AP Inter 1st Year Botany Question Paper May 2017

Successful navigation through AP Inter 1st Year Botany Model Papers and AP Inter 1st Year Botany Question Paper May 2017 builds students’ confidence in their exam-taking abilities.

AP Inter 1st Year Botany Question Paper May 2017

Time: 3 Hours
Maximum Marks: 60

General Instructions:
Note : Read the following instructions carefully.

1. Answer all 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. Each 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 Sections ‘B’ and ‘C’.

Section – A (10 × 2 = 20)

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

Question 1.
What is meant by manuals and monographs ?
Answer:
Manuals are useful in providing information for identification of names of species found in an area or Manual is a small book specially designed for ready reference.
Monographs contain information on any one taxon.

Question 2.
How are viroids different from viruses ?
Answer:
A virus containing nucleic acid and protein coat.
A viroid contain nucleic acid but lacked the protein coat.

Question 3.
What is paleobotany ? What is its use ?
Answer:
Study of fossil plants is called palaeobotany. It helps in understanding the course of evolution in plants.

Question 4.
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 (ground nut).

Question 5.
What is meant by parthenocarpic fruit ? How is it useful ?
Answer:
The formation of fruits without fertilization is called parthenocarpic fruit. Seedless fruits are produced commercially.

Question 6.
What is the significance of vacuole in a plant cell ?
Answer:
Vacuoles play an important role in osmoregulation.

Question 7.
An anther has 1200 pollen grains. How many pollen mother cells must have been there to produce them ?
Answer:
300 pollen mother cells.

Question 8.
What constituents of DNA are linked by glycosidic bond ?
Answer:
Nitrogen base and sugar molecule of DNA or the individual monosaeharides of a polysaccharide are linked by glycosidic bond.

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

Question 10.
What is meant by epipetalous condition ? Give an example.
Answer:
When stamens are attached to the pertals, this phenomenon is known as epipetalous condition. Ex : Datura / Solanum.

Section – B (6 × 4 = 24)

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

Question 11.
What are the characteristic features of Euglenoids ?
Answer:

1. Majority of the Euglenoids are fresh water organisms found in stagnant water.
2. They have a protein rich layer called pellicle which makes the body flexible.
3. They have two flagella, one is short and other one is long.
4. The anterior part of the cell bears an invagination consisting of cytostome (cell mouth), cytopharynx (gullet) and reservoir.
5. It consists of a photosensitive stigma of eyespot on the membrane of the reservoir.
6. The reproduction is by longitudinal binary fission. Ex : Euglena.

Question 12.
Differentiate between liverworts and mosses.
Answer:

Liverworts	Mosses
1. The plant body is thalloid, prostrate, dorsiventral.	1. The matured stage of Gametophyte is Erect, bearing spirally arranged leaves.
2. Vegetative reproduction takes place by fragmentation or gemmae.	2. Vegetative reproduction takes place by Fragmentation or gemmae buds formed (or) secondary protonema.
3. Sex organs are formed on same or on different.	3. Sex organs are formed on leafy Gametophores.
4. Paraphyses are absent.	4. Paraphyses are intermixed with sex Organs.
5. Elaters helps in dispersal of spores.	5. Peristomial teeth helps in dispersal of spores.
6. Spores germinate and develop into free living Gametophyte. Ex: Marchantia.	6. Spores germinate and develop into chlorophyllous protonema. Ex: Funaria.

Question 13.
“Vegetative reproduction is also a type of asexual reproduction “. Justify the statement
Answer:

1. In multicellular or colonial form of algae, moulds and mushrooms the body may split / break or get separated. Thus each fragment develops into matured individual.
2. In Bryophytes some plants have specialized structures for reproduction via fragmentation. Ex: Gemmae cups in liverworts.
3. In flowering plants the units of vegetative propagation such as runner, bulb, bulbil, reproductive leaves are capable of giving rise to new offsprings. These are called vegetative propagules.
4. Since the formation of these structures does not involve two parents. Hence, the vegetative reproduction is also considered as asexual reproduction.

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

1. Many plants belonging to this family are good source of proteins, (Red gram, Black gram).
2. Edible oils are obtained from soyabean, ground nut.
3. Pods of bean, soyabean are used as vegetables.
4. Seeds of garden pea and groundnut are edible.
5. Leaves of menthe are used as leafy vegetable.
6. Timber is obtained from Red sanders, Indian Rosewood.
7. Fibre is obtained from sunhemp.
8. Blue dye is obtained from Indigofera.
9. Yellow dye is obtained from Butea monosperma.
10. Derris indica is used as medicine.

