TS Inter 1st Year Botany Question Paper March 2017

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TS Inter 1st Year Botany Question Paper March 2017

Time: 3 Hours
Maximum Marks: 60

Section – A (10 × 2 = 20)

Answer All questions

Question 1.
Give the scientific name of Mango. Identify the generic name and specific epithet.
Answer:
Mangifera Indica. Generic name is ‘Mangifera’ and Specific epithet is ‘indica’.

Question 2.
Why is Mendel considered as the Father of Genetics ?
Answer:
Mendel conducted Hybridization experiments on Pea plants and also proposed Laws of inheritance. So Mendel is considered as Father of Genetics.

Question 3.
What is palaeobotany ? What is its use ?
Answer:
It deals with the study of Fossil plants. It helps in understanding the course of evolution in plants.

Question 4.
What is the morphology of cup like structure in Cyathium ? In which family it is found ?
Answer:
In Cyathium, Cup like structure is formed from involucre of Bracts. It is seen in “Euphorbiaceae” Family.

Question 5.
Define venation. How do dicots differ from monocots with respect to venation ?
Answer:
The arrangement of Veins and Veinlets in the lamina of the leaf is called venation. In Dicots, Reticulate venation is seen (Net like arrangement of Veins) where as in Monocots Parallel venation is seen (parallel arrangement of veins).

Question 6.
What is geocarpy ? Name the plant which exhibits this phenomenon.
Answer:
The development of fruit inside the soil is called Geocarpy. It is seen in Arachis hypogea.

Question 7.
What does ‘s’ refer in a 70s and 80s ribosome ?
Answer:
In both 70s and 80s ribosomes, ‘s’ stands for the sedimentation coefficient expressed in Svedberg units.

Question 8.
An anther has 1200 pollen grains. How many pollen mother cells must have been there to produce them ?
Answer:
300 pollen mother cells.

Question 9.
Define population and community.
Answer:
A group of similar individuals belonging to same species found in an area is called population. An assemblage of all the populations belonging to different species occurring in an area is called community.

Question 10.
What is the difference between a nucleoside and nucleotide ?
Answer:
Nitrogen base and a sugar molecule is called nucleoside. Nitrogen base, as sugar molecule and phosphate group is called nucleotide.

Section – B (6 × 4 = 24)

Answer any Six Questions.

Question 11.
Give the salient features and importance of chrysopytes.
Answer:
a) Chrysophytes includes Diatoms and Golden algae.
b) They are found in fresh water as well as in marine water.
c) Most of them are photosynthetic.
d) In Diatoms, the cell walls form two thin overlapping shells, epitheca over hypotheca which fit together as soap box.
e) The walls are embedded with silica and thus the walls are indestructible.
f) Diatoms leave large amount of cell wall deposits in their habitat, this accumulation is referred to as diatomaceous earth or ‘Kiesulghar’.
g) They reproduce asexually by binary fission and sexually by gametes.

Importance:
a) The diatomaceous soil is used in polishing, filtration of oils and syrups.
b) Diatoms are the chief producers in the ocean.

Question 12.
Differentiate between red algae and brown algae.
Answer:

red algae	Brown algae
1) They belong to class Rhodophyceae.	1) They belong to class Phaeophyceae.
2) Most of them are marine and some are fresh water forms.	2) They live in fresh water, brackish and salt water.
3) Cell wall is made up of cellulose, pectin and polysulphate esters.	3) Cell wall is made up of Cellulose and algin.
4) The thallus is multicellular.	4) The thallus range from simple branched filamentous forms to profusely branched forms.
5) Flagella are absent.	5) Flagella are 2, unequal and lateral.
6) The major pigments are Chlorophyll-a, d, and r-phycoerythrin.	6) The major pigments are Chlorophyll-a, c, carotenoids and fucoxanthin.
7) Food materials are stored in the form of Floridian starch.	7) Food materials are stored in the form of mannitol and laminarin.
8) Asexual reproduction occurs by non motile spores.	8) Asexual reproduction occurs by biflagellate zoospores.
9) Sexual reproduction is by non-motile gametes.	9) Sexual reproduction is by motile gametes.
10) E.g : Polysiphonia, Porphyra.	10) E.g: Ectocarpus, laminaria.

