Tag: internal structure of root, stem and leaf

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Questions Related to internal structure of root, stem and leaf

Multiple choice botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root

Bundle sheath cells are similar to mesophyll cells in 
a. Having grana.
b. Having large number of chloroplasts
c. Being involved in $CO _2$ fixation
d. Being impervious to gaseous exchange
e. Their primary $CO _2$ fixation product.

  1. Only c& e

  2. Only c

  3. Only a,b& e

  4. Only a & d
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Bundle sheath cells in C4 plants are involved in the Calvin cycle (CO2 fixation) and are specialized for this purpose, similar to mesophyll cells in C3 plants. They do not have grana (in C4 plants) and are not involved in the initial CO2 fixation (which is done by PEP carboxylase in mesophyll).

Multiple choice botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root

The character of monocot is

  1. Net-veined leaves

  2. Annual rings

  3. Seed with two masses of stored food

  4. Conducting strands scattered in ground tissue
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Net-veined leaves, annual rings and seed with two masses of stored food are characteristic features of dicots. 

In a monocotyledenos, the vascular bundles are not arranged in a circle but are usually scattered throughout the ground tissue. There is no clearly defined pith as there is in many dicotyledonous species. The vascular bundles of monocotylenous plants do not contain a layer of meristematic tissue (cambium) as the dicots do. Thus, no new cells can be formed inside the vascular bundles of monocots and their vascular bundles are termed as closed, whereas those of dicot plants are open. 

Multiple choice botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root

In monocots, root cap is formed by

  1. Dermatogen

  2. Calyptrogen

  3. Wound cambium

  4. Vascular cambium
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Dermatogen is the histogen or meristematic regions of root and stem which is produced by apical meristem and give rise to uniseriate epidermis by anticlinal divisions; option A is incorrect. Monocotyledons have one additional histogen along with dermatogens, periblem and plerome Calyptrogen being the fourth one that makes root cap. The vascular cambium, also called as wood cambium, has thin walled highly vacuolated cells of two types, the fusiform initials and the ray initials. The fusiform initials are the elongated cells that give rise to secondary xylem and secondary phloem. Ray initials are horizontally organized and produce vascular rays (medullary rays or ray parenchyma). 

Thus, the correct answer is option B.

Multiple choice botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root

Monocot root differs from dicot root in having

  1. Open vascular bundle

  2. Scattered vascular bundle

  3. Large pith

  4. No pit
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Pith is the innermost region of the root representing the central axis. It is composed of few loosely arranged parenchyma cells. Large pith is present in monocot roots. In dicot roots, pith is absent. Open vascular bundles are present in dicots. Scattered vascular bundles are present in moncot stem. Radial vascular bundles are present in both monocot and dicot roots.

Thus, the correct answer is option C.

Multiple choice botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root

Polyarch and exarch vascular bundles are the characteristic of

  1. Dicot stem

  2. Dicot root

  3. Monocot stem

  4. Monocot root
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Monocot root vascular bundles are radial in arrangement. There are eight bundles each of xylem and phloem. Hence, the condition is described as polyarch. Xylem is described as exarch in them. 

Monocot stem vascular bundles are conjoint, collateral and closed. Xylem is endarch in them. Presence of only two protoxylem and two metaxylem vessels in each bundle. 
Dicot root vascular bundles are described as radial and tetrarch. There are four bundles each of xylem and phloem occurring alternately. Xylem is described as exarch. 
Dicot stem vascular bundles are eight in number, arranged in form of a broken ring. The vascular bundles are conjoint, collateral and open. Xylem is on the inner surface and phloem on the outer surface. Xylem is described as endarch. Thus, option D is correct.

Multiple choice botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root

Which of the following is correct sequence of layers in typical monocot root from outside to inside?

  1. Pericycle, cortex, endodermis, epiblema

  2. Epiblema, endodermis, cortex, pericycle

  3. Epiblema, cortex, endodermis, pericycle

  4. Epiblema, pericycle, cortex, endodermis
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The sequence of layers in typical monocot root from outer surface to inside is epiblema, cortex, endodermis, stele, pericycle, conjunctive tissue, pith and vascular bundles. Thus, option C is correct.

Multiple choice botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root

Passage cells are more distinct in endodermis of

  1. Dicot stem

  2. Monocot stem

  3. Dicot root

  4. Monocot root
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Passage cells are endodermal cells of older monocot roots which have retained thin walls and Casparian strips rather than becoming suberized and waterproof like the other cells around them, to continue to allow some symplastic flow to the inside. Experimental evidence suggests that passage cells function to allow transfer of solutes such as calcium and magnesium into the stele, in order to eventually reach the transpiration system. For the most part, however, old roots seal themselves off at the endodermis, and only serve as a passageway for water and minerals taken up by younger roots "downstream". Passage cells are absent in dicot roots, monocot stem and dicot stem.

Therefore, the correct answer is option D.

Multiple choice botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root

Passage cells are found in

  1. Monocot root

  2. Monocot stem

  3. Aerial root

  4. Dicot stem
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Passage cells are endodermal cells of older roots which have retained thin walls and Casparian strips rather than becoming suberized and waterproof like the other cells around them, to continue to allow some symplastic flow to the inside. Passage cells function to allow transfer of solutes, such as calcium and magnesium into the stele, in order to eventually reach the transpiration system. 

Multiple choice botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root

Exarch and polyarch xylem strands are found in

  1. Monocot stem

  2. Dicot stem

  3. Monocot root

  4. Dicot root
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In monocot root vascular bundles are radial in arrangement. There are eight bundles each of xylem and phloem. Hence, the condition is described as polyarch. Xylem is described as exarch in monocot root.