Advertisements
Advertisements
प्रश्न
Can there be DNA replication without cell division?
उत्तर
Indeed. Endomitosis is the process by which a set of chromosomes in the nucleus multiply without undergoing cytokinesis or karyokinesis, producing several copies in every cell. There are two varieties.
- Polyteny: In this case, chromosomes split and re-divide without chromatid separation, resulting in multistranded chromosomes that contain several copies of DNA. These polytene (many stranded) chromosomes, such as the Drosophila polytene (salivary glands) chromosome, have 512–1024 chromatids and do not go through the cell cycle. The quantity of chromosomal sets remains unchanged in this instance.
- Polyploidy (endoduplication): Here, the nucleus does not divide; instead, each set of chromosomes divides together with its chromatids. As a result, there are more sets of chromosomes in the nucleus (4x, 8x, etc.). We refer to this expansion in chromosomal sets as polyploidy. Granosan and colchicine have the ability to induce it. These chromosomes travel through the cell cycle and are normal.
APPEARS IN
संबंधित प्रश्न
Discuss with your teacher about haploid insects and lower plants where cell-division occurs.
Discuss with your teacher about some haploid cells in higher plants where cell-division does not occur.
Choose the ODD one out from the following terms given and name the CATEGORY to which the others belong:
Lumen, muscular tissue, connective tissue, pericardium
Spindle apparatus is formed during which stage of mitosis?
Choose the correct option.
How many chromatides are present in anaphase-I of meiosis-I of a diploid cell having 20 chromosomes?
Choose the correct option.
Find incorrect statement.
Choose the correct option.
Histone proteins are synthesized during ______.
Answer the following question.
Students were shown some slides of cancerous cells. Teacher made a comment as if there would have been control at one of its cell cycle phase, there wouldn’t have been a condition like this. Which phase the teacher was referring to?
Answer the following question.
Some Mendelian crossing experimental results were shown to the students. Teacher informed that there are two genes located on the same chromosome. He enquired if they will be ever separated from each other?
Anaphase promoting complex APC is a protein degradation machinery necessary for proper mitosis of animal cells. If APC is defective in human cell, which of the following is expected to occur?
In meiosis crossing over is initiated at ______.
The paring of homologous chromosomes on meiosis is known as ______.
Differentiate cytokinesis in plant cells and animal cells.
Write about Pachytene of Prophase I.
Write about Diplotene of Prophase I.
If a tissue has at a given time 1024 cells, how many cycles of mitosis had the original parental single cell undergone?
An anther has 1200 pollen grains. How many pollen mother cells must have been there to produce them?
Name the pathological condition when uncontrolled cell division occurs.
