Structural Organisation in Plants is a Botany chapter in the NEET (UG) syllabus. NEET720 has 120 reviewed practice questions on it, each with a quick answer and a step-by-step explanation. The 8 questions below are free and fixed, so you can bookmark this page; the full chapter, plus mistake tracking and spaced revision, is in the app.
19
easy
65
medium
36
hard
Topics covered
Root system · Root modifications · Stem modifications · Leaf structure · Leaf modifications · Root anatomy · Stem anatomy · Leaf anatomy · Tissue systems · Meristem classification · Simple tissues · Xylem and phloem components · Stomatal structure · Epidermal appendages · Vascular bundle types · Leaf phyllotaxy · Complex tissues · Anomalous secondary growth · Wood anatomy · Leaf types · Inflorescence types · Stomatal apparatus · Wood classification · Leaf apex and margin · Stomatal types · Stem structure · Morphology - Root · Morphology - Stem · Morphology - Leaf · Morphology - Flower · Morphology - Family characteristics · Morphology - Seed · Anatomy - Tissue systems · Anatomy - Simple tissues · Anatomy - Complex tissues · Anatomy - Root · Anatomy - Stem · Anatomy - Leaf · Morphology - Inflorescence · Morphology - Fruit
8 free Structural Organisation in Plants practice questions with answers
Choose an answer in your head before opening it. Each explanation says why the correct option is right and, where relevant, why the tempting wrong option is wrong.
Question 1 · easy · Root
The root cap present at the tip of a growing root primarily functions to:
- A.Protect the delicate apical meristem as the root pushes through the soil
- B.Absorb water and mineral nutrients from the soil
- C.Store food reserves such as starch for the entire plant
- D.Conduct photosynthesis to supplement the plant's food production
Show answer and explanation
Answer: A. Protect the delicate apical meristem as the root pushes through the soil
The root cap is a thimble-like structure covering the tip of the root that protects the tender, actively dividing apical meristem as the root grows through the soil.
The root tip is covered by a thimble-like structure called the root cap, which protects the tender apex of the root as it makes its way through the soil. The root cap cells are continuously sloughed off due to friction with soil particles and are replaced by new cells produced by the apical meristem, ensuring ongoing protection during root elongation. This differs from the absorption function of root hairs and the storage or photosynthetic functions of other plant regions.
Common mistake: Confusing the protective role of the root cap with the absorptive function carried out by root hairs.
Question 2 · medium · Root
Mangrove plants growing in swampy, oxygen-deficient saline habitats, such as Rhizophora, develop specialised vertical root outgrowths called pneumatophores. The primary function of these structures is to:
- A.Rise above the mud/water surface to facilitate the exchange of gases, particularly the uptake of atmospheric oxygen for respiration
- B.Absorb additional water from the surrounding swamp to compensate for a dry habitat
- C.Anchor the plant more firmly by penetrating deep into the substratum, unlike normal roots
- D.Store large quantities of starch as a food reserve for the plant
Show answer and explanation
Answer: A. Rise above the mud/water surface to facilitate the exchange of gases, particularly the uptake of atmospheric oxygen for respiration
Pneumatophores are negatively geotropic root structures that grow upward out of the waterlogged, oxygen-poor mud, allowing atmospheric oxygen to reach the underground root system through pores called pneumathodes.
In plants growing in swampy areas, particularly mangroves such as Rhizophora that inhabit oxygen-deficient waterlogged soil, many roots come out of the ground and grow vertically upwards, an adaptation called pneumatophores. These structures possess numerous pores, called pneumathodes, that allow the exchange of gases, helping the plant obtain adequate oxygen for cellular respiration despite growing in an anaerobic substrate.
Common mistake: Assuming pneumatophores serve for extra water absorption or anchorage rather than gas exchange in oxygen-poor soils.
