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  • Question 1 - Regarding Gene Knockout Mouse Models, all are true except: ...

    Incorrect

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

      Your Answer: RFLP analysis is slow and cumbersome and is now largely obsolete

      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      • RFLP analysis is slow and cumbersome and is now largely obsolete, having been replaced by more efficient techniques.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
      15.7
      Seconds

  • Question 2 - In meiosis, the period of prophase 1 involves: ...

    Correct

    • In meiosis, the period of prophase 1 involves:

      Your 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
      21.4
      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
      73.8
      Seconds

  • Question 4 - 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
      17.2
      Seconds

  • Question 5 - 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
      34
      Seconds

  • Question 6 - 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
      33.8
      Seconds

  • Question 7 - 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
      28.7
      Seconds

  • Question 8 - In which phase do chromosomes in the nucleus become completely condensed into well-defined...

    Correct

    • In which phase do chromosomes in the nucleus become completely 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
      43
      Seconds

  • Question 9 - 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
      58
      Seconds

  • Question 10 - 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
      62.6
      Seconds

  • Question 11 - Which statement is incorrect? ...

    Correct

    • Which statement is incorrect?

      Your Answer: Translation begins when the triplet (UGA) encoding for methionine is encountered.

      Explanation:

      Translation being when the codon for methionine is encountered which is AUG not UGA. This process is known as initiation. All the other options are correct.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      276.8
      Seconds

  • Question 12 - Which of the following are true with regard to autosomal recessive disorders: ...

    Correct

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

      Your Answer: All are true

      Explanation:

      All are true for autosomal recessive disorders.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      41.2
      Seconds

  • Question 13 - Regarding Southern Blotting and DNA probes, which answer is FALSE ...

    Incorrect

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

      Your Answer: Gene probes can be labelled with radioactive isotopes g 32 p

      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
      24.1
      Seconds

  • Question 14 - 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: Anaphase 1

      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
      30.2
      Seconds

  • Question 15 - 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
      16.8
      Seconds

  • Question 16 - 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
      20.3
      Seconds

  • Question 17 - 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: With insertion or deletion of one or more bases it causes a frame shift mutation

      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
      347.5
      Seconds

  • Question 18 - 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
      36.5
      Seconds

  • Question 19 - 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
      18.8
      Seconds

  • Question 20 - In Restriction Fragment Length Polymorphism (RFLP), the DNA fragments are separated by length through...

    Incorrect

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

      Your Answer: Translocation

      Correct 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
      17.2
      Seconds

  • Question 21 - The process whereby DNA fragments are separated by size and charge is called:...

    Incorrect

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

      Your Answer: Northern blotting

      Correct 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
      106.6
      Seconds

  • Question 22 - The chromosomes that principally encode for proteins or RNA molecules involved in mitochondrial...

    Incorrect

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

      Your Answer: In the rough endoplasmic reticulum

      Correct 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
      39.9
      Seconds

  • Question 23 - Which of the following is not true regarding mitochondrial chromosome disorders? ...

    Incorrect

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

      Your Answer: Mitochondrial chromosome defects are inherited from one’s mother

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

      Explanation:

      Any point mutation in any part of the mitochondrial DNA will lead to a mutated mitochondria and will likewise have its ill effect on the body.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      10.1
      Seconds

  • Question 24 - 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:

      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
      16.8
      Seconds

  • Question 25 - 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
      16.2
      Seconds

  • Question 26 - 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
      9.9
      Seconds

  • Question 27 - The process by which DNA fragments are separated by gel and transferred onto...

    Incorrect

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

      Your Answer: Central blotting

      Correct 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
      14.8
      Seconds

  • Question 28 - Carcinogens found in cigarette smoke can transform proto-oncogenes to oncogenes through: ...

    Incorrect

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

      Your Answer: Viral stimulation

      Correct 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
      17.3
      Seconds

  • Question 29 - 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:

      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
      0
      Seconds

  • Question 30 - 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

SESSION STATS - PERFORMANCE PER SPECIALTY

Genetics (19/28) 68%
Medicine (19/28) 68%
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