Previous year questions: Morphology of Flowering Plants

Previous year questions: morphology of flowering plants

All ten items are from the official NCERT Exemplar Problems in Biology for Class 11. The exemplar does not print marks against individual questions, so the marks shown here follow the section the question is printed in: one mark for a multiple choice item, two marks for a very short answer, three marks for a short answer and five marks for a long answer. Each heading names the exemplar chapter and the question number inside its section. Work each answer before reading the model answer, because the exemplar repeats its vocabulary across items.

Q1 (NCERT Exemplar, 1 mark)

NCERT Exemplar Class 11 Biology, Chapter 5, Multiple Choice Questions, Q1. Arrange the zones seen in a root in vertical section and choose the correct option: root hair zone, zone of meristems, root cap zone, zone of maturation, zone of elongation.

Answer: From the tip upward the order is root cap zone, zone of meristems, zone of elongation, root hair zone and zone of maturation. That corresponds to option (a), C, B, E, A, D. The root cap protects the tip, the meristem divides, elongation lengthens the root, and the root hairs and maturation follow. Read the option against this order and every wrong arrangement becomes obvious. The zones are printed in vertical section, so the tip of the root is the reference point for the whole sequence, and the root cap comes first in any correct list.

Q2 (NCERT Exemplar, 1 mark)

NCERT Exemplar Class 11 Biology, Chapter 5, Multiple Choice Questions, Q2. In a flower arrangement where lateral flowers open acropetally, where on the axis is the youngest bud found?

Answer: The youngest bud sits at the distal end, so option (b) is correct. In acropetal succession the oldest flowers are at the base and the newest ones appear towards the growing tip, which is the distal end of the axis.

Q3 (NCERT Exemplar, 1 mark)

NCERT Exemplar Class 11 Biology, Chapter 5, Multiple Choice Questions, Q4. What name is given to roots that arise from a plant part other than the radicle?

Answer: They are adventitious roots, so option (c) is correct. Tap roots develop from the radicle, fibrous roots replace the short-lived primary root in monocots, and nodular roots are not a separate category in the chapter.

Q4 (NCERT Exemplar, 2 marks)

NCERT Exemplar Class 11 Biology, Chapter 5, Very Short Answer Type Questions, Q2. Write the floral formula of a flower that is bisexual, actinomorphic, pentamerous, with free stamens and a syncarpous superior trilocular ovary with axile placentation.

Answer: The formula is the actinomorphic symbol, followed by the bisexual symbol, then K5 C5 A5 G(3). The plain K5 and C5 show five free sepals and five free petals, the plain A5 shows five free stamens, and the bracket on G(3) shows three carpels fused into one ovary. The trilocular axile ovary is described in words beneath the formula, because the formula records number and fusion rather than placentation. The trilocular ovary with axile placentation belongs in the written description beside the formula.

Q5 (NCERT Exemplar, 2 marks)

NCERT Exemplar Class 11 Biology, Chapter 5, Very Short Answer Type Questions, Q6. Reticulate venation is typical of which group of plants, and parallel venation of which group?

Answer: Reticulate venation is typical of dicotyledonous plants, and parallel venation is typical of monocotyledonous plants. The veins of a reticulate leaf form a network, while the veins of a parallel leaf run side by side along the lamina. The two patterns are useful field characters, though the chapter notes exceptions in both groups. A single vein pattern on a leaf therefore points to the group but does not settle it on its own.

Q6 (NCERT Exemplar, 3 marks)

NCERT Exemplar Class 11 Biology, Chapter 5, Short Answer Type Questions, Q1. Give two examples of roots that arise from a plant part other than the radicle.

Answer: Adventitious roots are the answer. In the banyan tree roots grow down from the branches and act as prop roots, while in Monstera roots arise from the stem and cling to a support. Grass also produces adventitious roots from the base of the stem, and these form the fibrous root system of monocots. The common point is that the radicle is not the source. In an exam answer, name the plant, name the plant part the root grew from, and give the function it performs, because those three details carry the marks.

Q7 (NCERT Exemplar, 3 marks)

NCERT Exemplar Class 11 Biology, Chapter 5, Short Answer Type Questions, Q4. A typical angiosperm flower has four floral parts. Name them and give their sequential arrangement.

Answer: From the outside in the parts are calyx, corolla, androecium and gynoecium. The calyx is made of sepals and the corolla of petals; these two are the accessory whorls. The androecium is made of stamens and the gynoecium of carpels; these two are the reproductive whorls. All four are arranged in successive whorls on the thalamus, with the calyx outermost and the gynoecium in the centre. The two accessory whorls protect the flower and attract pollinators, while the two reproductive whorls make and receive the gametes.

Q8 (NCERT Exemplar, 3 marks)

NCERT Exemplar Class 11 Biology, Chapter 5, Short Answer Type Questions, Q9. How can free central placentation be told apart from axile placentation?

Answer: In free central placentation the ovules sit on a central axis and there are no septa in the ovary, as in Dianthus and primrose. In axile placentation the ovary is divided into chambers, and the ovules attach to an axial placenta where the septa meet, as in china rose, tomato and lemon. A cross-section settles the matter: septa present means axile, septa absent with a central column means free central. The examples are worth pairing with the names, because an examiner can ask the example and the type in either direction. A short table with the type, the position of the placenta and one example covers every version of the item.

Q9 (NCERT Exemplar, 3 marks)

NCERT Exemplar Class 11 Biology, Chapter 5, Short Answer Type Questions, Q11. Why is a maize grain usually called a fruit and not a seed?

Answer: The maize grain has its seed coat fused with the fruit wall, and the two cannot be peeled apart. The covering around the grain is therefore a fruit wall, which makes the whole structure a fruit. Inside, the grain still shows the seed parts: the endosperm, the aleurone layer, the shield-shaped scutellum, the coleoptile over the plumule and the coleorhiza over the radicle. That mix of a fruit wall outside and a seed inside is exactly why the maize grain is described as a fruit that contains a seed. The labels to write are the fused seed coat and fruit wall, the endosperm, the aleurone layer, the scutellum, the coleoptile, the plumule, the radicle and the coleorhiza.

Q10 (NCERT Exemplar, 5 marks)

NCERT Exemplar Class 11 Biology, Chapter 5, Long Answer Type Questions, Q5. Placentation is the way the ovules sit inside the ovary. What does the placenta mean in this context, and which types of placentation are recognised?

Answer: The placenta is the flattened, cushion-like tissue on the inner wall of the ovary to which the ovules are attached. Its position gives the type of placentation. Marginal: the placenta lies as a ridge on the ventral side, with the ovules in two rows, as in pea. Axile: the placenta is axial and the ovules attach in a many-chambered ovary, as in china rose, tomato and lemon. Parietal: the ovules sit on the inner wall, and a false septum makes the ovary two-chambered, as in mustard and Argemone. Free central: the ovules sit on a central axis with no septa, as in Dianthus and primrose. Basal: the placenta sits at the base and carries a single ovule, as in sunflower and marigold. A section of the ovary with the placenta marked is the safest way to draw each type. Label the placenta itself, the ovules and the septa, then the type follows from the picture without memorising the words.