Growth and Development in Plants – 2:
1. Which of the following is not the characteristics of the cells of the phase of elongation?
A. Increased vacuolation
B. Cell enlargement
C. Plasmodesmatal connections
D. Cell wall deposition
Answer: C
Explanation: Plasmodesmatal connections are not the characteristic cells of the phase of elongation, rather they represent the cells of the meristematic phase of growth. Some characteristics of the cells of the phase of elongation include increased vacuolation, cell enlargement and new cell wall deposition which gives strength to the existing cell wall.
2. Which zone lies next to the phase of elongation?
A. Phase of maturation
B. Meristematic zone
C. Zone of enlargement
D. Root cap
Answer: A
Explanation: Phase of maturation lies next to the phase of elongation. This phase lies away from the root apex and is formed last in the growth of the root of the plant.
3. Which of the following is a characteristic of the cells of the maturation zone?
A. Thin-walled
B. Thick-walled
C. Enlarged cells
D. Plasmodesmatal connections
Answer: B
Explanation: The cells of the maturation zone, attain their maximal size in terms of wall thickening and protoplasmic modifications. From this region, some of the epidermal cells form very fine and delicate, thread-like structures called root hair.
4. What is the growth rate?
A. Increased growth per unit distance
B. Decreased growth per unit distance
C. Increased growth per unit time
D. Intermediate growth between time and distance
Answer: C
Explanation: The increased growth per unit time is termed as growth rate. Thus, the rate of growth can be expressed mathematically and can be represented with the help of various charts and graphs.
5. The growth rate is generally of how many types?
A. One
B. Two
C. Four
D. Five
Answer: B
Explanation: An organism or a part of the organism can produce more cells in a variety of ways. The growth rate shows an increase that may be arithmetic or geometric.
6. Root elongating at a constant rate is an example of arithmetic growth.
A. True
B. False
Answer: A
Explanation: The simplest expression of arithmetic growth is exemplified by a root elongating at a constant rate. On plotting the length of the organ against the time, a linear curve is obtained.
7. How many phases are generally there is a geometric growth curve?
A. One
B. Two
C. Three
D. Four
Answer: C
Explanation: The geometric growth curve has three phases, namely:
i. Lag phase
ii. Exponential or log phase
iii. Stationary phase.
8. Which of the following curves is a characteristic of all living organisms?
A. Hyperbola
B. Straight line
C. Linear curve
D. Sigmoid curve
Answer: D
Explanation: A sigmoid curve is a characteristic of a living organism growing in a natural environment. It is typical for all cells, tissues and organs of a plant.
9. In how many ways the quantitative comparison between the growth of the living system can be made?
A. Two
B. Three
C. Four
D. Five
Answer: A
Explanation: Quantitative comparison between the growth of a living system can be made in two ways:
i. Absolute growth rate
ii. Relative growth rate
10. What is meant by the absolute growth rate?
A. Measurement of total growth
B. Comparison of total growth
C. Measurement and comparison of total growth per unit time
D. Measurement and comparison of total growth
Answer: C
Explanation: The measurement and comparison of total growth per unit time are called an absolute growth rate. The growth of the given system per unit time expressed on a common basis is called a relative growth rate.
11. Which of the following is not an essential element for the growth of the plant?
A. Water
B. Oxygen
C. Nutrients
D. Carbon-dioxide
Answer: D
Explanation: Carbon dioxide is not an essential element for the growth of the plants as it is a by-product which is released during the respiratory pathway. Water, oxygen and nutrients act as very essential elements for growth pf plants as they help in the developmental processes of plants.
12. Turgidity of cells helps in extension growth.
A. True
B. False
Answer: A
Explanation: Turgidity of cells helps in the extension of growth as the turgor pressure inside these turgid cells helps in maintaining the form and structure of cells and also the soft parts of the plant.
13. Which of the following provides medium for enzymatic activities of the plant?
A. Oxygen
B. Soil
C. Nutrients
D. Water
Answer: D
Explanation: Water provides the medium for enzymatic activities needed for growth in the plants as water is a common medium which is easily available to the plants and most of the enzymes known for the plants can get easily dissolved in the water.
14. Which of the following is essential for the growth of the plants?
A. Optimum Temperature
B. Very high temperature
C. Very humid atmosphere
D. Very low temperature
Answer: A
Explanation: Every plant organism has an optimum temperature range best suited for its growth. Any deviation from this range could be detrimental to the survival of the plant.
15. What is differentiation?
A. When cells only differentiate
B. When cells differentiate and mature to perform specific functions
C. When cells divide
D. When cells mature and die
Answer: B
