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  • Question 1 - 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
      23.6
      Seconds

  • Question 2 - 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
      9.1
      Seconds

  • Question 3 - 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
      12.6
      Seconds

  • Question 4 - Regarding Southern Blotting and DNA probes, which answer is FALSE ...

    Correct

    • Regarding Southern Blotting and DNA probes, which answer is FALSE

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

      Explanation:

      Restriction enzymes always cut at different positions. There are different restriction endonucleases for different nucleotide sequences.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      36.8
      Seconds

  • Question 5 - 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
      79.2
      Seconds

  • Question 6 - Which of the following statements is true regarding chromosomes? ...

    Correct

    • Which of the following statements is true regarding chromosomes?

      Your Answer: All are true

      Explanation:

      All of the above mentioned statements are true regarding chromosomes.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      11.2
      Seconds

  • Question 7 - Telomerase is active in all of the following cells, except: ...

    Incorrect

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

      Your Answer: Germ cells

      Correct 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
      18.5
      Seconds

  • Question 8 - 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
      108.4
      Seconds

  • Question 9 - In which phase do chromosomes in the nucleus become condensed into well-defined chromosomes?...

    Correct

    • In which phase do chromosomes in the nucleus become condensed into well-defined chromosomes?

      Your Answer: Metaphase

      Explanation:

      Prophase begins when the nucleus envelope disintegrates and the chromosomes start to condense. The chromosomes consist of two sister chromatids that are joined at a constriction known as centromere. When the cell reaches the metaphase the chromosomes are completely condensed and ready to align on the equatorial plate

    • This question is part of the following fields:

      • Genetics
      • Medicine
      7.4
      Seconds

  • Question 10 - 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
      11
      Seconds

  • Question 11 - Which of the following with regard to autosomal dominant disorders are true: ...

    Incorrect

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

      Your Answer: The offspring of a heterozygous individual has a 25% chance of inheriting the chromosome carrying the disease allele

      Correct 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
      15.3
      Seconds

  • Question 12 - Defects in chromosomal structure (and examples) include those mentioned below except: ...

    Incorrect

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

      Your Answer: Deletion (Wilms’ tumour, deletions of part of p11)

      Correct 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
      17.4
      Seconds

  • Question 13 - 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
      15.3
      Seconds

  • Question 14 - 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
      16.3
      Seconds

  • Question 15 - During which phase of meiosis does exchange of genetic material occur accounting for...

    Incorrect

    • During which phase of meiosis does exchange of genetic material occur accounting for genetic diversity between individuals:

      Your Answer: Interphase

      Correct Answer: Prophase 1

      Explanation:

      Prophase 1 has been divided into five different stages ( laptotene, zygotene, pachytene, diplotene ans diakinesis). In prophase 1 chromosomes are going to condense to become visible, each chromosome will contain two chromatids that are joined at the centromere. the nucleolus and nuclear envelope are going to disintegrate. the homologous chromosomes will form tetrad and crossing over will occur between the chromosomes (random exchange of genes), the point of exchange is known as the chiasmata, this increases genetic diversity.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      27.6
      Seconds

  • Question 16 - 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
      13.4
      Seconds

  • Question 17 - 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
      6.6
      Seconds

  • Question 18 - 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
      11.2
      Seconds

  • Question 19 - 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
      46.6
      Seconds

  • Question 20 - Telomerase is active in the following cells except: ...

    Incorrect

    • Telomerase is active in the following cells except:

      Your Answer: Certain liver cells

      Correct Answer: Certain osteoblasts

      Explanation:

      Some cells have the ability to reverse telomere shortening by expressing telomerase, an enzyme that extends the telomeres of chromosomes. Telomerase is an RNA-dependent DNA polymerase, meaning an enzyme that can make DNA using RNA as a template.

      Telomerase is not usually active in most somatic cells (cells of the body), but it’s active in germ cells (the cells that make sperm and eggs) and some adult stem cells. These are cell types that need to undergo many divisions, or, in the case of germ cells, give rise to a new organism with its telomeric “clock” reset.
      Interestingly, many cancer cells have shortened telomeres, and telomerase is active in these cells. If telomerase could be inhibited by drugs as part of cancer therapy, their excess division (and thus, the growth of the cancerous tumor) could potentially be stopped.
       A subset of liver cells with high levels of telomerase renews the organ during normal cell turnover and after injury.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      6.8
      Seconds

  • Question 21 - Mutation in RB can lead to the formation of which cancer? ...

    Correct

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

      Your 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
      3.8
      Seconds

  • Question 22 - 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
      17.2
      Seconds

  • Question 23 - Which of the following is true for P 53: ...

    Incorrect

    • Which of the following is true for P 53:

      Your Answer: It binds e2f and stops the cell cycle at the g2 phase

      Correct 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
      19
      Seconds

  • Question 24 - Which statement is incorrect regarding transcription of DNA? ...

    Correct

    • Which statement is incorrect regarding transcription of DNA?

      Your 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
      12.5
      Seconds

  • Question 25 - 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
      10.8
      Seconds

  • Question 26 - In Restriction Fragment Length Polymorphism (RFLP), the DNA fragments are separated by length through...

    Correct

    • In Restriction Fragment Length Polymorphism (RFLP), the DNA fragments are separated by length through a process known as:

      Your Answer: 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
      11.7
      Seconds

  • Question 27 - Which part of the chromosome plays a role in preserving its integrity and...

    Incorrect

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

      Your Answer: Centromere

      Correct 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
      16.4
      Seconds

  • Question 28 - What is the structure of nucleosomes? ...

    Correct

    • What is the structure of nucleosomes?

      Your 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
      5.5
      Seconds

  • Question 29 - 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
      23.8
      Seconds

  • Question 30 - Which of the following is false with regard to the following statement: Proto-...

    Incorrect

    • 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: Mutations in the genomic DNA

      Correct 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
      19
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Genetics (21/30) 70%
Medicine (21/30) 70%
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