Chapter 33, Problem 1TYK

Summary Introduction

Introduction:

Plants are composed of a root system and a shoot system. They perform different, but coordinated functions. The growth of the plants is due to the meristem cells that are of two types: apical meristems and lateral meristems. The meristem cells are undifferentiated, and after division these cells get enlarged, and contribute to the growth of plants.

Answer to Problem 1TYK

Correct answer:

The major difference between the plants and the animals is that animals have a determinate growth, while plants have indeterminate growth.

Explanation of Solution

Explanation for the correct answer:

Option (d) states that animals have a determinate growth, while the plants have indeterminate growth. Determinate growth is defined as the growth that slows down or stops once the organism has reached a certain size. On the contrary, indeterminate growth is defined as the growth that takes place throughout the life, irrespective of one’s size. Most plant species have parts that grow throughout their life, but animals can grow only up to a certain point of time in their life. Hence, option (d) is correct.

Explanation for incorrect answer:

Option (a) states that the growth in plants generally involves an increase in the summation of the number of cells. The growth of plants not only occurs as increase in number of cells, but also as increase in the girth and height of the plant. Meristems consist of undifferentiated actively dividing cells; after division and enlargement they become specialized, and contribute to the increase in the girth and height of the plant. So, it is an incorrect option.

Option (b) states that the cells in the plants remain approximately of the similar size after the cell division, however in animal cells the increase in the size occurs, even after they are formed. After cell division, the animal cells remain almost the same size, whereas the meristem cells of plant divide, and after division they get enlarged and acquires certain specialized function. So, it is an incorrect option.

Option (c) states that woody tissues are formed in the plants during their growth. Dicotyledonous plants that undergo secondary growth (with lateral meristems) form woody tissues; not all plants form woody tissues. So, it is an incorrect option.

Option (e) states that plants can grow only when they are young, while animals tend to exhibit the grow throughout its life-time. Animals have determinate type of growth, that is, they can grow only up to a certain point of time, and up to a certain size and height. Plants have indeterminate type of growth; they can grow throughout their life. So, it is an incorrect option.

Hence, option (a), (b), (c), and (e) are incorrect.

Conclusion

Thus, it can be concluded that most plant species have parts that grow throughout their life, but animals can grow only up to a certain point of time in their life.