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  • Question 1 - 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
      8
      Seconds

  • Question 2 - During which phase of the cell cycle does transcription of DNA synthesis molecules...

    Correct

    • During which phase of the cell cycle does transcription of DNA synthesis molecules 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.

      Interphase is composed of G1 phase (cell growth), followed by S phase (DNA synthesis), followed by G2 phase (cell growth). At the end of interphase comes the mitotic phase, which is made up of mitosis and cytokinesis and leads to the formation of two daughter cells.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      11.2
      Seconds

  • Question 3 - 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
      9.6
      Seconds

  • Question 4 - 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
      10.5
      Seconds

  • Question 5 - Which statement about X linked dominant disorders is FALSE? ...

    Incorrect

    • Which statement about X linked dominant disorders is FALSE?

      Your Answer: These are rare disorders.

      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
      28.7
      Seconds

  • Question 6 - 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
      12
      Seconds

  • Question 7 - During which stage does the mitotic apparatus dissolute? ...

    Correct

    • During which stage does the mitotic apparatus dissolute?

      Your Answer: Telophase

      Explanation:

      In telophase the nuclear envelope along with the nucleolus will reappear. The daughter nuclei will enlarge as the chromosome will decondense again. Along with this, cytokinesis will occur. At the end of cytokinesis the daughter centrioles will move from the poles to the intercellular bridge where they will be disassembled and complete the separation of the daughter cells

    • This question is part of the following fields:

      • Genetics
      • Medicine
      9
      Seconds

  • Question 8 - 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
      14.3
      Seconds

  • Question 9 - 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
      7.7
      Seconds

  • Question 10 - Normal parents have a child with a recessive condition, Tay Sachs. The chance...

    Incorrect

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

      Your Answer: 0%

      Correct 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
      64.4
      Seconds

  • Question 11 - In most somatic cells telomeres progressively shorten as: ...

    Correct

    • In most somatic cells telomeres progressively shorten as:

      Your 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
      10.3
      Seconds

  • Question 12 - 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
      9.4
      Seconds

  • Question 13 - When one of the two copies of the autosomes has a mutation and...

    Correct

    • 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 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
      25.4
      Seconds

  • Question 14 - 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
      14
      Seconds

  • Question 15 - In meiosis, the period of prophase 1 involves: ...

    Incorrect

    • In meiosis, the period of prophase 1 involves:

      Your Answer: The production of two identical daughter cells

      Correct Answer: Replicated DNA condensing to form visible chromosomes

      Explanation:

      Prophase 1 has been divided into five different stages (laptotene, zygotene, pachytene, diplotene and diakinesis). In prophase 1, chromosomes are going to condense to become visible, each chromosome will contain two chromatids that are joined at the centromere.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      9.4
      Seconds

  • Question 16 - The following cells replicate without shortening their telomeres because they express telomerase. ...

    Incorrect

    • The following cells replicate without shortening their telomeres because they express telomerase.

      Your Answer: Red blood cells

      Correct Answer: Germ cells

      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. During replication telomeres may be lost resulting in cell death.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      12.5
      Seconds

  • Question 17 - Which of the following conditions is NOT X-linked recessive? ...

    Incorrect

    • Which of the following conditions is NOT X-linked recessive?

      Your Answer: Haemophilia B

      Correct Answer: Cystic fibrosis

      Explanation:

      Cystic fibrosis is a autosomal recessive disease with an incidence of about 1 in 2500 live births. The most common mutation occurs in the long arm of chromosome 7 which codes for the chloride channel (cystic fibrosis transmembrane conductance regulator) gene.

      To have CF, a child must inherit two abnormal genes—one from each parent. The recessive CF gene can occur in both boys and girls because it is located on non-sex-linked chromosomes called autosomal chromosomes.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      6.8
      Seconds

  • Question 18 - The telomerase is capable of adding several more repeats of telomeres at which...

    Incorrect

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

      Your Answer: 2nd end

      Correct 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
      4.3
      Seconds

  • Question 19 - “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
      5.7
      Seconds

  • Question 20 - In which phase do chromosomes in the nucleus become completely condensed into well-defined...

    Incorrect

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

      Your Answer:

      Correct 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
      0
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Genetics (16/19) 84%
Medicine (16/19) 84%
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