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  • Question 1 - Which of the following statements is true regarding chromosomes? ...

    Incorrect

    • Which of the following statements is true regarding chromosomes?

      Your Answer: Diploid human cells have 46 chromosomes, 23 inherited from each parent

      Correct 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
      14.1
      Seconds

  • Question 2 - During which phase of meiosis does exchange of genetic material occur accounting for...

    Correct

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

      Your 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
      3.3
      Seconds

  • Question 3 - 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
      5.4
      Seconds

  • Question 4 - 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 5 - Critical shortening of Telomeres result in: ...

    Incorrect

    • Critical shortening of Telomeres result in:

      Your Answer:

      Correct 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
      0
      Seconds

  • Question 6 - 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 7 - Which statement is incorrect regarding transcription of DNA? ...

    Incorrect

    • Which statement is incorrect regarding transcription of DNA?

      Your Answer:

      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
      0
      Seconds

  • Question 8 - 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 9 - Three adjacent nucleotides code for a particular amino acid. These are called codons....

    Incorrect

    • 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:

      Correct 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
      0
      Seconds

  • Question 10 - Southern Blotting and DNA probes: ...

    Incorrect

    • Southern Blotting and DNA probes:

      Your Answer:

      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
      0
      Seconds

  • Question 11 - 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 12 - The process where by DNA fragments are separated by size and charge is...

    Incorrect

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

      Your Answer:

      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
      0
      Seconds

  • Question 13 - 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:

      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
      0
      Seconds

  • Question 14 - 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:

      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
      0
      Seconds

  • Question 15 - 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:

      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
      0
      Seconds

  • Question 16 - 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:

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

      Explanation:

      Mitochondrial DNA (mtDNA) does indeed lack introns, meaning that its genes are closely packed with coding sequences. This actually means that any point mutation in the mtDNA is more likely to have an effect, not less. The lack of introns means there are fewer non-coding regions where mutations can occur without affecting gene function. Thus, mutations in mtDNA often have significant consequences because they are more likely to alter essential coding sequences.

      The other statements are true:

      • Most mitochondrial diseases are myopathies and neuropathies with a maternal pattern of inheritance: This is correct because mtDNA is inherited maternally, and many mitochondrial disorders affect muscle and nerve function.
      • Retinal degeneration, diabetes mellitus, and some forms of hearing loss are some of the other diseases attributed to mitochondrial chromosome defects: These are indeed conditions associated with mitochondrial defects.
      • Mitochondrial chromosome defects are inherited from one’s mother: This is correct, as mtDNA is passed from mother to offspring.
      • Leber’s hereditary optic neuropathy (LHON), the commonest cause of blindness in young men, is an example of a mitochondrial chromosome defect: This is true; LHON is a well-known mitochondrial disorder.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      0
      Seconds

  • Question 17 - 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:

      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
      0
      Seconds

  • Question 18 - 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 19 - 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:

      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
      0
      Seconds

  • Question 20 - 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:

      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
      0
      Seconds

  • Question 21 - 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 22 - Telomeres are best described as: ...

    Incorrect

    • Telomeres are best described as:

      Your Answer:

      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
      0
      Seconds

  • Question 23 - 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:

      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
      0
      Seconds

  • Question 24 - 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 25 - During which phase of the cell cycle does transcription of DNA synthesis molecules...

    Incorrect

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

      Your Answer:

      Correct 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
      0
      Seconds

  • Question 26 - 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:

      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
      0
      Seconds

  • Question 27 - 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 28 - Which statement is correct regarding mRNA? ...

    Incorrect

    • Which statement is correct regarding mRNA?

      Your Answer:

      Correct Answer: mRNAs are mainly found in the nucleus and cytoplasm of a cell.

      Explanation:

      mRNA is transcribed from DNA and is carried to the cytosol to be translated. Hence it is mainly found in the cytosol and the nucleus of a cell. It is single stranded and contains the base uracil instead of thymine.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      0
      Seconds

  • Question 29 - “Ploidy” is a term used to refer to the number of chromosomes in...

    Incorrect

    • “Ploidy” is a term used to refer to the number of chromosomes in cells. Cancer cells are commonly:

      Your Answer:

      Correct 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
      0
      Seconds

  • Question 30 - Immortality can result from over expression of which enzyme? ...

    Incorrect

    • Immortality can result from over expression of which enzyme?

      Your Answer:

      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
      0
      Seconds

  • Question 31 - With regards to P53, which statement is NOT true? ...

    Incorrect

    • With regards to P53, which statement is NOT true?

      Your Answer:

      Correct Answer: P53 is a RNA binding protein

      Explanation:

      P53 is a tumour suppressor gene. It is not an RNA binding protein. It has been implicated in almost all tumours. It regulates the progression from G1 to the S phase of the cell cycle and is activated in response to damaged DNA.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      0
      Seconds

  • Question 32 - In which stage of mitosis are the chromosomes most obvious or prominent? ...

    Incorrect

    • In which stage of mitosis are the chromosomes most obvious or prominent?

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

    Incorrect

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

      Your Answer:

      Correct 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
      0
      Seconds

  • Question 34 - Telomerase is active in all of the following cells, except: ...

    Incorrect

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

      Your Answer:

      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
      0
      Seconds

  • Question 35 - 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 36 - Near the transcription site of a gene, the site at which RNA polymerase...

    Incorrect

    • Near the transcription site of a gene, the site at which RNA polymerase and its cofactors bind is known as the:

      Your Answer:

      Correct 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
      0
      Seconds

  • Question 37 - 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:

      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
      0
      Seconds

  • Question 38 - 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 39 - 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:

      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
      0
      Seconds

  • Question 40 - 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 41 - Male to male transmission is a key factor of which type of inheritance?...