Question 13.
Identify each part in a flowering plant and write whether it is haploid (n) or diploid (2n) :
a) Ovary
b) Anther
c) Egg
d) Pollen
e) Male gamete
f) Zygote
g) Antipodal
h) Megaspore mother cell
Answer:
a) Ovary : Diploid (2n)
b) Anther : Diploid (2n)
c) Egg : Haploid (n)
d) Pollen : Haploid (n)
e) Male gamete : Haploid (n)
f) Zygote : Diploid (2n)
g) Antipodal : Haploid (n)
h) Megaspore mother cell : Diploid (2n)

Question 14.
Write a brief account on the class of Dicotyledonae of Bentham and Hooker’s classification.
Answer:
In Bentham and Hooker’s system of classification, the class Dicotyledonae was divided into three sub-classes namely Polypetalae, Gamopetalae and Monochlamydae. Polypetalae, subclass is again divided into three series namely Thalamiflorae (6 orders), Disciflorae (4 orders) and Calyciflorae (5 orders). Gamopetalae, sub class is again divided into three series namely Inferae (3 orders), Heteromerae (3 orders) and Bicarpellatae (4 orders). Monochlamydae, sub class was divided into 8 series.

Question 15.
Describe the structure and functions of power houses of cell.
Answer:
Mitochondria is referred to as power houses of the cell. It is a rod shaped cell organelle having a diameter of 0.2 to 1.0 millimicrons and a length of 1.0 to 4 millimicrons. They are the sites of Aerobic respiration and produce energy in the form of ATP hence they are called power houses of the cell.

Each mitochondrion is a double membrane bound cell organelle which leaves a perimitochondrial space in between them. The outer membrane is smooth and the inner membrane forms a number of infoldings towards inside called cristae. Inner to inner membrane, there is a fluid filled space called matrix. It possesses a single circular DNA molecule, few RNA molecules, 70s ribosomes and the components required for the synthesis of proteins. The cristae possess stalked particles named F₁ particles or oxysomes. These are the sites of Aerobic respiration and produce energy in the form of ATP.

Question 16.
Though redundantly described as a resting phase, interphase does not involve rest. Comment.
Answer:
The interphase also called phase of non apparent division though called the resting phase. It is the time during which the cell is preparing for division by undergoing cell growth and DNA replication. The interphase is divided into three further phases. They are a.G₁ phase, S-phase and G₂ phase.

a. G₁ phase : It corresponds to the interval between mitosis and initiation of DNA replication. In this, the cell is metabolically active and grows continuously.
b. S-phase: DNA replication takes place. The amount of DNA per cell doubles.
c. G₂ phase : Proteinsynthesis continues. Cell organelles increases in number.

Question 17.
What are the differences between Lenticels and Stomata ?
Answer:

Lenticels	Stomata
a) Lens shaped openings in the cork of woody trees are called lenticels.	a) Pores present in the epidermis of young stems and leaves.
b) They show closely arranged parenchymatous cells. Guard cells are absent	b) Stomata is covered by a bean shaped guard cells.
c) Lenticels do not involve in photosynthesis.	c) Guard cells contain chloroplasts and involve in photosynthesis.
d) They allow gaseous exchange through the compactly arranged cork cells of the bark.	d) Stomata regulate the process of transpiration and gaseous exchange.

Question 18.
Give in detail the anatomical adaptations shown by Xerophytes.
Answer:
a) Epidermis is covered with thick cuticle to reduce the rate of transpiration.
b) Epidermal cells may have silica crystals.
c) Epidermis may be multilayered as in leaves of Nerium.
d) Stomata are generally confined to lower epidermis of leaves called hypostomatous. They are present in pits called sunken stomata.
e) Mechanical tissues are very well developed.
f) Vascular tissues are very well developed.

Section – C (2 × 8 = 16)

Answer any two Questions.

Question 19.
Define root modification. Explain (with diagrams) how root is modified to perform different functions.
Answer:
A change in the normal structure of root to carry out new functions according to environment is called root modification.

Root modifications: In some plants, roots change their shape and structure to perform functions other than absorption and conduction of water and Minerals called root modifications.
They are of different types.

1. In Carrot, turnip (Tap roots), Sweat potato (Adventi-tious roots), Asparagus (Fibrous roots) become swollen due to storage of food called storage roots.
2. In Banyan tree, Roots arise from the branches grow into the soil, become pillar like and give additional support called prop roots or pillar roots.
3. In Maize, sugarcane, roots arise from the lower nodes of the stem, give additional support called stilt roots.
4. In Mangroves like Rhizophora and Avicennia, Many roots come out of the ground and grow vertically upwards, help in respiration called Pneumatophores.
5. In Epiphytes like Vanda, special adventitious roots arise, help in absorption of moisture from almosphere called Velamen roots.
6. In partial parasites like viscum and strga, some Haustorial roots enter into xylem of the host plant to get water and Minerals. In complete parasitic like cuscuta and Rafflesia, the haustorial roots enter into xylem and phloem of the host plant and obtain water and Minerals and food materials called Parasitic roots.
7. In the members of Fabaceae, the roots are inhabited by Rhizobium bacteria which helps in N₂ fixation called Nodular roots.
8. In some plants like Taeniophyllum, the roots are chloro – phyllous and perform photosynthesis so called photosynthetic roots.

