AP Inter 1st Year Botany Question Paper March 2018

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AP Inter 1st Year Botany Question Paper March 2018

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. Every answer may be limited to five 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 Sec-tion B’ and C.

Section – A (10 × 2 = 20)

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

Question 1.
Define the terms couplet and lead in taxonomic key.
Answer:
The contrasting characters occur in a pair is called Couplet. Each statement in the key is called lead.

Question 2.
Give the main criteria used for classification by Whittaker.
Answer:
The main criteria for classification proposed by Whittaker include cell structure, thallus organisation, mode of nutrition, reproduction and phylogenetic relationships.

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

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 sun in “Euphorbiaceae” family.

Question 5.
Differentiate between Apocarpous and Syncarpous overy.
Answer:
Apocarpous
A. Carpels are free
Ex : Rose

Synocarpous
A) Carpels are fused.
Ex : Tomato

Question 6.
What is omega taxonomy ?
Answer:
Taxonomy based on information from other branches i.e., Embryology, Cytology, Palynology, Phytochemistry, Serology etc., along with morphological characters is called omega taxonomy.

Question 7.
What is the feature of metacentric chromosomes ?
Answer:
The metacentric chromosome is ‘V’ shaped and the centromere is in the centre forming two equal arms.

Question 8.
Starch, cellulose, Glycogen and chitin are polysacharides found among the following. Choose the one appropriate and write against each.
(a) Cotton fibre
(b) Exoskeleton of cockroach
(c) Liver
(d) Peeled potato.
Answer:
a) Cotton fibre : Cellulose
b) Exoskeleton of cockroach : Chitin
c) Liver: Glycogen
d) Peeled potato : Starch.

Question 9.
In which phase of the cell cycle DNA synthesis occur ?
Answer:
Synthesis phase of Interphase.

Question 10.
Hydrophytes show reduced xylem. Why ?
Answer:
All submerged organs are capable of absorbing water. So hydrophytes show reduced xylem.

Section – B (6 × 4 = 24)

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

Question 11.
Give the salient features and importance of chryophytes.
Answer:

1. Chrysophytes includes Diatoms and Golden algae.
2. They are found in fresh water as well as in marine water.
3. Most of them are photosynthetic.
4. In Diatoms, the cell walls form two thin overlapping shells, epitheca over hypotheca which fit together as soap box.
5. The walls are embedded with silica and thus the walls are indestructible.
6. Diatoms leave large amount of cell wall deposits in their habitat, this accumulation is referred to as diatomaceous earth or ‘Kiesulghar’.
7. They reproduce asexually by binary fission and sexually by gametes.

Importance:

1. The diatomaceous soil is used in polishing, filtration of oils and syrups.
2. Diatoms are the chief producers in the ocean.

Question 12.
What is meant by homosporous and heterosporous pteridophytes ? Give two examples.
Answer:
The condition where only one type of spores are produced is called Homosporous pteridophytes.
Ex : Psilotum, Lycopodium

The condition where different types of spores are pro-duced is called Heterosporous pteridophytes.
Ex : Selagenella, Salvinia.

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

Question 14.
Describe the essential floral parts of plants belonging to Liliaceae.
Answer:
The essential floral parts of Liliaceae are Androecium and Gynoecium.

Androecium : Stamens are six, in two whorls of 3 each, free or Epiphyllous, anthers are dithecous, basifixed, introrse and dehisce longitudinally.

Gynoecium : Tricarpeilary, syncarpous, trilocular and superior ovary with many ovules on axile placentation. Style is terminal and stigma is capitate.

Question 15.
What are the characterestics of a prokaryotic cell ?
Answer:

1. Cell is surrounded by a cell wall, made up of polysaccharides, lipids and proteins.
2. Nuclear envelope is absent. Cell shows a single circular, supercoiled naked DNA called nucleoid.
   Nucleous is absent.
3. In addition to nucleoid, small DNA rings are present called plasmids.
4. Mitochondria, plastids, lysosomes, peroxisomes and cytoskeleton are absent. cyto
5. 70 s type of ribosomes are present.
6. Respiratory enzymes are located in cell membrane.

