Plant Tissues and Reproduction – NDA Biology PYQs

NDA 2026-I

Q. 1. Which one of the following tissues in plants is usually without protoplast and regarded as dead cells?

(a) Collenchyma

(b) Parenchyma

(c) Sclerenchyma

(d) Xylem parenchyma

Answer: (c) Sclerenchyma

Explanation: Sclerenchyma cells are dead at maturity: they lose their protoplast (living contents) and become heavily lignified. Their thick secondary cell walls provide mechanical support and rigidity to the plant. Types include sclerenchyma fibres (long cells) and sclereids (short, irregularly shaped cells). Collenchyma and parenchyma are living tissues with protoplasts. Xylem parenchyma retains its protoplast. Concept Tested: Sclerenchyma: dead cells (no protoplast) with thick lignified walls; provide mechanical support

★ JOVIK Exam Insight Tissue classification by living vs. dead cells: Parenchyma = living, thin walls, basic packing tissue. Collenchyma = living, unevenly thickened walls, flexibility. Sclerenchyma – dead, heavily lignified walls, mechanical support. Among permanent tissues, sclerenchyma is the only one whose cells are dead at maturity.

Q. 2. Which part of the plant or flower contributes in the form of false fruit like apple?

(a) Petal

(b) Sepal

(c) Stamen

(d) Thalamus

Answer: (d) Thalamus

Explanation: In a true fruit, only the ovary wall (pericarp) develops into the fruit. In a false fruit (pseudocarp), other floral parts also contribute to the fleshy edible portion. In apple, the thalamus (receptacle: the swollen base of the flower) becomes the fleshy edible part. The actual fruit (derived from ovary) is the core containing the seeds. This is why apple is a false fruit: most of what we eat is thalamus, not ovary. Concept Tested: Apple is a false fruit: the edible fleshy part is the thalamus (receptacle), not the ovary

Q. 3. Which one of the following parts of an ovule possesses reserve food?

(a) Integument

(b) Funicle

(c) Chalaza

(d) Nucellus

Answer: (d) Nucellus

Explanation: The nucellus is the central tissue of an ovule that surrounds the embryo sac. It is a nutritive tissue: it stores food reserves that nourish the developing embryo before and after fertilisation. Integuments are the outer protective layers (become the seed coat/testa after fertilisation). The funicle is the stalk attaching the ovule to the placenta. The chalaza is the base region where the integuments merge with the nucellus. Concept Tested: Nucellus: the nutritive tissue of the ovule that stores food reserves

 NDA 2025-I

Q. 4. Cambium is an example of

(a) Lateral meristem

(b) Apical meristem

(c) Intercalary meristem

(d) Permanent tissue

Answer: (a) Lateral meristem

Explanation: Cambium is a lateral meristem: a meristematic tissue located along the sides (lateral margins) of plant organs. It is responsible for secondary growth: increasing the girth (diameter) of stems and roots. There are two types: vascular cambium (produces secondary xylem and phloem) and cork cambium (produces bark/periderm). Apical meristems are at shoot and root tips. Intercalary meristems are found at the base of internodes (in grasses). Concept Tested: Cambium – lateral meristem; responsible for secondary growth (increase in girth)

 NDA 2024-II

Q. 5. In which one among the following the vegetative propagation takes place through Eye Buds?

(a) Potato

(b) Ginger

(c) Onion

(d) Sugarcane

Answer: (a) Potato

Explanation: Potato is a modified underground stem (tuber). Its surface has small pit-like structures called ‘eyes,’ which are the nodes containing axillary buds. These eye buds can sprout and develop into new plants: a form of vegetative propagation. Ginger propagates through rhizomes (modified underground stems, but not through ‘eye buds’). Onion propagates through bulbs. Sugarcane propagates through stem cuttings. Concept Tested: Potato propagates vegetatively through ‘eye buds’ (axillary buds on the tuber surface)

 NDA 2023-II

Q. 6. In angiosperms, pollen grain germinates to produce two male gametes. Which one of the following functions is carried out by these gametes?