Question 15.
What are nucleosomes ? What are they made up of ?
Answer:

1. Under Electron microscope chromatin appears as beads-on-string. The beads are known as Nucleosomes.
2. Atypical Nucleosome contains 200 bp of DNA double helix wrapped around a core of histone octomer.
3. A core of histone octomer having two copies each of four types of histone proteins viz H2A, H2B, H3 and H4.
4. H1 histone molecule lies outside the nucleosome core and seals the two turns of DNA by binding at a point where DNA enters and leaves the core.
5. The DNA that continues between two successive nucleosomes is called linker DNA.

Question 16.
What is the difference between lenticels and stomata ?
Answer:

Lenticels	Stomata
1. The lens shaped openings in the bark of Woody stems are called lenticels.	1. The minute openings occur in the epidermis of leaves and young stems are called stomata.
2. It is surrounded by loose parenchymatous Tissue. Lenticels does not have guard cells.	2. The stomata is surrounded by two bean shaped or Dumbbell shaped guard cells.
3. They do not perform the function of photosynthesis.	3. Chloroplasts present in guard cells perform the function of photosynthesis.
4. They help in exchange of gases.	4. They regulate transpiration and exchange of gases.

Question 17.
Though redundantly described as a resting phase, interphase does not really involve the 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 double.
c. G₂ phase : Proteinsynthesis continues. Cell organelles increases in number.

Question 18.
Write a brief account on the classification of xerophytes.
Answer:
Xerophytes are classified into three types.
They are :
a) Ephemerals: These are annuals which complete their life cycle within a short period..
Ex: Tribulus.

b) Succulents: They absorb large quantities of water during rainy season and store it in different plant parts in the form of mucilage. As a result the plant parts become fleshy or succulent. The store water is used during dry periods. Ex : Stem succulents : Opuntia. Root succulents : Asparagus. Leaf succulents : Aloe.

c) Non succulents: These are perennial plants can withstand prolonged period of drought. Ex : Gasuarina.

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.
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 polamuclei.

Question 21.

Describe the internal structure of a monocot root.
Answer:
The internal structure of Monocot root shows 3 zones.
They are :
1) Epidermis
2) Cortex and
3) Stele.

1) Epidermis : It is the outermost layer formed by thin walled, rectangular cells, which are compactly arranged without intercellular spaces. Cuticle and stomata are absent. Some epidermal cells (trichoblasts) produce tubular extensions called root hairs. They absorb capillary water from the soiL The epidermis of root is also known as rhizodermis or epiblema or piliferous layer.

2) Cortex : It is a wide and extensive tissue present between the epidermis and stele. It is bigger than the stele. It can be divided into three sub-zones.
They are :
a) Exodermis
b) General cortex and
c) Endodermis.

a) Exodermis: It is the outer part of the cortex and composed of one to two rows of thick walled, dead, suberised calls. In mature roots, when the outer epidermis is removed, the exodermis acts as a protective layer. It helps in preventing the exit of water from the root tissues.

b) General Cortex : It is formed below the exodermis layer. It is composed of several rows of thin walled living cells that are arranged loosely showing intercellular spaces. The cells of cortex help in the storage of food materials and lateral conduction of water from the epidermis to the stele.

c) Endodermis : The innermost layer of cortex and is composed of single layer of barrel shaped cells that are arranged compactly without intercellular spaces. The radical and transverse walls are wrapped by ligno-suberised bands called casparian bands. Some cells situated opposite to the protoxylem cells are thin walled and without casparian bands. These are known as passage cells which help in the entry of water from the cortex into the stele.

3) Stele: The central conducting cylinder. It is very prominent and bigger in size. The stele shows Pericycle, Vascular bundles and Medulla.
i) Pericycle : The layer of cells found beneath the endodermis is known as pericycle. The cells are thin walled, parenchymatous, rectangular and compact without intercellular spaces. The cells are meristematic and divide actively producing lateral roots. In old and mature roots, the pericycle is sclerenchymatous and gives mechanical strength.

ii) Vascular bundles : Bundles of xylem and phloem are found separately on different radii, one alternating with the other, at the peripheral boundary of the stele. These are known as radial’ or separate vascular bundles. The xylem is exarch and polyarch. More than six xylem bundles.

The ground tissue formed between the xylem and phloem stands is known as ‘conjunctive tissue’. It is usually parenchymatous. It helps in storage of food materials and provides mechanical strength.

iii) Medulla or Pith : The wide central part of the stele is called medulla or pith. It is made up of thin walled parenchyma which primary helps in the storage of food. In some monocot roots, the medulla is composed of thick walled lignified dead cells and helps in giving mechanical strength.