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 is periderm ? How does periderm formation take place in the Dicot stem ? .
Answer:
Phellogen, Phellem and Phelloderm together called periderm. In Dicots, stem continues to increase in girth due to activity of vascular cambium. As a result, the other cortical cells and epidermal layers ruptures and need to be replaced to provide new pulective layers. Hence another meinstematic lay er develops in the cortical region called cork cambium or phellogen. It is made up of narrow, thin walled cells which cuts of cells in both sides. The outer cells differentiates into work or phellem, while the Inner cells differentiates into secondary cortex or phellodym. The work in imperious to water due to subain deposition in the cell Nail. The secondary cortical cells are parenchymatous, Phellogen, Phellem and phellodlum are collectively known as puiderm.

Question 18.
Explain the morphological adaptations of hydrophytes.
Answer

1. Roots may be absent or poorly developed. In some plants . submerged leaves compensate for roots.
2. Root laps are usually absent. In some plants, Roots pockets are present.
3. Roots if present, are generally fibrous, adventitious, reduced in length unbranched or poorly branched.
4. Stem is long, slender flexible.
5. Leaves are thin, long and ribbon like or long and linear or finely dissected.
6. Floating leaves are large and flat with their upper surface coated with wax.

Section – C (2 × 8 = 16)

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

Question 19.
Explain different types of Racemose Inflorescences.
Answer:
Racemose inflorescences are of several types.
They are

1. Simple Raceme : The peduncle is simple, unbranched producing many pedicellate, bracteate flowers in acropetal manner, e.g. Crotalaria.
2. Coymb : The peduncles is long and beam many flowers in acropetal manner, but all the flowers are brought to the same level due to varied lengths of pedicels even though they are borne at different nodes, e.g. : Cassia, Cauliflower.
3. Umbel : The peduncle grow indefinitely and bears several bracteate and pedicellate flowers which have arisen from the same point. The inflorescence is covered by a whorl of bracts called involucre, e.g : Coriander, Carrot.
4. Spike : The peduncle is long and bears many sessile flowers arranged in acropetal manner, e.g : Achyranthus, Grass.
5. Spadix : The peduncle is long, fleshy and bears many unisexual flowers. Male flowers are the upper part, Female flowers are at the base of the peduncle with neuter flowers in between them. The inflorescence is covered and protected by an enlarged bract called spathe. e. g : Cocos, Colacasia.
6. Head : The peduncle is condensed and bears many unisexual and bisexual flowers arranged centripetally. e.g : Tridax, Sunflower.

Question 20.
Draw the diagram of a microsporangium and lable its wall layers. Write briefly about the wall layers.
Answer:

A typical angiospermics anther is bilobed with each lobe having two theca. The anther is a four sided structure consisting of four microsporangia located at the corners, two in each lobe.

In a transverse section, a typical microsporangium is cir-cular in out line and is surrounded by four wall layers, the (a) epidermis
(b) endothecium
(c) wall layers
(d) tapetum.

a) Epidermis : The epidermis is one celled thick, the cells present between the pollen sacs are th thin walled and their region is called as stomium which is useful for the dehiscence of pollen sacs.

b) Endothecium : It is present below the epidermis and expands radically with fibrous thickenings, at maturity these cells loose water and contract and help in the dehiscence of pollen sacs.

c) Wall layers : Beneath the Endothecium, there are thin walled cells, arranged in one to five layers, which also help in dehiscence of Anther.

d) Tapetum : The innermost wall layer is Tapetum, the cells are large, with thin cell walls, abundant cytoplasm and have more than one nuclei. Tapetum is a nutritive tissue which nourishes the developing pollen grains.

Question 21.
Describe the internal structure of 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 protoxylem is towards periphery and metaxylem is towards the center. Xylem is diarch to tetrarch condition.
Xylem helps in conduction of water and minerals and phloem helps in conduction of food materials.

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

d) Conjunctive, tissue: The parenchyma present between xylem and phloem is called conjunctive tissue which also involves in secondary growth.