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  • Question 1 - The process by which DNA fragments are separated by gel and transferred onto...

    Correct

    • The process by which DNA fragments are separated by gel and transferred onto a membrane sheet is called:

      Your Answer: Southern blotting

      Explanation:

      A Southern blot is a method used in molecular biology for detection of a specific DNA sequence in DNA samples. Southern blotting combines transfer of electrophoresis-separated DNA fragments to a filter membrane and subsequent fragment detection by probe hybridization. The other forms of blotting involve the use of RNA and proteins.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      36.9
      Seconds

  • Question 2 - The telomerase is capable of adding several more repeats of telomeres at which...

    Correct

    • The telomerase is capable of adding several more repeats of telomeres at which end of the guanosine rich region.

      Your Answer: 3rd end

      Explanation:

      Telomerase is a reverse transcriptase that uses the RNA template to synthesize DNA in the 5th-3rd direction resulting in extension of the 3rd end and then translocates it to the newly synthesized end. The GT rich strand is thus elongated.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      6
      Seconds

  • Question 3 - Carcinogens found in cigarette smoke can transform proto-oncogenes to oncogenes through: ...

    Correct

    • Carcinogens found in cigarette smoke can transform proto-oncogenes to oncogenes through:

      Your Answer: Point mutations in genomic DNA

      Explanation:

      80% of the pancreatic cancers are environmentally influenced by smoking which increases the risk by 50%. Mutation can occur in the KRAS, p16, SMAD4, and TP53 genes among other tumour suppression genes. Smoking can be implicated in transformation of all these genes. Apart from KRAS all the genes are inactivated in pancreatic cancer. As KRAS is the most commonly altered gene, mutation occurs as point mutation. As smoking is the most common aetiology in pancreatic cancer, and KRAS is the most important gene that is altered. Most commonly cigarette smoke causes point mutation.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      11
      Seconds

  • Question 4 - In a knockout mouse model the process used to combine the new DNA...

    Correct

    • In a knockout mouse model the process used to combine the new DNA sequence and the stem cells is known as:

      Your Answer: Insertion

      Explanation:

      Chimerisation is also known as the formation of recombinant DNA. When a foreign DNA sequence is inserted into a plasmid or other DNA sequence, this process is known as insertion.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      12.4
      Seconds

  • Question 5 - Regarding Polymerase Chain Reaction, all are true except: ...

    Correct

    • Regarding Polymerase Chain Reaction, all are true except:

      Your Answer: There is a linear rise of DNA copies during amplification.

      Explanation:

      All are true except there is a linear rise of DNA copies during amplification. There is an exponential rise in amplification of DNA.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      8.2
      Seconds

  • Question 6 - Which of the following is an incorrect statement regarding the structure of DNA?...

    Correct

    • Which of the following is an incorrect statement regarding the structure of DNA?

      Your Answer: The two strands of DNA are held together by cysteine bonds.

      Explanation:

      The two strands of DNA are held together by hydrogen bonds formed between the nucleotide bases.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      15.3
      Seconds

  • Question 7 - The enzyme responsible for telomeres maintaining their length after cell division is called:...

    Correct

    • The enzyme responsible for telomeres maintaining their length after cell division is called:

      Your Answer: Telomerase

      Explanation:

      Telomerase is the enzyme responsible for maintenance of the length of telomeres by addition of guanine-rich repetitive sequences. Telomerase activity is exhibited in gametes and stem and tumor cells.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      7.6
      Seconds

  • Question 8 - During which phase of the cell cycle does DNA synthesis occur? ...

    Correct

    • During which phase of the cell cycle does DNA synthesis occur?

      Your Answer: S

      Explanation:

      DNA synthesis occurs in the S phase of the cell cycle. In the G1 phase the cell prepares to divide. In G2 the cellular organelles divide and in the M phase mitosis occur. In the G0 phase the cell becomes quiescent and does not divide further

    • This question is part of the following fields:

      • Genetics
      • Medicine
      4.3
      Seconds

  • Question 9 - In DNA cloning and sequencing, the bases in nucleotides chains are bound together...

    Correct

    • In DNA cloning and sequencing, the bases in nucleotides chains are bound together by:

      Your Answer: Hydrogen bonding.