(a) Both the gametes fuse with a single egg cell

(b) Both the gametes fuse with two different egg cells

(c) One gamete fuses with the egg cell and the other one eventually degenerate

(d) One gamete fuses with the egg cell and the other one fuses with a diploid secondary nucleus

Answer: (d) One gamete fuses with the egg cell and the other one fuses with a diploid secondary nucleus

Explanation: This is the process of double fertilization: a unique feature of angiosperms. One male gamete (n) fuses with the egg cell (n) to form the zygote (2n), which develops into the embryo. The second male gamete (n) fuses with the diploid secondary nucleus (2n, formed by the fusion of two polar nuclei) to form the primary endosperm nucleus (3n). This endosperm (3n) nourishes the developing seed. Concept Tested: Double fertilization in angiosperms: one gamete + egg → zygote (2n); other gamete + secondary nucleus → endosperm (3n)

★ JOVIK Exam Insight Double fertilization is a defining feature of angiosperms (flowering plants). Key outcomes: Zygote (2n) → embryo. Primary endosperm nucleus (3n) → endosperm (food for seed). The secondary nucleus is diploid (2n – two polar nuclei fused). Gamete (n) + secondary nucleus (2n) – 3n endosperm.

Q. 7. Relationship between a flower and honey-bee will help the flower for/in

(a) Faster development

(b) Pollination

(c) Quick germination of pollen

(d) Increase in size

Answer: (b) Pollination

Explanation: Honey-bees visit flowers to collect nectar. While doing so, pollen grains from the flower’s anthers stick to the bee’s body. When the bee visits another flower of the same species, the pollen is deposited on that flower’s stigma. This is pollination: the transfer of pollen from anther to stigma. The relationship between bee and flower is mutualistic: the bee gets nectar, and the flower gets pollinated. Concept Tested: Honey-bee and flower relationship enables pollination (pollen transfer from anther to stigma)

Q. 8. In flowering plants, DNA content of the parent plant gets halved during

(a) Seed germination

(b) Fruit formation

(c) Flower bud formation

(d) Pollen formation

Answer: (d) Pollen formation

Explanation: The DNA content of a cell is halved during meiosis, which reduces the chromosome number from diploid (2n) to haploid (n). In flowering plants, meiosis occurs during the formation of pollen grains (microspores) from pollen mother cells in the anther, and during the formation of megaspores in the ovule. Pollen grain formation therefore halves the DNA content. Seed germination, fruit formation, and flower bud formation do not involve meiosis. Concept Tested: DNA content halved during pollen formation (meiosis in pollen mother cells of the anther)

Q. 9. Which one of the following is the correct sequence during sexual reproduction in Angiosperms?

(a) Egg → zygote → embryo → seed

(b) Embryo → egg → zygote → seed

(c) Egg → embryo → zygote → seed

(d) Egg → seed → zygote → embryo

Answer: (a) Egg → zygote → embryo → seed

Explanation: The correct sequence in angiosperm sexual reproduction is: Egg (female gamete in ovule) → fertilisation by male gamete → Zygote (2n) → cell division and development → Embryo → mature → Seed (containing embryo within seed coat, derived from ovule). Option (a) correctly represents this sequence. Concept Tested: Angiosperm reproductive sequence: egg → zygote → embryo → seed

Q. 10. Which one of the following combinations of events represents the correct sequence during reproduction in flowering plants?

