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10/25/2018----Biology Class 11 NCERT Solutions: Chapter 15 Plant Growth and Development Part 1- Translation in Hindi, Kannada, Malayalam,, Marathi, Punjabi, Sindhi, Sindhi, Tamil, Telgu - FlexiPrep----Downloaded from flexiprep.com, Visit examrace.com for free study material, doorsteptutor.com for questions with detailed explanations, and "Examrace" YouTube channel for free, videos lectures, , Flexiprep, ▶, , Examrace 339K, , Biology Class 11 NCERT Solutions: Chapter 15 Plant Growth and, Development Part 1, Q: 1. Define growth, differentiation, development, dedifferentiation, redifferentiation,, determinate growth, meristem and growth rate., Answer, (A) Growth, It is an irreversible and permanent process, accomplished by an increase in the size of an organ, or organ parts or even of an individual cell., (B) Differentiation, It is a process in which the cells derived from the apical meristem (root and shoot apex) and the, cambium undergo structural changes in the cell wall and the protoplasm, becoming mature to, perform specific functions., (C) Development, It refers to the various changes occurring in an organism during its life cycle – from the, germination of seeds to senescence., (D) De-differentiation, It is the process in which permanent plant cells regain the power to divide under certain, conditions., (E) Re-differentiation, It is the process in which de-differentiated cells become mature again and lose their capacity to, divide., (f) Determinate growth, It refers to limited growth. For example, animals and plant leaves stop growing after having, reached maturity., (g) Meristem, In plants, growth is restricted to specialised regions where active cell divisions take place. Such a, region is called meristem. There are three types of meristems - apical meristem, lateral, meristem, and intercalary meristem., (h) Growth rate, 1 of 4
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10/25/2018----Biology Class 11 NCERT Solutions: Chapter 15 Plant Growth and Development Part 1- Translation in Hindi, Kannada, Malayalam,, Marathi, Punjabi, Sindhi, Sindhi, Tamil, Telgu - FlexiPrep----Downloaded from flexiprep.com, Visit examrace.com for free study material, doorsteptutor.com for questions with detailed explanations, and "Examrace" YouTube channel for free, videos lectures, , It can be defined as the increased growth in plants per unit time., Q: 2. Why is not any one parameter good enough to demonstrate growth throughout the life of a, flowering plant?, Answer, In plants, growth is said to have taken place when the amount of protoplasm increases., Measuring the growth of protoplasm involves many parameters such as the weight of the fresh, tissue sample, the weight of the dry tissue sample, the differences in length, area, volume, and, cell number measured during the growth period. Measuring the growth of plants using only one, parameter does not provide enough information and hence, is insufficient for demonstrating, growth., , Image of Flowering Plants Life Cycle, , 2 of 4
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10/25/2018----Biology Class 11 NCERT Solutions: Chapter 15 Plant Growth and Development Part 1- Translation in Hindi, Kannada, Malayalam,, Marathi, Punjabi, Sindhi, Sindhi, Tamil, Telgu - FlexiPrep----Downloaded from flexiprep.com, Visit examrace.com for free study material, doorsteptutor.com for questions with detailed explanations, and "Examrace" YouTube channel for free, videos lectures, , Q: 3. Describe briefly:, (A) Arithmetic growth, (B) Geometric growth, (C) Sigmoid growth curve, (D) Absolute and relative growth rates, Answer, (A) Arithmetic growth, In arithmetic growth, one of the daughter cells continues to divide, while the other differentiates, into maturity. The elongation of roots at a constant rate is an example of arithmetic growth., (B) Geometric growth, Geometric growth is characterised by a slow growth in the initial stages and a rapid growth, during the later stages. The daughter cells derived from mitosis retain the ability to divide, but, slow down because of a limited nutrient supply., , Image Shows the Types of Growth Rate, , 3 of 4
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10/25/2018----Biology Class 11 NCERT Solutions: Chapter 15 Plant Growth and Development Part 1- Translation in Hindi, Kannada, Malayalam,, Marathi, Punjabi, Sindhi, Sindhi, Tamil, Telgu - FlexiPrep----Downloaded from flexiprep.com, Visit examrace.com for free study material, doorsteptutor.com for questions with detailed explanations, and "Examrace" YouTube channel for free, videos lectures, , (C) The growth of living organisms in their natural environment is characterised by an S shaped, curve called sigmoid growth curve. This curve is divided into three phases -lag phase, log phase, or exponential phase of rapid growth, and stationary phase., Exponential growth can be expressed as:, , Q 3 Image of Exponential Phase, , Where,, , (D) Absolute and relative growth rates, Absolute growth rate refers to the measurement and comparison of total growth per unit time., Relative growth rate refers to the growth of a particular system per unit time, expressed on a, common basis., , 4 of 4