      Explanation:

      Nucleotides will always bind together via hydrogen bonds. There are two hydrogen bonds present between thymine and adenine and three hydrogen bonds present between guanine and cytosine.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      11.5
      Seconds

  • Question 10 - Restriction Enzymes... ...

    Correct

    • Restriction Enzymes...

      Your Answer: Cut DNA sequences at specific sites

      Explanation:

      Restriction endonucleases are enzymes that recognise short sequences of double stranded DNA and cut them at specific nucleotide points or sequences. These sequences differ for different restriction endonucleases.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      4.4
      Seconds

  • Question 11 - Which of the following is not true regarding mitochondrial chromosome disorders? ...

    Correct

    • Which of the following is not true regarding mitochondrial chromosome disorders?

      Your Answer: Because mitochondrial chromosomes have no introns in their genes, any point mutation has a low likelihood of having an effect.

      Explanation:

      Mitochondrial DNA (mtDNA) does indeed lack introns, meaning that its genes are closely packed with coding sequences. This actually means that any point mutation in the mtDNA is more likely to have an effect, not less. The lack of introns means there are fewer non-coding regions where mutations can occur without affecting gene function. Thus, mutations in mtDNA often have significant consequences because they are more likely to alter essential coding sequences.

      The other statements are true:

      • Most mitochondrial diseases are myopathies and neuropathies with a maternal pattern of inheritance: This is correct because mtDNA is inherited maternally, and many mitochondrial disorders affect muscle and nerve function.
      • Retinal degeneration, diabetes mellitus, and some forms of hearing loss are some of the other diseases attributed to mitochondrial chromosome defects: These are indeed conditions associated with mitochondrial defects.
      • Mitochondrial chromosome defects are inherited from one’s mother: This is correct, as mtDNA is passed from mother to offspring.
      • Leber’s hereditary optic neuropathy (LHON), the commonest cause of blindness in young men, is an example of a mitochondrial chromosome defect: This is true; LHON is a well-known mitochondrial disorder.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      9.6
      Seconds

  • Question 12 - With regard to X-linked disorders which of the following are true: ...

    Correct

    • With regard to X-linked disorders which of the following are true:

      Your Answer: X linked recessive disorders usually present in males and only very rarely present in homozygous females

      Explanation:

      X linked disorders are more common in males as they only need one mutated copy of the X chromosome to manifest the disease with full severity while the females need two X chromosomes to manifest the disease, even with one defected X chromosome the severity is less than that seen in males.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      31.3
      Seconds

  • Question 13 - During which phase are the 2 chromatids pulled apart at the centromere? ...

    Correct

    • During which phase are the 2 chromatids pulled apart at the centromere?

      Your Answer: Anaphase

      Explanation:

      During the prometaphase the microtubule organizing centre completely develops. The spindle fibers attach to the chromosome and the centriole. It is in the Anaphase however that the spindle fibers contract pulling the sister chromatids apart. Later in the anaphase a cleave furrow beings to forms.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      36
      Seconds

  • Question 14 - Which statement is correct? ...

    Correct

    • Which statement is correct?

      Your Answer: MtDNA principally encodes for proteins that are involved in oxidative phosphorylation for the production of ATP in the cell.

      Explanation:

      Mitochondria have no nucleus instead they contain their own free floating circular genome (MtDNA), which encodes 13 different subunits of proteins involved in oxidative phosphorylation. The remainder of the mitochondrial proteins are nuclear encoded, synthesized in the cytoplasm, and transported into the mitochondria.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      15.2
      Seconds

  • Question 15 - In RFLP (restriction fragment length polymorphism), the DNA fragments are separated by length...

    Correct

    • In RFLP (restriction fragment length polymorphism), the DNA fragments are separated by length through a process known as:

      Your Answer: Agarose gel electrophoresis

      Explanation:

      Samples of DNA from individuals are broken into pieces by restriction enzymes and the fragments are separated according to their lengths via gel electrophoresis. Although now largely obsolete due to the rise of inexpensive DNA sequencing technologies, RFLP analysis was the first DNA profiling technique inexpensive enough to see widespread application.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      7.7
      Seconds

  • Question 16 - Which of the following is true for P 53: ...