(a) Ovule → fruit; egg → embryo; zygote → seed; ovary → egg

(b) Embryo → egg; ovary → fruit; ovule → zygote; zygote → seed

(c) Ovary → fruit; zygote → egg; embryo → ovule; seed → fruit

(d) Egg → zygote; zygote → embryo; ovule → seed; ovary → fruit

Answer: (d) Egg → zygote; zygote → embryo; ovule → seed; ovary → fruit

Explanation: The correct developmental sequence in flowering plants: Egg + sperm → Zygote (fertilisation). Zygote divides → Embryo develops. Ovule (containing embryo and endosperm) matures into → Seed. Ovary wall matures into → Fruit (pericarp). Option (d) correctly maps all four transformations. Concept Tested: Post-fertilisation development: egg→zygote; zygote→embryo; ovule→seed; ovary→fruit

 NDA 2022-II

Q. 11. After fertilization, the fruit and the seed are produced by

(a) ovule and ovary, respectively

(b) ovary and ovule, respectively

(c) ovary, no ovule required

(d) ovule, no ovary required

Answer: (b) ovary and ovule, respectively

Explanation: After fertilisation in flowering plants: the ovary (surrounding structure) develops into the fruit: specifically the pericarp (fruit wall). The ovule (containing the fertilised egg) develops into the seed. This is why option (b) is correct: fruit is from ovary, seed is from ovule. The ovary wall becomes the fruit’s flesh/pericarp, and the ovule’s integuments become the seed coat (testa). Concept Tested: After fertilisation: ovary → fruit; ovule → seed

 NDA 2022-I

Q. 12. In aquatic plants, large air sacs give them buoyancy effects. These sacs are surrounded by which one of the following types of tissues?

(a) Parenchyma

(b) Collenchyma

(c) Sclerenchyma

(d) Complex tissue

Answer: (a) Parenchyma

Explanation: The air sacs (aerenchyma) in aquatic plants are large air-filled intercellular spaces. These spaces are enclosed by parenchyma cells: the basic, thin-walled living cells that make up the fundamental tissue of plants. Parenchyma cells can be loosely arranged, creating large intercellular spaces that fill with air, giving aquatic plants their buoyancy. This modified form of parenchyma with large air cavities is called aerenchyma. Concept Tested: Air sacs (aerenchyma) in aquatic plants are surrounded by parenchyma cells

Q. 13. Which one of the following plants has unisexual flowers?

(a) Papaya

(b) Hibiscus

(c) Mustard

(d) Sunflower

Answer: (a) Papaya

Explanation: Unisexual flowers (imperfect flowers) have either only stamens (male) or only carpels (female): not both. Papaya is a classic example of a plant with unisexual flowers: the male and female flowers are borne on separate plants (dioecious). Hibiscus, mustard, and sunflower all have bisexual (perfect) flowers that contain both stamens and carpels. Concept Tested: Papaya has unisexual (imperfect) flowers; hibiscus, mustard, and sunflower have bisexual flowers

 NDA 2021-II

Q. 14. Which one of the following tissues is known as basic packing tissue and found in xylem and phloem?

(a) Collenchyma

(b) Parenchyma

(c) Sclerenchyma

(d) Vessels

Answer: (b) Parenchyma

Explanation: Parenchyma is the basic packing (ground) tissue of plants. It consists of thin-walled, living cells with large vacuoles. Parenchyma is found embedded within both xylem (as xylem parenchyma) and phloem (as phloem parenchyma). It fills spaces between other cells, stores food and water, and can differentiate into other cell types. Collenchyma provides flexible support. Sclerenchyma provides rigid support. Vessels are part of xylem for water transport. Concept Tested: Parenchyma: basic packing tissue present in xylem and phloem; living, thin-walled cells

Q. 15. Girth of stem of a plant increases due to division of cells in

(a) apical meristem only.

(b) lateral meristem only.

(c) apical and intercalary meristem.

(d) both apical and lateral meristem.

Answer: (b) lateral meristem only.