    Incorrect

    • Male to male transmission is a key factor of which type of inheritance?

      Your Answer:

      Correct 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
      0
      Seconds

  • Question 42 - 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:

      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
      0
      Seconds

  • Question 43 - 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:

      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
      0
      Seconds

  • Question 44 - 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 45 - 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 46 - 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 47 - The process of DNA amplification and quantification is called: ...

    Incorrect

    • The process of DNA amplification and quantification is called:

      Your Answer:

      Correct 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
      0
      Seconds

  • Question 48 - What is the protective hexametric sequence at the ends of chromosomes called? ...

    Incorrect

    • What is the protective hexametric sequence at the ends of chromosomes called?

      Your Answer:

      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
      0
      Seconds

  • Question 49 - Regarding Polymerase Chain Reaction, all are true except: ...

    Incorrect

    • Regarding Polymerase Chain Reaction, all are true except:

      Your Answer:

      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
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  • Question 50 - 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:

      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
      0
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  • Question 51 - 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:

      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
      0
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  • Question 52 - Which of the following are true with regard to autosomal recessive disorders: ...

    Incorrect

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

      Your Answer:

      Correct Answer: All are true

      Explanation:

      All are true for autosomal recessive disorders.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      0
      Seconds

  • Question 53 - During which phase of the cell cycle does DNA synthesis occur? ...

    Incorrect

    • During which phase of the cell cycle does DNA synthesis occur?

      Your Answer:

      Correct 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
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  • Question 54 - 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:

      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
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  • Question 55 - 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
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  • Question 56 - 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
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  • Question 57 - Under normal conditions (where n represents the number of chromosome pairs), just before...

    Incorrect

    • 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:

      Correct 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
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  • Question 58 - 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:

      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
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  • Question 59 - Which of the following statements is true about chromosomes? ...

    Incorrect

    • Which of the following statements is true about chromosomes?

      Your Answer:

      Correct 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
      0
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  • Question 60 - Which of the following statements is not true about mitochondrial chromosomes? ...

    Incorrect

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

      Your Answer:

      Correct 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
      0
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  • Question 61 - In DNA cloning and sequencing, the bases in nucleotides chains are bound together...

    Incorrect

    • In DNA cloning and sequencing, the bases in nucleotides chains are bound together by:

      Your Answer:

      Correct 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
      0
      Seconds

  • Question 62 - 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 63 - 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 64 - 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
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  • Question 65 - When 2 nucleotide chains of DNA bind together, thymine is bound to: ...

    Incorrect

    • When 2 nucleotide chains of DNA bind together, thymine is bound to:

      Your Answer:

      Correct 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
      0
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  • Question 66 - In which phase do chromosomes in the nucleus become condensed into well-defined chromosomes?...

    Incorrect

    • In which phase do chromosomes in the nucleus become 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
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  • Question 67 - 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 68 - Consanguinity shows a strong association with which pattern of inheritance? ...

    Incorrect

    • Consanguinity shows a strong association with which pattern of inheritance?

      Your Answer:

      Correct Answer: Autosomal recessive

      Explanation:

      Consanguinity involves being from the same kinship as another person. It is a common feature of an autosomal recessive mode of inheritance

    • This question is part of the following fields:

      • Genetics
      • Medicine
      0
      Seconds

  • Question 69 - 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 70 - 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 71 - What is the role of cyclin and cyklin-dependent kinases in mitosis: ...

    Incorrect

    • What is the role of cyclin and cyklin-dependent kinases in mitosis:

      Your Answer:

      Correct Answer: Phosphorylation of proteins that make up pre-replication complexes

      Explanation:

      There are certain regulators of the cell cycles that mediate progression through the cell cycle. These are cyclins and cyklin-dependent kinases (CDKs). They form a complex that phosphorylates protein involved in the cell cycle.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      0
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  • Question 72 - 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

  • Question 73 - Regarding DNA cloning and sequencing, all of the following are true, except: ...

    Incorrect

    • Regarding DNA cloning and sequencing, all of the following are true, except:

      Your Answer:

      Correct 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
      0
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  • Question 74 - 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 75 - 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
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      Seconds

  • Question 76 - 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 77 - 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:

      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
      0
      Seconds

  • Question 78 - 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 79 - Which statement is incorrect? ...

    Incorrect

    • Which statement is incorrect?

      Your Answer:

      Correct 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
      0
      Seconds

  • Question 80 - The mitochondrial chromosome is a circular DNA molecule. They encode for proteins needed...

    Incorrect

    • The mitochondrial chromosome is a circular DNA molecule. They encode for proteins needed for ATP production. These proteins are also essential for:

      Your Answer:

      Correct Answer: Apoptotic cell death

      Explanation:

      The intrinsic pathway or the mitochondrial pathway of apoptosis is activated due to the loss of BCL-2 and other antiapoptotic proteins. This loss results in the increased membrane permeability and release of cytochrome C which activates caspases downstream resulting in apoptosis.

    • This question is part of the following fields:

      • Genetics
      • Medicine
      0
      Seconds

  • Question 81 - 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:

      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
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      Seconds

  • Question 82 - Which of the following conditions is NOT X-linked recessive? ...

    Incorrect

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

      Your Answer:

      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
      0
      Seconds

  • Question 83 - 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

SESSION STATS - PERFORMANCE PER SPECIALTY

Genetics (2/3) 67%
Medicine (2/3) 67%
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