    Correct

    • Which of the following is true for P 53:

      Your Answer: It is induced by ‘broken’ DNA

      Explanation:

      All of the above mentioned statements are true regarding tumour suppressor genes.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      4.3
      Seconds

  • Question 17 - The length of DNA is generally measured in terms of number of: ...

    Correct

    • The length of DNA is generally measured in terms of number of:

      Your Answer: Base pairs

      Explanation:

      As DNA is made up of nucleotides, its length is measured by the number of base pairs in the DNA molecules.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      102.4
      Seconds

  • Question 18 - Immortality can result from over expression of which enzyme? ...

    Correct

    • Immortality can result from over expression of which enzyme?

      Your Answer: Telomerase

      Explanation:

      Telomerase activity is seen in germ cells and is absent in somatic cells. Telomeres prevent the chromosomes from shortening and prevent the coding portion of the DNA from being lost, thus allowing the cell to replicate indefinitely.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      3.7
      Seconds

  • Question 19 - Three adjacent nucleotides code for a particular amino acid. These are called codons....

    Correct

    • Three adjacent nucleotides code for a particular amino acid. These are called codons. How many common amino acids are there and how many potential codon combinations make up the genetic code?

      Your Answer: 20 amino acids, 64 codon combinations

      Explanation:

      There are around 20 amino acids and 61 out of the 64 combinations of codon code for these 20 common amino acids.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      2.9
      Seconds

  • Question 20 - In most somatic cells telomeres progressively shorten as: ...

    Correct

    • In most somatic cells telomeres progressively shorten as:

      Your Answer: The cell divides

      Explanation:

      Telomerase activity is seen in germ cells and is absent in somatic cells. A somatic cell is any biological cell forming the body of an organism, other than a gamete, germ cell, gametocyte or undifferentiated stem cell. i.e. liver cells. Telomeres prevent the chromosomes from shortening and prevent the coding portion of the DNA from being lost, thus allowing the cell to replicate indefinitely. During replication telomeres may be lost resulting in cell death.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      4.8
      Seconds

  • Question 21 - Regarding DNA cloning and sequencing, all of the following are true, except: ...

    Correct

    • Regarding DNA cloning and sequencing, all of the following are true, except:

      Your Answer: Yeast artificial chromosomes ( yacs) are vectors

      Explanation:

      Yeast chromosomes cannot be used as a vector. All the rest are true. Vectors can be bacteria, viruses and plasmids. DNA ligase binds the DNA fragment to the host DNA after insertion. Fluorescence can be used to visualize them.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      4.9
      Seconds

  • Question 22 - Which part of the chromosome plays a role in preserving its integrity and...

    Correct

    • Which part of the chromosome plays a role in preserving its integrity and stability?

      Your Answer: Telomere

      Explanation:

      Telomeres are non coding DNA plus proteins that are found at the end of the linear chromosomes. They maintain the integrity of the chromosomes and prevent their shortening

    • This question is part of the following fields:

      • Genetics
      • Medicine
      14.5
      Seconds

  • Question 23 - Which of the following statements is true about chromosomes? ...

    Correct

    • Which of the following statements is true about chromosomes?

      Your Answer: All of the above

      Explanation:

      All of the above mentioned statements are true regarding chromosomes.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      10.3
      Seconds

  • Question 24 - Which of the following with regard to autosomal dominant disorders are true: ...

    Correct

    • Which of the following with regard to autosomal dominant disorders are true:

      Your Answer: The offspring of a heterozygous individual has a 50% chance of inheriting the chromosome carrying the disease allele

      Explanation:

      50% of the children will be effected from parents who are heterozygous for an autosomal dominant disorder. An allele can be dominant or recessive. Individuals, meanwhile, can be homozygous or heterozygous: individuals who are homozygous for a certain gene carry two copies of the same allele. individuals who are heterozygous for a certain gene carry two different alleles.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      42
      Seconds

  • Question 25 - Male to male transmission is a key factor of which type of inheritance?...

    Correct

    • Male to male transmission is a key factor of which type of inheritance?

      Your Answer: Autosomal dominant

      Explanation:

      Autosomal dominant type of inheritance can include both sexes in the same ratio. There is no skipping a generation and father to son transmission is common. The passing of the trait is sex independent.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      6.3
      Seconds

  • Question 26 - Defects in chromosomal structure (and examples) include those mentioned below except: ...

