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Chapter Analysis
Intermediate11 pages • EnglishQuick Summary
The chapter on 'Cell Cycle and Cell Division' provides an in-depth look at the processes cells undergo to duplicate and divide. It covers the phases of the cell cycle, including interphase and mitosis, and explains the importance of each phase in cell growth and reproduction. The chapter also discusses meiosis, highlighting its role in reducing chromosome numbers by half and increasing genetic diversity. Additionally, the text delves into the significance of these cell division processes in the life cycles of organisms.
Key Topics
- •Cell cycle phases
- •Mitosis process and stages
- •Significance of mitosis
- •Meiosis process and stages
- •Significance of meiosis
- •Genetic variation through meiosis
- •Cytokinesis in plants vs animals
- •Equational and reductional division
Learning Objectives
- ✓Understand the phases of the cell cycle and their significance
- ✓Explain the process and stages involved in mitosis
- ✓Distinguish between mitosis and meiosis
- ✓Describe the process and significance of meiosis
- ✓Identify different types of cell divisions and their roles
- ✓Recognize the importance of genetic variability through meiosis
Questions in Chapter
What is the average cell cycle span for a mammalian cell?
Page 130
Distinguish cytokinesis from karyokinesis.
Page 130
Describe the events taking place during interphase.
Page 130
What is Go (quiescent phase) of cell cycle?
Page 130
Why is mitosis called equational division?
Page 130
Name the stage of cell cycle at which one of the following events occur: (i) Chromosomes are moved to spindle equator. (ii) Centromere splits and chromatids separate. (iii) Pairing between homologous chromosomes takes place. (iv) Crossing over between homologous chromosomes takes place.
Page 130
Describe the following: (a) synapsis (b) bivalent (c) chiasmata
Page 130
How does cytokinesis in plant cells differ from that in animal cells?
Page 130
Find examples where the four daughter cells from meiosis are equal in size and where they are found unequal in size.
Page 130
Distinguish anaphase of mitosis from anaphase I of meiosis.
Page 130
List the main differences between mitosis and meiosis.
Page 130
What is the significance of meiosis?
Page 130
Discuss with your teacher about (i) haploid insects and lower plants where cell-division occurs, and (ii) some haploid cells in higher plants where cell-division does not occur.
Page 130
Can there be mitosis without DNA replication in ‘S’ phase?
Page 130
Can there be DNA replication without cell division?
Page 130
Analyse the events during every stage of cell cycle and notice how the following two parameters change (i) number of chromosomes (N) per cell (ii) amount of DNA content (C) per cell
Page 130
Additional Practice Questions
Explain the importance of the G1 phase in the cell cycle.
mediumAnswer: The G1 phase is crucial as it marks the interval between mitosis and the initiation of DNA replication. During this phase, the cell grows, carries out normal metabolism, and duplicates organelles.
How do plant cells perform cytokinesis differently than animal cells?
mediumAnswer: In plant cells, cytokinesis involves the formation of a cell plate that grows outward to meet existing cell walls, eventually leading to cell division. In contrast, animal cells use a cleavage furrow that constricts the cell membrane until the cell splits into two.
What role does the spindle apparatus play during mitosis?
mediumAnswer: The spindle apparatus is essential for aligning chromosomes at the cell's equatorial plane and for separating sister chromatids into daughter cells during mitosis.
Describe the prophase stage in mitosis.
easyAnswer: During prophase, chromosomal material condenses to form compact mitotic chromosomes, centrosomes move to opposite poles, and the spindle apparatus forms.
Why is meiosis referred to as a reductional division?
mediumAnswer: Meiosis is known as a reductional division because it reduces the chromosome number by half, ensuring the formation of haploid gametes, which is essential for maintaining chromosome number stability across generations.
NCERT Exemplar
AvailablePractice with NCERT Exemplar problems and solutions for this chapter. Exemplar problems are designed to help you master the concepts with advanced-level questions.
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