A cell at the telophase stage is observed by a student in a plant brought from a field. He tells his teacher that this cell is not like other cells at the telophase stage. There is no formation of a cell plate and the cell contains more chromosomes as compared to other dividing cells. This would result in
A cell at the telophase stage is observed by a student in a plant brought from a field. He tells his teacher that this cell is not like other cells at the telophase stage. There is no formation of a cell plate and the cell contains more chromosomes as compared to other dividing cells. This would result in
The correct option is C Polyploidy
The correct option is C.
Explanation of the correct option:
- Telophase is the fifth and final stage of mitosis when the duplicated genetic material held in the nucleus of a parent cell is separated into two identical daughter cells.
- Telophase begins when the replicated, paired chromosomes are split and dragged to opposing sides of the cell, or poles.
- A cell prepares for cell division by replicating its chromosomes, segregating them, and creating two identical nuclei during the mitotic phase.
- The cell's contents are often evenly divided into two daughter cells with identical genomes after mitosis.
- Polyploidy is a heritable phenomenon characterized by the presence of more than two full sets of chromosomes.
- Polyploids are common in plants, as well as certain types of fish and amphibians.
- Polyploids include several salamanders, frogs, and leeches.
- Failure of cytokinesis during the telophase stage of cell division results in an increase in an organism's entire set of chromosomes, which is known as polyploidy.
Explanations of the incorrect options:
Option A:
- Polyteny is defined as relating to, being, or possessing chromosomes that are made up of numerous strands with the associated chromomeres in contact.
- Polytene chromosomes are a highly amplified form of interphase chromosomes seen in Drosophila and Chironomus salivary gland cells, among other places.
- They form as a result of several rounds of DNA replication with no subsequent separation of daughter chromatids.
- Chromatin runs the entire length of a chromosome.
Option B:
- Aneuploidy is a condition when there are either too many or too few chromosomes in the daughter cells produced during mitosis.
- With the remarkable exception of trisomy 21 in humans, nearly all aneuploidies that result from errors in meiosis or during early embryonic development are fatal.
- Nondisjunction, or the failure of chromosomes to disjoin normally during meiosis, is the most frequent cause of aneuploidy.
- Although maternal meiosis I is the most frequent nondisjunction in aneuploidies, nondisjunction can also happen during meiosis I or II or during mitosis.
Option D:
- Somatic tissue culture in vitro produces progeny plants that exhibit genetic variation known as somaclonal variation.
- Theoretically, all plants that regenerate from somatic cells should produce clones of themselves.
- Somaclonal variation is the type of variation found in plants grown from plant tissue.
- Rearrangements of the chromosomes are a significant cause of this variance.
- Although not exclusively present, somaclonal variation is more prevalent in plants that have grown from calluses.
Final answer: A cell at the telophase stage is observed by a student in a plant brought from a field. He tells his teacher that this cell is not like other cells at the telophase stage. There is no formation of a cell plate and the cell contains more chromosomes as compared to other dividing cells. This would result in polyploidy.
Polyploidy
The correct option is C.
Explanation of the correct option:
- Telophase is the fifth and final stage of mitosis when the duplicated genetic material held in the nucleus of a parent cell is separated into two identical daughter cells.
- Telophase begins when the replicated, paired chromosomes are split and dragged to opposing sides of the cell, or poles.
- A cell prepares for cell division by replicating its chromosomes, segregating them, and creating two identical nuclei during the mitotic phase.
- The cell's contents are often evenly divided into two daughter cells with identical genomes after mitosis.
- Polyploidy is a heritable phenomenon characterized by the presence of more than two full sets of chromosomes.
- Polyploids are common in plants, as well as certain types of fish and amphibians.
- Polyploids include several salamanders, frogs, and leeches.
- Failure of cytokinesis during the telophase stage of cell division results in an increase in an organism's entire set of chromosomes, which is known as polyploidy.
Explanations of the incorrect options:
Option A:
- Polyteny is defined as relating to, being, or possessing chromosomes that are made up of numerous strands with the associated chromomeres in contact.
- Polytene chromosomes are a highly amplified form of interphase chromosomes seen in Drosophila and Chironomus salivary gland cells, among other places.
- They form as a result of several rounds of DNA replication with no subsequent separation of daughter chromatids.
- Chromatin runs the entire length of a chromosome.
Option B:
- Aneuploidy is a condition when there are either too many or too few chromosomes in the daughter cells produced during mitosis.
- With the remarkable exception of trisomy 21 in humans, nearly all aneuploidies that result from errors in meiosis or during early embryonic development are fatal.
- Nondisjunction, or the failure of chromosomes to disjoin normally during meiosis, is the most frequent cause of aneuploidy.
- Although maternal meiosis I is the most frequent nondisjunction in aneuploidies, nondisjunction can also happen during meiosis I or II or during mitosis.
Option D:
- Somatic tissue culture in vitro produces progeny plants that exhibit genetic variation known as somaclonal variation.
- Theoretically, all plants that regenerate from somatic cells should produce clones of themselves.
- Somaclonal variation is the type of variation found in plants grown from plant tissue.
- Rearrangements of the chromosomes are a significant cause of this variance.
- Although not exclusively present, somaclonal variation is more prevalent in plants that have grown from calluses.
Final answer: A cell at the telophase stage is observed by a student in a plant brought from a field. He tells his teacher that this cell is not like other cells at the telophase stage. There is no formation of a cell plate and the cell contains more chromosomes as compared to other dividing cells. This would result in polyploidy.
