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  • Question 1 - Telomerase is active in all of the following cells, except: ...

    Correct

    • Telomerase is active in all of the following cells, except:

      Your Answer: Certain liver cells

      Explanation:

      Telomerase is an enzyme that adds repetitive nucleotide sequences to the ends of chromosomes (telomeres), preventing their shortening during cell division. Telomerase activity is crucial for cells that divide frequently and need to maintain their telomere length for continued proliferation. These include:

      • Stem cells: They have high telomerase activity to maintain their long-term proliferative capacity.
      • Germ cells: These cells also have active telomerase to ensure the stability of genetic material across generations.
      • Certain white blood cells: Some immune cells, particularly those that need to proliferate in response to infection, show telomerase activity.
      • Certain cancer cells: Many cancer cells reactivate telomerase, which contributes to their uncontrolled growth and immortality.

      However, most somatic cells, including certain liver cells, do not exhibit significant telomerase activity. While some liver cells might show low levels of telomerase activity during regeneration, it is not generally active in normal, differentiated liver cells.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      15.3
      Seconds

  • Question 2 - Regarding Gene Knockout Mouse Models, all are true except: ...

    Incorrect

    • Regarding Gene Knockout Mouse Models, all are true except:

      Your Answer: Knockout models are important in studying roles of sequenced genes with unknown function

      Correct Answer: In knockout mouse models a gene is turned on through targeted mutation

      Explanation:

      In knockout mouse models, a gene is not turned on but rather turned off or “knocked out” through targeted mutation. This involves disrupting or deleting the gene to study the effects of its loss of function. Knockout models are crucial for understanding the roles of specific genes, particularly those with unknown functions.

      The other statements are true:

      • Knockout models are important in studying the roles of sequenced genes with unknown function.
      • RFLP (Restriction Fragment Length Polymorphisms) can be subcategorized as SLP (single locus probe) and MLP (multi locus probe).
      • RFLP analysis is slow and cumbersome and is now largely obsolete, having been replaced by more efficient techniques.
      • Sequence changes involved in RFLP can be analyzed more quickly by PCR (Polymerase Chain Reaction).

    • This question is part of the following fields:

      • Genetics
      • Medicine
      15.3
      Seconds

  • Question 3 - Which of the following statements is not true about mitochondrial chromosomes? ...

    Correct

    • Which of the following statements is not true about mitochondrial chromosomes?

      Your Answer: Mitochondrial chromosomes play no role in the transmission of disease from generation to generation.

      Explanation:

      All the above mentioned statements are true except that mitochondrial DNA is passed from the mother to the child. If the child inherits the defective mitochondrial gene it will manifest some form of the disease. Commonly inherited diseases related to mitochondrial abnormality are Leber hereditary optic neuropathy and myoclonic epilepsy with ragged red fibers (MERRF).

    • This question is part of the following fields:

      • Genetics
      • Medicine
      17.3
      Seconds

  • Question 4 - Immortality can result from over expression of which enzyme? ...

    Incorrect

    • Immortality can result from over expression of which enzyme?

      Your Answer: None of the above

      Correct 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
      46.8
      Seconds

  • Question 5 - Which of the following is an incorrect statement regarding the structure of DNA?...

    Incorrect

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

      Your Answer: There are only four possible pairs of nucleotides.(ta, at, gc and cg)

      Correct 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
      53.2
      Seconds

  • Question 6 - Which of the following is false with regard to the following statement: Proto-...

    Correct

    • Which of the following is false with regard to the following statement: Proto- oncogenes can be transformed to oncogenes in the following ways.

      Your Answer: Inhibition of P53

      Explanation:

      Proto oncogenes cannot be transformed into oncogenes due to inhibition of P53 gene. There has to be a mutation in the proto oncogene. All the other options are true.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      21.8
      Seconds

  • Question 7 - 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
      17.9
      Seconds

  • Question 8 - Which of the following are true when it comes to tumour suppressor genes:...

