Spindle fibers attach to kinetochores of chromosomes during
prophase
metaphase
anaphase
telophase
Doubling of the number of chromosomes can be achieved by disrupting mitotic cell division soon after
anaphase
telophase
prophase
metaphase
Doubling of the number of chromosomes within a cell can be achieved by disrupting mitotic cell division soon after metaphase stage. After metaphase, each chromosome arranged at the metaphase plate splits and the two daughter chromatids begin their migration towards the two opposite poles to form two daughter cells. If this is prevented, chromosome number will get doubled.
Which one of the following never occurs during mitotic cell division?
Spindle fibers attach to kinetochores of chromosomes
Movement of centrioles towards opposite poles
Pairing of homologous chromosomes
Coiling and condensation of the chromatids
Pairing of homologous chromosomes is characteristic of meiotic cell division.
Select the incorrect statement with reference to mitosis.
All the chromosomes lie at the equator at metaphase.
Spindle fibers attach to centromere of chromosomes.
Chromosomes decondense at telophase.
Splitting of centromere occurs at anaphase.
Enter Answer here
Which of the following options gives the correct sequence of events during mitosis?
Condensation → Nuclear membrane disassembly → Arrangement at equator → Centromere division → Segregation → Telophase
Condensation → Crossing over → Nuclear membrane disassembly → Segregation → Telophase
Condensation → Arrangement at equator → Centromere division → Segregation → Telophase
Condensation → Nuclear membrane disassembly → Crossing over → Segregation → Telophase
Mitosis is divided into four phases: prophase, metaphase, anaphase, and telophase. During prophase, the indistinct and intertwined DNA molecules condense to form elongated chromosomes. The nuclear membrane disintegrates during prometaphase. During metaphase, the chromosomes align themselves at the equatorial plate. During anaphase, the centromere of each chromosome divides into two so that each chromosome comes to have its own centromere. Chromatids move towards opposite poles along the path of their chromosome fibres. Finally, during telophase, two chromosome groups reorganise to form two nuclei. Nuclear envelope reappears, Golgi complex and endoplasmic reticulum are reformed. Option (c) also gives the correct sequence of events but it misses step II (nuclear membrane disassembly). Hence, it is ruled out as the best appropriate answer is option (a)
Anaphase Promoting Complex (APC) is a protein degradation machinery necessary for proper mitosis of animal cells. If APC is defective in a human cell, which of the following is expected to occur?
Chromosomes will be fragmented.
Chromosomes will not segregate.
Recombination of chromosome arms will occur.
Chromosomes will not condense.
During anaphase in mitosis, sister chromatids segregate at opposite poles. Therefore, a defective APC will affect chromosome segregation.
Spindle fibers attach on to
centromere of the chromosome
kinetosome of the chromosome
telomere of the chromosome
kinetochore of the chromosome
Small disc-shaped structures at the surface of the centromeres are called kinetochores. These structures serve as the sites of attachment of spindle fibres to the chromosomes that are moved into position at the centre of the cell."
Which of the following is not a characteristic feature during mitosis in somatic cells?
Chromosome movement
Synapsis
Spindle fibers
Disappearance of nucleolus
Synapsis is the process of association of homologous chromosomes. It takes place during zygotene stage of prophase I of meiosis. This stage is not seen during mitosis.
