Concept of Cell as Structural and Functional Unit of the Body
Q. 1. Define cell
Cell - basic structural and functional unit of living organisms. It has a defined shape, size, and structure. It performs various functions such as metabolism, reproduction, and response to stimuli.
Q. 2. Name the components of cell
Components of cell:
- Cell membrane (plasma membrane)
- Cytoplasm
- Nucleus
- Mitochondria
- Ribosomes
- Endoplasmic reticulum (ER)
- Golgi apparatus
- Lysosomes
- Cytoskeleton
- Peroxisomes
Q. 3. Mention their functions of cell organelle
Functions of cell organelles:
- Cell membrane: regulates the movement of substances in and out of the cell, maintains cell shape and structure
- Cytoplasm: contains water, salts, sugars, and various organelles, provides environment for cellular activities
- Nucleus: contains DNA, controls cell growth, division, and function
- Mitochondria: generates energy for the cell through cellular respiration
- Ribosomes: synthesizes proteins
- Endoplasmic reticulum (ER): involved in protein synthesis, transport, and modification
- Golgi apparatus: modifies, sorts, and packages proteins and lipids for secretion or use within the cell
- Lysosomes: contains digestive enzymes, breaks down and recycles cellular waste and foreign substances
- Cytoskeleton: provides structure, shape, and support to the cell, involved in cell movement and division
- Peroxisomes: involved in breakdown of fatty acids and amino acids
Q. 4. Mention the types of cell division
Types of cell division:
- Mitosis: produces two daughter cells with the same number and type of chromosomes as the parent cell
- Meiosis: produces four non-identical daughter cells with half the number of chromosomes as the parent cell
- Binary fission: a type of asexual reproduction in which a single cell divides into two identical daughter cells
- Regeneration: the process of replacing or restoring lost or damaged cells, tissues, or organs
Q. 5. Explain their significance
Significance of cell division:
- Mitosis: essential for growth, repair, and maintenance of tissues and organs
- Meiosis: necessary for reproduction and genetic variation
- Binary fission: allows single-celled organisms to reproduce and colonize new environments
- Regeneration: enables organisms to replace damaged or lost cells, tissues, or organs, maintaining overall health and function
Q. 6. Draw a simple text-based diagram to show cell division
Meiosis ↓ Formation of gametes ↓ Fertilisation ↓ Formation of zygote
Q. 7. Explain the process of mitosis
Mitosis
- Interphase → DNA replication
- Prophase → chromatin condensation, spindle formation
- Metaphase → chromosome alignment
- Anaphase → sister chromatids separate
- Telophase → nuclear envelope reforms
- Cytokinesis → cytoplasm divides
Q. 8. Explain the process of meiosis
Meiosis
- Prophase I → homologous chromosomes pair, crossing over
- Metaphase I → homologous chromosomes align
- Anaphase I → homologous chromosomes separate
- Telophase I → cytoplasm divides
- Prophase II → chromosomes condense
- Metaphase II → sister chromatids align
- Anaphase II → sister chromatids separate
- Telophase II → nuclear envelope reforms
Q. 9. Explain the significance of mitosis in growth and development
Mitosis is essential for growth, repair, and maintenance of tissues and organs. It allows for the replacement of old or damaged cells, maintaining overall health and function.
Q. 10. Explain the significance of meiosis in reproduction
Meiosis is necessary for reproduction and genetic variation. It produces non-identical gametes that combine to form unique offspring, increasing genetic diversity.
Q. 11. Explain the importance of cell division in regeneration
Regeneration enables organisms to replace damaged or lost cells, tissues, or organs, maintaining overall health and function. It is essential for the survival and success of many organisms.