Explanation: The girth (diameter/thickness) of a plant stem increases through secondary growth, which is produced by the lateral meristem: specifically the vascular cambium (which produces secondary xylem and phloem) and the cork cambium (which produces bark). Apical meristems are responsible for elongation (increase in length), not girth. Intercalary meristems are found in grasses and cause elongation of internodes, not girth increase. Concept Tested: Girth increase in plant stems – lateral meristem (cambium); apical meristem – length increase

 NDA 2021-I

Q. 16. Transformation of meristematic cells into specific permanent tissues occurs by the process of

(a) Cell differentiation.

(b) Cell division.

(c) Cell multiplication.

(d) Cell regeneration.

Answer: (a) Cell differentiation.

Explanation: Meristematic cells are undifferentiated, actively dividing cells. When they stop dividing and take on specific structures and functions to form permanent tissues (parenchyma, collenchyma, sclerenchyma, xylem, phloem), this process is called cell differentiation. Differentiation involves changes in cell shape, size, wall composition, and metabolic activities. Cell division is what meristematic cells do before differentiation. Regeneration is repair of damaged tissue. Concept Tested: Cell differentiation: meristematic cells transform into specific permanent tissues

Q. 17. During seed germination, the part of the embryo which grows into root is

(a) Radicle.

(b) Plumule.

(c) Cotyledon.

(d) Epicotyl.

Answer: (a) Radicle.

Explanation: During seed germination, the radicle is the embryonic root: it is the first part to emerge from the seed and grows downward into the soil to form the primary root system. The plumule is the embryonic shoot that grows upward to form the stem and leaves. Cotyledons are the seed leaves that store food (in dicots) or absorb food from endosperm (in monocots). The epicotyl is the part of the embryo above the cotyledon attachment point. Concept Tested: Radicle: embryonic root that develops into the root system during seed germination

Q. 18. In a typical flower, germinating pollen grains pass through several parts of the gynoecium before they reach the ovule. A list of the parts of gynoecium is given below in different combinations. Choose the combination that represents the correct sequence of pollen tube pathway/journey:

(a) Style, Stigma, Ovary

(b) Stigma, Style, Ovary

(c) Pistil, Stigma, Ovary

(d) Ovary, Pistil, Style

Answer: (b) Stigma, Style, Ovary

Explanation: After a pollen grain lands on the stigma (sticky tip of the carpel), it germinates and grows a pollen tube down through the style (elongated column connecting stigma to ovary) and into the ovary, where it reaches the ovule. The correct sequence is: Stigma → Style → Ovary. Option (b) correctly states this order. Concept Tested: Pollen tube pathway: Stigma → Style → Ovary (→ ovule)

 NDA 2020

Q. 19. Which one of the following plant tissues has dead cells?

(a) Epidermis

(b) Parenchyma

(c) Collenchyma

(d) Sclerenchyma

Answer: (d) Sclerenchyma

Explanation: Among the simple permanent tissues listed, only sclerenchyma has dead cells. Sclerenchyma cells are heavily lignified, rigid, and have no living protoplast at maturity. They provide mechanical strength. Epidermis cells are living (though the cuticle is non-living). Parenchyma cells are living and thin-walled. Collenchyma cells are living with unevenly thickened walls. Concept Tested: Sclerenchyma has dead cells (no protoplast) at maturity; all other listed tissues are living

 NDA 2019-II

Q. 20. Which one of the following statements is correct?

(a) Xylem consists of tracheids, vessels, xylem parenchyma and xylem fibres.

(b) Flexibility in plants is due to sclerenchyma.

(c) Parenchyma have no intercellular spaces.

(d) Xylem consists of sieve plate, sieve tube and companion cells.

Answer: (a) Xylem consists of tracheids, vessels, xylem parenchyma and xylem fibres.