Question 3 · medium · Stem
In plants such as Opuntia (prickly pear) growing in arid conditions, the green, flattened, photosynthetic structure that appears leaf-like but is actually derived from the stem is called a:
- A.Phylloclade
- B.Phyllode
- C.Cladode restricted only to a single internode with no further branching capacity
- D.Rhizome
Show answer and explanation
Answer: A. Phylloclade
In Opuntia, the stem itself becomes green, flattened and fleshy, taking over the function of photosynthesis in the near-absence of leaves (which are reduced to spines); this modified stem is called a phylloclade.
In areas where rainfall is scanty, stems are often modified to store water and carry out photosynthesis, and leaves are reduced to spines to minimise water loss through transpiration. In Opuntia, the stem is modified into a flattened, green, fleshy structure called a phylloclade, which performs photosynthesis in place of the reduced leaves. This differs from a phyllode (a modified petiole, as in Australian Acacia) and a rhizome (an underground perennating stem, as in ginger).
Common mistake: Confusing a phylloclade (stem-derived) with a phyllode (petiole-derived) despite both serving a similar photosynthetic function.
Question 4 · medium · Leaf
In plants such as Nerium, where three leaves arise at each node and are arranged in a whorl around the stem, this pattern of leaf arrangement is termed:
- A.Whorled phyllotaxy
- B.Alternate phyllotaxy
- C.Opposite phyllotaxy
- D.Radical phyllotaxy with no defined nodal pattern
Show answer and explanation
Answer: A. Whorled phyllotaxy
When more than two leaves arise at a node and are arranged in a whorl, as in Nerium (with three leaves per node), the arrangement is called whorled phyllotaxy.
The pattern of arrangement of leaves on the stem or branch is called phyllotaxy, and it is generally of three types: alternate (a single leaf arises at each node alternately, as in China rose, mustard and sunflower), opposite (a pair of leaves arises at each node and lies opposite to each other, as in Calotropis and guava), and whorled (when more than two leaves arise at a node and form a whorl, as in Alstonia and Nerium, where three leaves arise per node).
Common mistake: Confusing whorled phyllotaxy (more than two leaves per node) with opposite phyllotaxy (exactly two leaves per node).
Question 5 · easy · Leaf
In a typical dicotyledonous leaf, such as that of China rose, the veins and veinlets are usually arranged forming a network. This pattern of venation is called:
- A.Reticulate venation
- B.Parallel venation
- C.Radiate venation with veins arising from a single central point only, with no network formation
- D.Uniform venation with only a single vein running the length of the leaf
Show answer and explanation
Answer: A. Reticulate venation
Reticulate venation, in which veins and veinlets form an irregular network, is characteristic of most dicotyledonous leaves, in contrast to the parallel venation typical of monocots.
The arrangement of veins in a leaf lamina is termed venation. When the veins and veinlets are irregularly distributed, forming a network, it is called reticulate venation, and this is generally found in dicotyledonous plants, such as China rose. When the veins run parallel to each other within a lamina, it is called parallel venation, and this is generally found in monocotyledonous plants, such as banana and wheat.
Common mistake: Reversing the association, assuming reticulate venation is characteristic of monocots rather than dicots.
Question 6 · medium · Inflorescence
In a racemose type of inflorescence, the main axis continues to grow and produces flowers laterally in an acropetal succession. This means that:
- A.The oldest flowers are located towards the base of the axis, and the youngest flowers are found towards the tip
- B.The oldest flowers are located towards the tip of the axis, and the youngest flowers are found towards the base
- C.All flowers on the axis open simultaneously with no age difference at all
- D.The main axis terminates in a flower, ending its own further growth
Show answer and explanation
Answer: A. The oldest flowers are located towards the base of the axis, and the youngest flowers are found towards the tip
In racemose inflorescences, the main axis grows continuously (indefinite growth) and produces flowers laterally in acropetal succession, meaning older flowers are near the base and younger ones near the growing tip.