Question 20.
Write a brief account on agents of pollination.
Answer:
Plants use two abiotic and one biotic agents to achieve pollination.
Abiotic agents : Wind and water are the abiotic agents.
A) Anemophily : Pollination by wind is called anemophily. Wind pollinated plants show well exposed stamens, produce light pollen grains and feathery stigma to trap pollen.

B) Hydrophily : Pollination by water called hydrophily. In Vallisneria-pollination occurs on the surface of water called Epihydro- phily. In Zoostera-pollination occurs under water called Hypohydrophily.

Biotic agents : Animals are the biotic agents help in pollination. Pollination by animals is called Zoophily. It is various types.
a) Entomophily: Pollination by insects is called Entomophily. Insect pollinated plants are large, colorful, fragrant and rich in nectar.
b) Omithophily: Pollination by birds is called Omithophily.
c) Chiropterophily: Pollination by bats is called Chiropterophily.
d) Therophily: Pollination by Squirrels is called Therophily.
e) Ophiophily: Pollination by snakes is called Ophiophily.

Question 21.
Describe the internal structure of dorsiventral leaf with the help of a diagram.
Answer:
Transverse section of a dorsiventral leaf (dicot leaf) shows 3 important parts.
They are :
1. Epidermis
2. Mesophyll and
3. Vascular bundles.

1) Epidermis : Epidermis is present on the both the upper surface (upper epidermis) (adaxial) and the lower surface (abaxial) of the leaf (Lower Epidermis). The epidermis is made up of one row of barrel shaped Achlorophyllous cells, which are arranged compactly without intercellular spaces. The cells are filled with vacuolated and nucleated protoplast. On outerside of the epidermis a waxy layer called Cuticle is present. Stomata are present, more on the lower surface than on the upper surface. Each stoma is surrounded by two kidney shaped guard cells. They are chlorophyllous and regulate the opening and closing of stomata. Epidermis shows multicellular uniseriate hairs. The cells of leaf hairs are filled with water. They protect the inner tissues by absorbing the heat and prevents evaporation of water from the leaf surface. The stomata help in the gaseous exchange and also promote transpiration.

2) Mesophyll : The ground tissue that extends between the upper and lower epidermal layers is called the mesophyll. It is composed of thin walled parenchyma with chloroplasts. It is chiefly concerned with the synthesis of carbohydrates. In dicot leaves mesophyll is differentiated into two parts namely,
i) Palisade parenchyma and
ii) Spongy parenchymea.

i) Palisade parenchyma: Part of the mesophyll found beneath the upper epidermis is called ‘palisade tissue’. It shows elongated, columnar cells arranged in 1 – 3 vertical rows. Narrow intercellular spaces are present between the cells. In these cells, large numbers of chloroplasts are found nearer to the cell wall. Palisade tissue is primarily concerned with the manufacture of carbohydrates in the presence of sunlight.

ii) Spongy parenchyma: Part of the mesophyll found towards the lower epidermis is called spongy tissue. It shows 3 – 5 rows of irregular shaped cells that are arranged loosely with large intercellular spaces. Some intercellular spaces present in the vicinity of the stomata are very large, forming air chambers (air cavities). In these cells, number of chloroplasts is less. That is why the upper surface of leaf is dark green and the lower surface is light green in colour. Spongy tissue has a primary role in gaseous exchange, apart from the synthesis of food materials.

3) Vascular bundles : Vascular bundles are extended in the mesophyll in the form of veins. They help in supplying water, mineral salts and food materials all over the leaf surface. Veins also provide mechanical strength to the leaf.

The vascular bundles are conjoint, collateral and closed. The xylem is present on the upper side and phloem is on the lower side. Cambium is absent between them. Xylem shows vessles, tracheids, parenchyma and fibres. Phloem shows sieve tubes companion cells and phloem parenchyma.

Each vascular bundle is surrounded by a layer of specialised – mesophyll cells that are arranged closely and compactly without intercellular spaces. This layer is called bundle sheath or border parenchyma. The bundle sheath cells divide and grow towards the upper and lower epidermal layers. These are calledbundle sheath extensions. They help in the conduction of food materials form the mesophyll to the vascular bundles.