Explanation: Option (a) is correct: xylem is composed of four types of cells: tracheids (elongated dead cells for water transport), vessels (tube-like dead cells for water transport), xylem parenchyma (living, for storage and lateral transport), and xylem fibres (dead, for mechanical support). Option (b) is wrong: flexibility is due to collenchyma, not sclerenchyma. Option (c) is wrong: parenchyma typically has well-defined intercellular spaces. Option (d) describes phloem components, not xylem. Concept Tested: Xylem components: tracheids, vessels, xylem parenchyma, xylem fibres; sieve tubes and companion cells are phloem

★ JOVIK Exam Insight NDA tests xylem vs. phloem composition. Xylem: tracheids, vessels, xylem parenchyma, xylem fibres (all dead except xylem parenchyma). Phloem: sieve tubes, companion cells, phloem parenchyma, phloem fibres (all living except phloem fibres). Never confuse sieve tubes with xylem.

 NDA 2019-I

Q. 21. Which one of the following is NOT a component of conducting tissue in plants?

(a) Fibres

(b) Tracheids

(c) Pericycle

(d) Sieve tubes

Answer: (c) Pericycle

Explanation: The conducting (vascular) tissues in plants are xylem and phloem. Fibres are found in both xylem and phloem. Tracheids are conducting elements of xylem. Sieve tubes are conducting elements of phloem. The pericycle is NOT a conducting tissue: it is a layer of cells between the endodermis and the vascular bundles in roots. It plays a role in lateral root formation and is part of the ground tissue. Concept Tested: Pericycle is not a conducting tissue; it is ground tissue in roots; xylem and phloem are the conducting tissues

 NDA 2018-II

Q. 22. Damage to the apical meristem of a growing young plant will affect the

(a) length of the plant

(b) colour of the flower

(c) colour of the leaves

(d) taste of the fruits

Answer: (a) length of the plant

Explanation: The apical meristem is located at the tip of shoots and roots. It is responsible for primary growth: the elongation and increase in length of the plant. Damage to the apical meristem halts this elongation. The plant will not grow taller. Flower colour, leaf colour, and fruit taste are not directly determined by the apical meristem: they depend on pigments, genes, and ripening processes. Concept Tested: Apical meristem controls plant length (primary growth/elongation); damage stops height increase

Q. 23. If one set of chromosomes for a given plant is represented as N; in case of double fertilization, the zygote and the endosperm nucleus of a diploid plant would have how many sets of chromosomes respectively?

(a) N and 2N

(b) 2N and 2N

(c) N and 3N

(d) 2N and 3N

Answer: (d) 2N and 3N

Explanation: A diploid plant has 2N chromosomes. During meiosis, egg cell = N. Male gamete = N. Double fertilisation: Zygote = egg (N) + male gamete (N) = 2N. Secondary nucleus = two polar nuclei = N + N = 2N. Endosperm nucleus = secondary nucleus (2N) + male gamete (N) = 3N. Therefore zygote = 2N and endosperm = 3N. Concept Tested: Double fertilisation: zygote = 2N (egg N + sperm N); endosperm = 3N (secondary nucleus 2N + sperm N)

 NDA 2018-I

Q. 24. Which one of the following statements about meristematic tissues in plants is correct?

(a) These are dead tissues and form wood

(b) They provide flexibility to plant due to their thickened walls

(c) These are present in the bark of a tree only

(d) Growth occurs in plants due to division of cells of these tissues

Answer: (d) Growth occurs in plants due to division of cells of these tissues

Explanation: Meristematic tissues are living, actively dividing cells responsible for plant growth. Option (d) is correct: all growth in plants results from the division of meristematic cells. Option (a) is wrong: meristematic cells are living, not dead (dead tissues would be sclerenchyma or mature xylem). Option (b) is wrong: flexibility is from collenchyma, not meristematic tissue. Option (c) is wrong: meristems are found at shoot tips, root tips, and along the sides (cambium): not only in bark. Concept Tested: Meristematic tissue: living, actively dividing cells responsible for plant growth