    Correct

    • Defects in chromosomal structure (and examples) include those mentioned below except:

      Your Answer: Lyonization (x-linked disorders)

      Explanation:

      All are true except for A) Lyonization which is the inactivation of the X chromosomes in a female. It is not a chromosomal abnormality.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      6.8
      Seconds

  • Question 27 - With regard to X linked disorders which of the following are true ...

    Correct

    • With regard to X linked disorders which of the following are true

      Your Answer: X linked recessive disorders usually present in males and only very rarely present in homozygous females

      Explanation:

      All are true for autosomal recessive disorders. Dominance rules for sex-linked gene loci are determined by their behaviour in the female: because the male has only one allele (except in the case of certain types of Y chromosome aneuploidy), that allele is always expressed regardless of whether it is dominant or recessive.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      5.5
      Seconds

  • Question 28 - When 2 nucleotide chains of DNA bind together, thymine is bound to: ...

    Correct

    • When 2 nucleotide chains of DNA bind together, thymine is bound to:

      Your Answer: Adenine

      Explanation:

      As a general rule in the structure of DNA, thymine always binds to adenine with two hydrogen bonds, cytosine always binds to guanine with three hydrogen bonds and vice versa. However In the structure of RNA the only difference is that adenine binds to uracil instead of thymine. But thymine will always bind to adenine.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      8.4
      Seconds

  • Question 29 - The process whereby DNA fragments are separated by size and charge is called:...

    Correct

    • The process whereby DNA fragments are separated by size and charge is called:

      Your Answer: Gel electrophoresis

      Explanation:

      Fragments of DNA of varying length can be separated on the basis of their charge and their size by a process called gel electrophoresis. Because DNA contains negatively charged phosphate groups, it will migrate in an electric field toward the positive electrode. Shorter chains migrate more rapidly through the pores of the gel, and thus separation depends on length. DNA bands in the gel can be visualized by various techniques including staining with dyes and autoradiography.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      6.7
      Seconds

  • Question 30 - Critical shortening of Telomeres result in: ...

    Correct

    • Critical shortening of Telomeres result in:

      Your Answer: Activation of p53 and prb and cell crisis

      Explanation:

      Telomeres are repetitive nucleotide sequences at the ends of chromosomes that protect them from deterioration or from fusion with neighboring chromosomes. Each time a cell divides, its telomeres shorten. When they become critically short, they can no longer protect the chromosome ends, triggering a DNA damage response.

      This response leads to the activation of tumor suppressor proteins p53 and pRb (retinoblastoma protein). Activated p53 can induce cell cycle arrest, allowing time for DNA repair or triggering apoptosis if the damage is irreparable. Similarly, pRb helps regulate cell cycle progression and can halt the cell cycle to prevent the proliferation of cells with damaged DNA.

      As a result, the cell enters a state of crisis, characterized by widespread cell death and genomic instability, which ultimately prevents the propagation of cells with critically shortened telomeres.

      Therefore, the correct answer is:

      Activation of p53 and pRb and cell crisis

    • This question is part of the following fields:

      • Genetics
      • Medicine
      3.8
      Seconds

  • Question 31 - Near the transcription site of a gene, the site at which RNA polymerase...

    Correct

    • Near the transcription site of a gene, the site at which RNA polymerase and its cofactors bind is known as the:

      Your Answer: Promotor

      Explanation:

      Transcription will begin when the RNA polymerase II binds to the promotor. The promotor is a sequence of 25 nucleotides found upstream from the start site of transcription. This promotor sequence is known as the TATA box. Transcription factors also bond along with RNA polymerase to this site to form a complex. However some may bind to regulatory elements proximal to the promotor site.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      6.6
      Seconds

  • Question 32 - Southern Blotting and DNA probes: ...

    Correct

    • Southern Blotting and DNA probes:

      Your Answer: DNA fragments are separated by gel electrophoresis and transferred onto membrane sheets in southern blotting

      Explanation:

      A Southern blot is a method used in molecular biology for detection of a specific DNA sequence in DNA samples. Southern blotting combines transfer of electrophoresis-separated DNA fragments to a filter membrane and subsequent fragment detection by probe hybridization. The other forms of blotting involve the use of RNA and proteins.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      7.9
      Seconds

  • Question 33 - The length of DNA is generally measured in terms of the number of:...

