Class 11 Biology - ISC
Cell Cycle and Cell Division
The chapter 'Cell Cycle and Cell Division' explores how single cells grow, replicate their genetic material, and divide to form new cells, which is fundamental for growth, tissue repair, and reproduction in all living organisms. For ISC Class 11 Biology students, this chapter is crucial as it forms the baseline for genetics, molecular biology, and biotechnology. Board exams frequently test conceptual understanding of mitotic and meiotic phases, checkpoints of the cell cycle, and the significance of crossing over. Scoring well here requires mastering the sequence of events in interphase, karyokinesis, and cytokinesis in both plants and animals.
Start Learning FreeKey Concepts
Cell Cycle
The ordered series of events involving cell growth and division, comprising a long non-dividing Interphase (G1, S, G2 phases) and a short M-phase.
Mitosis
Equational division occurring in somatic cells where a parent cell divides to produce two genetically identical daughter cells with the same chromosome number.
Meiosis
Reductional division occurring in germ cells, reducing the chromosome number by half and producing four genetically distinct haploid cells through two successive divisions.
Crossing Over
The exchange of genetic material between non-sister chromatids of homologous chromosomes during pachytene of meiotic prophase I, leading to genetic variation.
G0 Phase (Quiescent Stage)
A state where cells exit the active cell cycle to remain metabolically active without proliferating, unless called upon to divide by environmental cues.
Important Formulas
Board Exam Info
In the ISC Class 11 Biology theory paper, this chapter typically carries around 6 to 8 marks. Questions often include diagram-based identification of mitotic/meiotic phases, differences between plant and animal cytokinesis, significance of meiosis, and numerical problems related to DNA content and chromosome number during various phases of the cell cycle.
Frequently Asked Questions
What is the main difference between plant and animal cytokinesis?
In plant cells, cytokinesis occurs through cell plate formation starting centrifugally from the center, whereas in animal cells, it occurs through cleavage furrow formation proceeding centripetally.
Why is meiosis called reductional division?
Meiosis is called reductional division because the chromosome number is halved from diploid (2n) to haploid (n) in the first meiotic division.
What happens if the cell cycle is not regulated?
Loss of cell cycle regulation can lead to uncontrolled and continuous cell division, resulting in the formation of masses of cells called tumors or cancer.
Learn Cell Cycle and Cell Division with Your AI Tutor
10 different ways to study this chapter. Free for 3 chapters per day.
Lecture
Key Points
Interactive
Quiz
Flashcards