    Incorrect

    • Which of the following are true when it comes to tumour suppressor genes:

      Your Answer: Viruses can inactivate tumour suppressor genes

      Correct Answer: All of the options are true

      Explanation:

      All of the above mentioned statements are true regarding tumour suppressor genes. Tumour suppressor genes generally follow the two-hit hypothesis, which implies that both alleles that code for a particular protein must be affected before an effect is manifested.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      5.9
      Seconds

  • Question 9 - Which of the following is true for P53: ...

    Correct

    • Which of the following is true for P53:

      Your Answer: It is induced by ‘broken’ DNA

      Explanation:

      P53 gene is activated as a result of damaged DNA and if that cannot be repaired then it activates apoptosis.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      5.9
      Seconds

  • Question 10 - 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
      28.3
      Seconds

  • Question 11 - What is the structure of nucleosomes? ...

    Incorrect

    • What is the structure of nucleosomes?

      Your Answer: Strands of double strand DNA + introns + exons

      Correct Answer: Strands of double strand DNA + histones

      Explanation:

      DNA is packed and condensed by binding to histone proteins. The double stranded DNA forms a complex with histone proteins which is called a nucleosome. There are 8 histone proteins contained in one core of nucleosome.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      7.5
      Seconds

  • Question 12 - Telomeres are best described as: ...

    Incorrect

    • Telomeres are best described as:

      Your Answer: The protein end portion of DNA protecting the DNA from damage

      Correct Answer: A repetitive DNA sequence at the end of a DNA molecule.

      Explanation:

      Telomeres are non-coding DNA consisting of repetitive nucleotide sequences 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
      30.8
      Seconds

  • Question 13 - Regarding Polymerase Chain Reaction, all are true except: ...

    Incorrect

    • Regarding Polymerase Chain Reaction, all are true except:

      Your Answer: DNA is initially denatured by heat into single stranded DNA prior to cooling

      Correct 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
      18.8
      Seconds

  • Question 14 - The process of DNA amplification and quantification is called: ...

    Correct

    • The process of DNA amplification and quantification is called:

      Your Answer: PCR

      Explanation:

      PCR/polymerase chain reaction is a procedure carried out in a test tube that can be used on the smallest amount of DNA to amplify it, allowing for millions of copies of specific nucleotides to be made.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      8.9
      Seconds

  • Question 15 - 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
      7
      Seconds

  • Question 16 - At the end of which phase will P53 halt the cell cycle? ...

    Correct

    • At the end of which phase will P53 halt the cell cycle?

      Your Answer: G1 phase

      Explanation:

      P53 regulates the cell cycle. It regulates the progression from G1 to S phase

    • This question is part of the following fields:

      • Genetics
      • Medicine
      8
      Seconds

  • Question 17 - Regarding restriction fragment length polymorphisms (RFLP) and Gene Knockout Mouse Models. All are...

    Correct

    • Regarding restriction fragment length polymorphisms (RFLP) and Gene Knockout Mouse Models. All are true except:

      Your Answer: In knockout mouse models a gene is turned on through targeted mutation

      Explanation:

      In RFLP, polymorphism occurs in 98% of the non coding genome, resulting in no phenotypical change in the organism. A gene is not turned on by a mutation, rather the mutation at the restriction site will alter the DNA and the DNA will now form fragments of different lengths. PCR is a better technique than RFLP.

      A knockout, as related to genomics, refers to the use of genetic engineering to inactivate or remove one or more specific genes from an organism. Scientists create knockout organisms to study the impact of removing a gene from an organism, which often allows them to then learn something about that gene’s function.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      79.8
      Seconds

  • Question 18 - The enzyme responsible for Telomeres to maintain their length after cell division is...

    Correct

    • The enzyme responsible for Telomeres to maintain their length after cell division is called:

      Your Answer: Telomerase reverse transcriptase

      Explanation:

      Telomeres are non-coding DNA consisting of repetitive nucleotide sequences 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
      20.5
      Seconds

  • Question 19 - 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
      3.3
      Seconds

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

    Incorrect

    • In most somatic cells telomeres progressively shorten as:

      Your Answer: The host ages

      Correct Answer: The cell divides

      Explanation:

      Telomere length shortens with age. Progressive shortening of telomeres leads to senescence, apoptosis, or oncogenic transformation of somatic cells, affecting the health and lifespan of an individual. 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
      6.8
      Seconds

  • Question 21 - When one of the two copies of the autosomes has a mutation and...