    Correct

    • The length of DNA is generally measured in terms of the number of:

      Your Answer: Base pairs

      Explanation:

      As DNA is made up of nucleotides, its length is measured by the number of base pairs in the DNA molecules.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      3.9
      Seconds

  • Question 34 - The mitochondrial chromosome is a circular DNA molecule. They encode for proteins needed...

    Correct

    • The mitochondrial chromosome is a circular DNA molecule. They encode for proteins needed for ATP production. These proteins are also essential for:

      Your Answer: Apoptotic cell death

      Explanation:

      The intrinsic pathway or the mitochondrial pathway of apoptosis is activated due to the loss of BCL-2 and other antiapoptotic proteins. This loss results in the increased membrane permeability and release of cytochrome C which activates caspases downstream resulting in apoptosis.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      9
      Seconds

  • Question 35 - The process by which RNA fragments are separated by gel electrophoresis and transferred...

    Incorrect

    • The process by which RNA fragments are separated by gel electrophoresis and transferred onto a membrane sheet is called:

      Your Answer: Southern blotting

      Correct Answer: Northern blotting

      Explanation:

      Blots of the gel can be made from using nitrocellulose paper. Northern blots are produced when a fragment of radioactive DNA hybridize with RNA on a nitrocellulose blot of a gel and southern blots are produced when DNA hybrize with DNA on a nitrocellulose blot of the gel.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      12.7
      Seconds

  • Question 36 - The chromosomes that principally encode for proteins or RNA molecules involved in mitochondrial...

    Correct

    • The chromosomes that principally encode for proteins or RNA molecules involved in mitochondrial function are found:

      Your Answer: In the nucleus of each diploid cell

      Explanation:

      While mitochondria have their own small circular DNA (mtDNA) that encodes some of the proteins and RNAs required for mitochondrial function, the majority of proteins involved in mitochondrial function are encoded by nuclear DNA. These nuclear genes are transcribed in the nucleus and then translated into proteins in the cytoplasm. The proteins are subsequently imported into the mitochondria.

      Therefore, the correct answer is:

      • In the nucleus of each diploid cell

    • This question is part of the following fields:

      • Genetics
      • Medicine
      83.2
      Seconds

  • Question 37 - “Ploidy” is a term used to refer to the number of chromosomes in...

    Correct

    • “Ploidy” is a term used to refer to the number of chromosomes in cells. Cancer cells are commonly:

      Your Answer: Aneuploidy

      Explanation:

      Cancer cells most commonly undergo disordered cell growth and cell division. This results in an additional number of chromosomes called aneuploidy. This is a characteristic of cancer cells along with variation in differentiation of the cells.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      4.3
      Seconds

  • Question 38 - Under normal conditions (where n represents the number of chromosome pairs), just before...

    Correct

    • Under normal conditions (where n represents the number of chromosome pairs), just before mitosis begins, how many chromosomes are contained in the nucleus of each somatic cell:

      Your Answer: 4n

      Explanation:

      In a normal somatic cell there are 2n chromosome but in a replicating cell just before mitosis the chromosomes duplicate but are still joined via the centrosome. Thus there are 4n chromosomes. After completion of mitosis the number goes back to 2n.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      45.1
      Seconds

  • Question 39 - Which statement is correct regarding mRNA? ...

    Correct

    • Which statement is correct regarding mRNA?

      Your Answer: mRNAs are mainly found in the nucleus and cytoplasm of a cell.

      Explanation:

      mRNA is transcribed from DNA and is carried to the cytosol to be translated. Hence it is mainly found in the cytosol and the nucleus of a cell. It is single stranded and contains the base uracil instead of thymine.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      13
      Seconds

  • Question 40 - Normal parents have a child with a recessive condition, Tay Sachs. The chance...

    Correct

    • Normal parents have a child with a recessive condition, Tay Sachs. The chance of them having a normal child is?

      Your Answer: 75%

      Explanation:

      The chance for normal parents having a child with a recessive disease is 1:4 or 25%. As both the parents are heterozygous for this condition. They have a 3:4 chance of having a normal child or 75%.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      5
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Genetics (39/40) 98%
Medicine (39/40) 98%
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