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  • Question 1 - In RFLP (restriction fragment length polymorphism), the DNA fragments are separated by length...

    Incorrect

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

      Your Answer: Deletion

      Correct 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
      7.8
      Seconds

  • Question 2 - The length of DNA is generally measured in terms of number of: ...

    Incorrect

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

      Your Answer:

      Correct 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
      0
      Seconds

  • Question 3 - 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

  • Question 4 - Telomerase is active in the following cells except: ...

    Incorrect

    • Telomerase is active in the following cells except:

      Your Answer:

      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
      0
      Seconds

  • Question 5 - 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:

      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
      0
      Seconds

  • Question 6 - Which of the following with regard to DNA mutations does not fit: ...

    Incorrect

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

      Your Answer:

      Correct 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
      0
      Seconds

  • Question 7 - The length of DNA is generally measured in terms of the number of:...

    Incorrect

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

      Your Answer:

      Correct 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
      0
      Seconds

  • Question 8 - 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:

      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
      0
      Seconds

  • Question 9 - In meiosis, the period of prophase 1 involves: ...

    Incorrect

    • In meiosis, the period of prophase 1 involves:

      Your Answer:

      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
      0
      Seconds

  • Question 10 - Regarding restriction fragment length polymorphisms (RFLP) and Gene Knockout Mouse Models. All are...

    Incorrect

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

      Your Answer:

      Correct 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
      0
      Seconds

  • Question 11 - At the end of which phase will P53 halt the cell cycle? ...

    Incorrect

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

      Your Answer:

      Correct 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
      0
      Seconds

  • Question 12 - In most somatic cells telomeres progressively shorten as: ...

    Incorrect

    • In most somatic cells telomeres progressively shorten as:

      Your Answer:

      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
      0
      Seconds

  • Question 13 - What is the structure of nucleosomes? ...

    Incorrect

    • What is the structure of nucleosomes?

      Your Answer:

      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
      0
      Seconds

  • Question 14 - Restriction Enzymes... ...

    Incorrect

    • Restriction Enzymes...

      Your Answer:

      Correct 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
      0
      Seconds

  • Question 15 - During which stage does the mitotic apparatus dissolute? ...

    Incorrect

    • During which stage does the mitotic apparatus dissolute?

      Your Answer:

      Correct 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
      0
      Seconds

  • Question 16 - During which phase are the 2 chromatids pulled apart at the centromere? ...

    Incorrect

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

      Your Answer:

      Correct 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
      0
      Seconds

  • Question 17 - Which of the following is true for P53: ...

    Incorrect

    • Which of the following is true for P53:

      Your Answer:

      Correct 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
      0
      Seconds

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

    Incorrect

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

      Your Answer:

      Correct 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
      0
      Seconds

  • Question 19 - 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:

      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
      0
      Seconds

  • Question 20 - 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:

      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
      0
      Seconds

  • Question 21 - Which statement about X linked dominant disorders is FALSE? ...

    Incorrect

    • Which statement about X linked dominant disorders is FALSE?

      Your Answer:

      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
      0
      Seconds

  • Question 22 - Regarding Southern Blotting and DNA probes, which answer is FALSE ...

    Incorrect

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

      Your Answer:

      Correct 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
      0
      Seconds

  • Question 23 - When during the cell cycle do the centrioles replicate? ...

    Incorrect

    • When during the cell cycle do the centrioles replicate?

      Your Answer:

      Correct Answer: G1 phase

      Explanation:

      During G1 phase the cell will prepare for cell division. All the organelles will start to duplicate in this phase and the cell will begin to grow whilst proteins are also synthesized.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      0
      Seconds

  • Question 24 - Regarding Gene Knockout Mouse Models, all are true except: ...

    Incorrect

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

      Your Answer:

      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
      0
      Seconds

  • Question 25 - Which statement is correct? ...

    Incorrect

    • Which statement is correct?

      Your Answer:

      Correct 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
      0
      Seconds

  • Question 26 - The enzyme responsible for telomeres maintaining their length after cell division is called:...

    Incorrect

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

      Your Answer:

      Correct 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
      0
      Seconds

  • Question 27 - Normal eukaryote somatic cells have: ...

    Incorrect

    • Normal eukaryote somatic cells have:

      Your Answer:

      Correct Answer: 23 pairs of chromosomes

      Explanation:

      A normal somatic eukaryotic cell contains 46 chromosomes i.e. 23 pairs.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      0
      Seconds

  • Question 28 - When during the cell cycle does DNA replication occur? ...

    Incorrect

    • When during the cell cycle does DNA replication occur?

      Your Answer:

      Correct Answer: S phase

      Explanation:

      The S phase is known as the synthesis phase. During this phase DNA will begin to replicated, as well as the synthesis of the centrosomes and associated proteins.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      0
      Seconds

  • Question 29 - Which of the following is true for P 53: ...

    Incorrect

    • Which of the following is true for P 53:

      Your Answer:

      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
      0
      Seconds

  • Question 30 - With regard to X-linked disorders which of the following are true: ...

    Incorrect

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

      Your Answer:

      Correct 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
      0
      Seconds

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