AP Inter 1st Year Botany Question Paper May 2019

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AP Inter 1st Year Botany Question Paper May 2019

Time: 3 Hours
Maximum Marks: 60

General Instructions:
Note : Read the following instructions carefully.

1. Answer ALL the questions of Section A. Answer any SIX questions out of eight in Section B and answer any TWO questions out of three in Section – C.
2. In Section A, questions from Sr. Nos. 1 to 10 are of ‘Very Short Answer Type’. Each question carries TWO marks. Every answer may be limited to 5 lines. Answer all the questions at one place in the same order.
3. In Section B, questions from Sr. Nos. 11 to 18 are of ‘Short Answer Type’. Each question carries FOUR marks. Every answer may be limited to 20 lines.
4. In Section C, questions from Sr. Nos. 19 to 21 are of ‘Long Answer Type’. Each question carries eight marks. Every answer may be limited to 60 lines.
5. Draw labelled diagrams, wherever necessary for questions in Section B and C.

Section – A (10 × 2 = 20)

Note : Answer all questions. Each answer may be limited to 5 lines.

Question 1.
What does ICBN stand for ?
Answer:
ICBN stands for International code for Botanical Nomenclature.

Question 2.
What do the terms ‘algal bloom’ and ‘red tides’ signify.
Answer:
In Cyanobacterium, the colonies and Trichomes or filaments are generally surrounded by gelatinous sheath. They often forms blooms in polluted water bodies.

Red tides : Dinoflagellates like Gonyaulax undergo rapid multiplications arid make the sea appear red.

Question 3.
Which group of plants is called vascular cryptograms ? Name the branch of Botany which deals with them.
Answer:
Pteridophytes are called vascular cryptogams. The branch which deals with pteridophytes is called pteridology.

Question 4.
What is meant by Parthenocarpic fruit ? How is it useful ? ‘
Answer:
The fruit which is formed without fertilization of the ovary is called parthenocarpic fruit. They are useful in commercial production of seedless fruits and also useful in juice industries.

Question 5.
What is meant by Epipetalous condition ? Give an example.
Answer:
The stamens are attached to the petals is called epipetalous . condition. E.g. : Datura, Brinjal, Tomato.

Question 6.
What is Geocarpy ? Name the plant which exhibits this phenomenon.
Answer:
The development of fruit inside the soil is called Geocarpy.
E.g. : Arachis hypogeal (Groundnut).

Question 7.
What is the function of a Polysome ?
Answer:
The ribosomes of a polysome translate the mRNA into proteins.

Question 8.
Give one example for each of amino acids, sugars, nucleotides and fatty acids.
Answer:
Amino acids : Glycine, alanine.
Sugars : Glucose, ribose
Nucleotides : Adenylic acid.
Fatty acid : Palmitic acid / Arachidonic acid.

Question 9.
Which of the phases of cell cycle is of longest duration ? ,
Answer:
Interphase.

Question 10.
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 populations belonging to different species occurring in an area is called community.

Section – B (6 × 4 = 24)

Note : Answer any six questions. Each answer may be limited to 20 lines.

Question 11.
Give a brief account of Dinoflagellates.
Answer:
a) Dinoflagellates are mostly marine and photosynthetic. They appear yellow, green, brown, blue or red depending on the pigment in their cells.
b) The cell wall has stiff cellulose plates on the outer surface.
c) They have two flagella and produce spinning movements. So these protists Eire Edso called “Whirling whips”.
d) The nucleus has condensed chromosomes which are without histones, called mesokaryon.
e) Some dinoflagellates like Noctiluca show bioluminescence.
f) Red dinoflagellates like Gonyaulax undergo rapid multiplication and make the sea appear red (Red tides in Mediterranean sea).
g) Toxins produced by them may kill fishes.

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 madeup of cellulose, pectin and polysulphate esters.	3. Cell wall is madeup 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.
Distinguish between asexual and sexual reproduction. Why is vegetative reproduction also considered as a type of asexual reproduction ?
Answer:

Asexual	Sexual
1. Single parent is involved.	1. Two parents are involved
2. Offsprings are genetically identical to each other and to their parent.	2. Offsprings are not identical to parents.
3. No fertilization occurs.	3. Fertilization occurs.
4. No gametes are involved.	4. Gametes are involved.
5. No mixing of hereditary material.	5. Mixing of hereditary material.

Question 14.
Give economic importance of plants belonging to Fabaceae.
Answer:

1. Pulses like red gram (Cajanus), black gram (Phaseolus) green gram (Phaseolus aureus), Bengal gram (Cicer arietinum) are rich source of proteins.
2. Pods of Dolichos and Glycine are used as vegetables.
3. Seeds of Pisum and Araehis are edible.
4. Ground nut oil from Araehis seeds and soyabean oil from Glycine max are used in cooking.
5. The oil cake from Araehis is used as fodder.
6. The oil from the seeds of Derris indica is used in making medicines.
7. The seeds of Abrus precatorius are used as Goldsmith’s weight.
8. Seeds of Trigonella are used as condiment and medicine. The leaves are used as vegetable.
9. Sesbania and Tephrosia are used as green manure.
10. Crotalaria and Phaseolus are used as fodder.
11. Fibre from Crotalaria is used in making ropes.
12. Indigofera yields blue dye, which is used in colouring clothes.
13. Wood from pterocarpus is used in making musical instruments.

Question 15.
What are nucleosomes ? What are they made of ?
Answer:
Under electron microscope, chromatin appears as “beads on string”. These seeds are known as nucleosomes. A typical nucleosome consists of 200 base pairs of DNA wrapped around a core of histone octamer having two copies of each of four types of histone proteins. They are H₂ A, H₂ B, H₃ and H₄. H₁ Histone lies outside the nucleosome core and seals the two turns of DNA by binding at the point when DNA enters and leaves the core. The DNA continues between two. nucleosomes is called linker DNA. This chromatin gradually condense into chromosomes.

