Case study (4 Marks)

Question 14 Marks

Each flower normally has four floral whorls, viz., calyx, corolla, androecium and gynoecium. The calyx is the outermost whorl of the flower and the members are called sepals. Corolla is composed of petals. Petals are usually brightly coloured to attract insects for pollination. The mode of arrangement of sepals or petals in floral bud with respect to the other members of the same whorl is known as aestivation. The main types of aestivation are valvate, twisted, imbricate. The shape and colour of corolla vary greatly in plants. Corolla may be tubular, bell- shaped, funnel-shaped or wheel-shaped and vexillary.

i. Observe the given figure mentioned A, B, C and D. Also mention its function. Identify D and mention its
example. (1)
ii. Ganosepalous, Ganopetalous, Polysepalous, Polypetalous, Imbricate. (1)
iii. What is Valvate and twisted aestivation? (2)

OR

Which of the following shows imbricate? Explain imbricate aestivation? (2)

Answer

i. A-androecium, B-gynoecium, C-corolla, D-calyx
Androecium: It contains pollen grains, which are responsible for reproduction in the male part of the plant.
Gynoecium: It holds ovary, which is transformed into fruit after fertilization. Corolla: The corolla promotes pollination and protects the reproductive organs. Calyx: The main function of the calyx is to protect the floral shoot during the bud stage.
ii. • Ganosepalous: Plants with many fused sepals are known as Gamosepalous. Eg, Hibiscus, Periwinkle, etc.
• Polypetalous: Polysepalous plants are also categorized based on sepals. Eg, Rose, Southern magnolia, etc.
iii. • When the margins of the petals are in contact with each other without overlapping, it is called valvate aestivation. For example, Calotropis.
• Contoured or twisted estivation occurs when the margin of one petal overlaps the margin of the next. Example - Hibiscus.

OR

Figure (c), Imbricate aestivation occurs when the margins of sepals or petals overlap without a clear direction. There is an irregular overlapping of petals by each other in this type of aestivation.

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Question 24 Marks

The fungi constitute a unique kingdom of heterotrophic organisms. They show a great diversity in morphology
and habitat. Fungi are cosmopolitan and occur in air, water, soil, and on animals and plants. They prefer to grow in warm and humid places. Most fungi are heterotrophic and absorb soluble organic matter from dead substrates and hence are called saprophytes. When a fungus reproduces sexually, two haploid hyphae of compatible mating types come together and fuse. In some fungi, the fusion of two haploid cells immediately results in diploid cells (2n). The fungiform fruiting bodies in which reduction division occurs, leading to the formation of haploid spores. Symbionts - in association with algae as lichens and with roots of higher plants as mycorrhiza. Three types of reproduction occur in fungi

i. Observe the given flow chart of reproduction and mention which steps involves in the sexual cycle of fungi.
(1)
ii. What is Rhizopus? Also, mention Rhizopus - wheat rush a correct match? (1)
iii. What is Mycorrhiza? And mention its function. (2)

OR

In which form Fungi Stores Food Material? Do fungi have food vacuoles? (2)

Answer

1. The sexual cycle of fungi involves the following steps:
a. The fusion of protoplasms between two motile or non-motile gametes is called plasmogamy.
b. The fusion of two nuclei is called karyogamy.
c. Meiosis in zygote results in haploid spores.
ii. Rhizopus is a fungus that reproduces by spore formation. No, Rhizopus - wheat rush is not a correct match.
iii. • Mutualistic associations between fungi and plant roots are called mycorrhizae.
• Fungi that form mycorrhizal (mycorrhizal fungi) can deliver inorganic nutrients such as phosphate.
• In exchange, the plants supply the fungi with organic nutrients.

OR

Fungi store food in the form of glycogen, along with oil bodies.
Plants, protists, mammals, and fungi all have vacuoles in their cells. Food vacuoles are sacs enclosed by a membrane and have a digestive function.

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BIOLOGY Case study (4 Marks)

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