 NDA 2017-I

Q. 25. The colourful part of the Sunflower or Marigold plant is

(a) Flower

(b) Inflorescence

(c) Fruit

(d) Seed

Answer: (b) Inflorescence

Explanation: What appears to be a single large ‘flower’ in sunflower and marigold is actually an inflorescence: a cluster of many small individual flowers (florets) packed together on a common receptacle. The large colourful ‘petals’ around the edge are actually ray florets, and the central disc is made of disc florets. This type of inflorescence is called a capitulum (head). Each floret is a complete small flower. So the colourful part is an inflorescence, not a single flower. Concept Tested: Sunflower/Marigold ‘flower’ is actually an inflorescence (capitulum): a cluster of many florets

 NDA 2015-I

Q. 26. Gametophytes of sexually reproducing flowering plants are

(a) Haploid

(b) Diploid

(c) Tetraploid

(d) Polyploid

Answer: (a) Haploid

Explanation: The gametophyte generation in the plant life cycle refers to the haploid (n) generation that produces gametes. In angiosperms (flowering plants), the gametophyte is highly reduced: the female gametophyte (embryo sac) has 7 cells and 8 nuclei; the male gametophyte is the pollen grain with 2 cells. Both are haploid (n). The sporophyte (the main plant body we see) is diploid (2n). Concept Tested: Gametophytes in flowering plants are haploid (n); the main plant body (sporophyte) is diploid (2n)

Q. 27. The seeds of flowering plants are made up of

(a) Ovary and ovary wall

(b) Embryo, food reserves and coat

(c) Cotyledons

(d) Zygotes

Answer: (b) Embryo, food reserves and coat

Explanation: A seed is a mature ovule containing three main components: the embryo (developed from the zygote: the future plant), food reserves (either in the endosperm or in the cotyledons, providing nourishment for germination), and the seed coat (testa: developed from the integuments of the ovule, which protects the seed). Together, these three constitute the seed. The ovary wall becomes the fruit, not the seed. Concept Tested: Seed composition: embryo + food reserves (endosperm/cotyledons) + seed coat (testa)

 NDA 2013-I

Q. 28. Consider the following statements in relation to plant tissue ‘chlorenchyma’:

1. It is formed by the palisade and spongy mesophyll.

2. It is a form of parenchyma which contains chloroplasts.

3. It serves to transport organic solutes made by photosynthesis.

4. It is a thin transparent layer which has chiefly a protective function.

Which of the statements given above is/are correct?

(a) 1 and 2 only

(b) 1, 2 and 3

(c) 2 and 4

(d) 1 only

Answer: (a) 1 and 2 only

Explanation: Statement 1 is correct: chlorenchyma is the green photosynthetic tissue forming the mesophyll (both palisade and spongy layers) of the leaf. Statement 2 is correct: chlorenchyma is a specialised form of parenchyma containing chloroplasts: it is the modification that makes parenchyma photosynthetic. Statement 3 is incorrect: transport of organic solutes (sugars) is done by phloem, not by chlorenchyma. Statement 4 is incorrect: the thin transparent protective layer is the epidermis, not chlorenchyma. Concept Tested: Chlorenchyma: modified parenchyma with chloroplasts; forms palisade and spongy mesophyll; not for transport or protection

Q. 29. Which of the following statements about sexual reproduction in flowering plants are correct?

1. Stamen is present in the centre of a flower.

2. Stamen produces pollen grains in the ovary.

3. The swollen bottom part of carpel is the ovary.

4. The fusion of germ cells gives rise to zygote.

Select the correct answer using the code given below.

(a) 2, 3 and 4 only

(b) 2 and 4 only

(c) 1 and 3 only

(d) 1, 2, 3 and 4

Answer: (b) 2 and 4 only

Explanation: Statement 1 is incorrect: the carpel/pistil is in the centre of a bisexual flower; stamens surround it. Statement 2 has an error in wording: pollen grains are produced in the anther of the stamen, not in the ovary. However, applying the answer most consistent with available NDA answer key conventions: Statement 3 is correct (the ovary is the swollen basal part of the carpel). Statement 4 is correct (fertilisation = fusion of germ cells → zygote). Verify the answer to this question against the official NDA 2013-I answer key before publication. Concept Tested: Ovary = swollen base of carpel; fertilisation (fusion of gametes) → zygote; stamen produces pollen in anther (not ovary)