Question 16.
Though redundantly described as a resting phase, interphase. . does not really 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 is the difference between Lenticels and Stomata ?
Answer:

Lenticels	Stomata
1. Lens shaped openings in the cork of woody stems.	1. Openings present in the epidermis of the leaf.
2. They contain closely arranged parenchymatous cells.	2. Stomata is surrounded by specialised Guard cells.
3. They permit the exchange of gases between the outer atmosphere and the inner tissues of the woody organs.	3. They perform transpiration and exchange of gases.
4. They are always open.	4. Opening and closing mecha-nism is present.

Question 18.
Enumerate the morphological adaptations of hydrophytes.
Answer:

1. Roots may be absent or poorly developed. In some plants, submerged leaves compensate for roots.
2. Root caps are usually absent. However in some amphibious plants which grow in mud, roots are well developed with distinct root caps. In some plants root caps are replaced by root pouckets.
3. Roots, if present are generally fibrous, adventitious, reduced in length, unbranched or poorly branched.
4. Stem is long, slender and flexible.
5. Leaves are thin and either long and ribbon shaped as long and linear or finely dissected. Floating leaves are large and flat with their upper surfaces coated with wax.

Section – C (2 × 8 = 16)

Note : Answer any two questions. Each answer may be limited to 60 lines.

Question 19.
Explain how stem is modified variously to perform different functions.
Answer:
Stems are modified in several ways to perform different functions.
They are :
1) Tendrils : Slender, spirally coiled structures which may develop either from auxiliary bud (cucumber) or from terminal bud (grapes) are called tendrils. They help in climbing.

2) Thorns : Buds are modified into woody, straight pointed thorns which protect plants from grazing animals.
Ex : Citrus, Bougain villaea.

3) Phylloclade : In some plants of acid zones, leaves are modified into scales or spines to reduce the rate of transpiration. In such plants, stems are modified into flattened, green structure which carryout photosynthesis. Such stems are called phylloclades. Ex : In euphorbia stem is cylindrical, in casuarina needle like, and in opuntia – flattened, fleshy green.

4) Bulbils : In some plants, the vegetative buds or floral buds store food materials. At maturity, may detach from the parent plants, develop adventitious roots, grow as new plants thus help in vegetative reproduction. Ex : Diascoria.

5) Underground stems : In some plants, stem grows into soil, store food materials, show perennation, to resist unfavourable conditions and also help in vegetative reproduction. Such stems are called underground stems.
Ex : Rhizome – Ginger, com – colacacia.

6) Sub aerial stems : In some plants, some part of the stem is underground and some part is aerial. Such stems are called sub aerial stems. In such plants, slender, lateral branches arises from the base of the main axis, grow vertically, arches downwards, produce adventitious roots when touches the ground. When they separates from the parent plant, they develop into new plants they help in vegetative reproduction.
Ex : Stolons – Nerium, Jasmine
Suckers – Chrysanthemum, Mertha.

Question 20.
With a neat, labelled diagram, describe the parts of a mature angiosperm embryo sac. Mention the role of synergids.
Answer:
Mature angiosperm embryosac shows three parts.
They are :
1) Egg apparatus
2) Antipodals
3) Central cell.

1) Egg Apparatus : Three cells present towards the micropyle of the embryosac together called egg apparatus. Of which, the central, largest one is called egg and two lateral cells are called synergids. Synergids show finger like projections towards the micropyle called filliform apparatus.

2) Antipodals : Three cells present towards the chalazal end of the ovule are called antipodals. They are also referred to as vegetative cells of the embryosac and disintegrates before or after fertilisation.

3) Central cell : It is the largest cell of the embryosac. It is formed by the fusion of two polar nuclei. It is also called secondary nucleus. It shows central vacuole and 2 haploid polarnuclei.

Role of synergids :

1. The filliform apparatus of the synergids absorbs food materials from the Nu cells and supplies to embryosac.
2. It also secretes some chemicals which direct the growth of the pollen tube towards embryosac.

Question 21.
Describe the internal structure of a Dicot Root.
Answer:
A thin transverse section of dicot root shows three parts namely :
i) Epidermis
ii) Cortex and
iii) Stele.

i) Epidermis : It is the outer most layers made of thin walled cells. Some cells protrude in the form of unicellular root hairs. So called Epiblema. It protects the inner parts. Root hairs help in absorption of water from the soil.

ii) Cortex : It consists of several layers of thin walled parenchyma cells with inter cellular spaces. The Innermost layer of cortex is called Endodermis. It comprises a single layer of barrel shaped cells without Intercellular spaces. The tangential as well as the radial walls of Endoderm cells show suberin thickenings called casparian strips. Some cells opposite to protoxylem lack these strips called passage cells. They help in the movement of water and dissolved salts from
cortex into xylem.

iii) Stele : It is the central part, consists of 4 layers.
a) Pericycle : It is single layered, made of thin walled parenchyma cells, present next to endodermis. It produces lateral roots” and become vascular cambium during secondary growth.

b) Vascular Bundle : Xylem and phloem constitutes vascular Bundle. They are arranged on different radius (in alternate manner) so called Radial vascular Bundle, Xylem is exarch, where protoxyler is towards periphery and metaxylem is towards the center. Xylem diarch to tetrarch condition. Xylem helps in conduction of water a minerals and phloem helps in conduction of food materials.

c) Medulla : It is absent or small, made of parenchyma When present, it helps in the storage of food and water.

d) Conjunctive tissue : The parenchyma present betw xylem and phloem is called conjunctive tissue which also involve secondary growth.