Inflorescences are broadly classified as racemose or cymose based on the pattern of flower arrangement on the floral axis. In the racemose type, the main axis continues to grow, and flowers are borne laterally in an acropetal succession — the oldest flowers are situated towards the base (or outermost, in a flat-topped inflorescence) while the youngest flowers are situated towards the apex. This is in contrast to the cymose type, where the main axis terminates in a flower (limiting further growth of the main axis), and the flowers are arranged in a basipetal order, with the youngest flower at the base and the oldest at the tip.
Common mistake: Reversing the age gradient, confusing the acropetal pattern of racemose inflorescences with the basipetal pattern of cymose inflorescences.
Question 7 · hard · Flower
In the flower of China rose (Hibiscus rosa-sinensis), the petals overlap one another, but not in any particular direction. This mode of arrangement of sepals or petals in a flower bud is termed:
- A.Twisted aestivation
- B.Valvate aestivation
- C.Imbricate aestivation with margins overlapping only at specifically defined, non-twisted margins
- D.Vexillary aestivation
Show answer and explanation
Answer: A. Twisted aestivation
In China rose, the aestivation is twisted, in which one margin of the petal overlaps the next one and its other margin is overlapped by the preceding petal, forming a distinctive twisted pattern.
Aestivation refers to the pattern of arrangement of sepals or petals in a flower bud relative to other members of the same whorl. In China rose, the aestivation is described specifically as twisted, in which one margin of a given petal overlaps the margin of the next petal, and this margin, in turn, is overlapped by the margin of the preceding petal, resulting in a consistent, directional twisted arrangement. This is distinct from valvate aestivation (margins merely touching, as in Calotropis), general imbricate aestivation (margins overlap without a fixed directional pattern, as in Cassia and gulmohar), and vexillary aestivation (specific to pea-family flowers).
Common mistake: Confusing twisted aestivation (a directional, consistent overlap) with general imbricate aestivation (overlap without a fixed direction) or valvate aestivation (no overlap at all).
Question 8 · medium · Flower
In a typical pea pod (family Fabaceae), the ovules are attached along the ventral suture of a single carpel forming a single row. This arrangement of ovules within the ovary is called:
- A.Marginal placentation
- B.Axile placentation
- C.Parietal placentation
- D.Free central placentation
Show answer and explanation
Answer: A. Marginal placentation
In marginal placentation, seen in the pea pod, the placenta forms a ridge along the ventral suture of the ovary, and the ovules are borne on this ridge, forming a single row.
Placentation refers to the pattern of ovule arrangement within the ovary. In marginal placentation, the placenta forms a ridge along the ventral suture of the ovary, and the ovules are borne on this ridge, forming two rows, as commonly seen in pea, a member of family Fabaceae. This differs from axile placentation (China rose, tomato), parietal placentation (mustard, Argemone), and free central placentation (Dianthus, Primrose).
Common mistake: Confusing marginal placentation (single carpel, ventral suture) with axile or parietal placentation, which involve different carpel numbers and ovary structures.
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Questions about Structural Organisation in Plants for NEET
How many NEET questions does NEET720 have on Structural Organisation in Plants?＋
NEET720 has 120 reviewed practice questions on Structural Organisation in Plants (Botany): 19 easy, 65 medium and 36 hard. 8 of them are free on this page with full explanations; the rest are available in the app.
Is Structural Organisation in Plants a Class 11 or Class 12 chapter for NEET?＋
Structural Organisation in Plants spans topics from both Class 11 and Class 12 Botany as grouped in NEET720's bank. Read the relevant NCERT chapters first, then practise chapter-wise MCQs and previous-year questions.
How should I practise Structural Organisation in Plants for NEET?＋
Attempt the questions below without looking at the options for more than a few seconds, mark your answer, then read the explanation even when you were right. Record every mistake and revisit it after a gap. On NEET720 this happens automatically: wrong answers go to your Mistake Book and are scheduled for spaced revision.
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Questions are original NEET720 compositions reviewed for correctness, syllabus fit and option quality. Counts update as the bank grows (120 active practice questions in this chapter today).