    Incorrect

    • When one of the two copies of the autosomes has a mutation and the protein produced by the normal form of the gene cannot compensate. The affected individual has an:

      Your Answer: Autosomal recessive disorder

      Correct Answer: Autosomal dominant disorder

      Explanation:

      An autosomal dominant trait will be expressed no matter the consequence. If one chromosome has a mutation the other will not be able to compensate for the mutation hence the protein formed will be mutated and will not function properly.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      30.3
      Seconds

  • Question 22 - Which of the following with regard to DNA mutations does not fit: ...

    Correct

    • Which of the following with regard to DNA mutations does not fit:

      Your Answer: All gene mutations cause clinical disease entities

      Explanation:

      All gene mutations do not cause a clinical manifestation of the disease, some gene mutations are silent mutations. They are present but do not cause any disease.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      26.9
      Seconds

  • Question 23 - Which statement about X linked dominant disorders is FALSE? ...

    Incorrect

    • Which statement about X linked dominant disorders is FALSE?

      Your Answer: All the female offspring of an affected man will have the disease.

      Correct Answer: Heterozygous females tend to have the disease more severely than affected males.

      Explanation:

      Women who have the affected X chromosome will be affected, but the severity will be less than that in males as they have a normal X chromosome to counter the effect of the mutated X chromosome. Affected males will pass on the defect to their daughters 100% of the time but not to their sons.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      32.2
      Seconds

  • Question 24 - 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
      11.8
      Seconds

  • Question 25 - Mutation in RB can lead to the formation of which cancer? ...

    Incorrect

    • Mutation in RB can lead to the formation of which cancer?

      Your Answer: Breast cancer

      Correct Answer: Retinoblastoma

      Explanation:

      Patients with a history of autosomal dominant familial retinoblastoma have at least one mutated copy of the RB gene. This predisposes the patient to develop retinoblastoma in one or both the eyes. Patients with a family history should be screened properly so that it can be detected and treated as early as possible.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      12.4
      Seconds

  • Question 26 - Which of the following conditions results from chromosomal ‘non-disjunction’? ...

    Correct

    • Which of the following conditions results from chromosomal ‘non-disjunction’?

      Your Answer: All of the options

      Explanation:

      Non-disjunction can result in aneuploidy i.e. abnormal number of chromosomes in a cell. It results due to uneven division of chromosomes in the meiosis 1 or 2 phase. All the above mentioned examples are of non-disjunction.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      12.5
      Seconds

  • Question 27 - Southern Blotting and DNA probes: ...

    Incorrect

    • Southern Blotting and DNA probes:

      Your Answer: Localisation of native nucleic acid sequences within cells is part of insitu hybridisation

      Correct 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
      16.5
      Seconds

  • Question 28 - In a knockout mouse model the process used to combine the new DNA...

    Incorrect

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

      Your Answer: Chimerisation

      Correct 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
      9.1
      Seconds

  • Question 29 - 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
      4.5
      Seconds

  • Question 30 - Which statement is incorrect regarding transcription of DNA? ...

    Incorrect

    • Which statement is incorrect regarding transcription of DNA?

      Your Answer: Primary mRNA consists of both introns and exons.

      Correct Answer: A gene is always read in the 3’-5’ orientation and at 3’ promoter sites.

      Explanation:

      In both prokaryotes and eukaryotes RNA polymerase acts in the 5′-3′ direction and hence the RNA is transcribed in this direction. The mRNA produced is immature as it has introns as well as exons presents. It undergoes a process known as splicing to remove the exons and then interacts with the ribosomes to form proteins.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      8.5
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Genetics (16/30) 53%
Medicine (16/30) 53%
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