

It is a system of recognizing and repairing erroneous insertion, deletion, and mixincorporation of bases that can arise during DNA replication and recombination as well as repairing some forms of DNA damages - this fragment describes a. Mismatched repair (MMR) b. Homologous recombination (HR) c. Base excision repair (BER) d. Nucleotide excision repair (NER)

Answer 57

a. Mismatched repair (MMR)

Question 58

Which of the following steps do not occur in western blot a. Gel electrophoresis b. Transfer from gel to nitrocellulose membrane c. Sequencing d. Incubation with antibody

Answer 58

c. Sequencing

Question 59

The absorption ratio at wavelength 260 to 280(A260/A280) in the qualitative and quantitative analysis of DNA with the spectrophotometer is 3.24 means: a. Contamination with DNA b. Contamination with proteins c. Contamination with phenol d. Contamination with RNA

Answer 59

D. Contamination with RNA