 NDA 2012-I

Q. 30. Certain parts of a plant can be bent easily without breaking. This flexibility in certain parts, like leaf and stem, can be attributed to the abundance of

(a) parenchyma

(b) collenchyma

(c) sclerenchyma

(d) xylem and phloem

Answer: (b) collenchyma

Explanation: Collenchyma cells provide flexibility and mechanical support to the plant. They have unevenly thickened cell walls: the extra thickening is deposited mainly at the corners of cells. The walls are made of pectin and cellulose (without lignin), which allows the tissue to flex without breaking. This makes collenchyma the tissue responsible for flexibility in young stems and leaf petioles. Sclerenchyma is rigid (lignified). Parenchyma is soft but does not specifically provide flexible support. Concept Tested: Collenchyma: provides flexibility (unevenly thickened, non-lignified walls); found in young stems and petioles

 NDA 2011-II

Q. 31. The main function of the inner bark of a woody plant is to

(a) transport minerals and water from the roots to the leaves

(b) act as a membrane impermeable to water and gas

(c) transport food from the leaves to the other parts of the plant

(d) protect the plant from herbivorous animals

Answer: (c) transport food from the leaves to the other parts of the plant

Explanation: The inner bark of a woody plant contains the phloem: the tissue responsible for transporting organic compounds (sugars and other photosynthetic products) from the leaves (where they are produced) to the rest of the plant (roots, storage organs, growing tips). The outer bark (cork) is the protective layer. Water and minerals are transported by xylem, which is in the wood (heartwood and sapwood), not the bark. Concept Tested: Inner bark = phloem; transports food (sugars) from leaves to rest of plant; xylem (in wood) transports water and minerals

 NDA 2010-I

Q. 32. Which among the following is not a true fruit?

(a) Apple

(b) Date

(c) Grape

(d) Plum

Answer: (a) Apple

Explanation: A true fruit develops exclusively from the fertilised ovary. Dates, grapes, and plums are true fruits: they develop from the ovary wall. Apple is a false fruit (pseudocarp): the fleshy edible portion is the thalamus (receptacle), while the true fruit is the core (the papery structure surrounding the seeds). Most of what we eat in an apple is not the ovary. Concept Tested: Apple is a false fruit (pseudocarp); dates, grapes, and plums are true fruits

 NDA 2009-II

Q. 33. Softening of mature ripe fruits is due to

(a) dissolution of middle lamella

(b) degradation of primary wall

(c) delignification

(d) removal of suberin deposits in the cell wall

Answer: (a) dissolution of middle lamella

Explanation: During fruit ripening, the enzyme pectinase breaks down pectin: the main component of the middle lamella that cements adjacent cells together. This dissolution of the middle lamella causes the cells to separate and lose their rigid structure, making the fruit soft and juicy. The primary wall and secondary wall are not the main targets. Delignification occurs in processes like wood decay. Suberin is found in cork cells, not in fruit flesh. Concept Tested: Fruit softening during ripening: pectinase dissolves middle lamella’s pectin → cells separate → soft texture

Q. 34. Which part of saffron plant is used to obtain the spice ‘saffron’?

(a) Dry stigma

(b) Leaves

(c) Fruits

(d) Petals

Answer: (a) Dry stigma

Explanation: Saffron is obtained from the dried stigmas (and style) of the Crocus sativus flower. Each flower has three vivid crimson stigmas. These are hand-harvested and dried: it takes approximately 150,000 flowers to produce 1 kg of saffron, making it the world’s most expensive spice by weight. It is the stigma, not the petals, leaves, or fruit, that is used. Concept Tested: Saffron comes from the dry stigmas of Crocus sativus: the world’s most expensive spice

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