TS Inter 2nd Year Botany Question Paper May 2018

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TS Inter 2nd Year Botany Question Paper May 2018

Time: 3 Hours
Max.Marks:60

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 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 comes with 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 x 2 = 20

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

Question 1.
Does transpiration occur at night? Give an example.
Answer:
Yes, Transpiration occur at night in succulent plants. In those plants, stomata open during the night and remain closed
during the daytime. Ex: Snyophyllum, Cacti.

Question 2.
What is the shape of TMV? What is its genetic material?
Answer:
The shape of T.M.V is road shape. Its genetic material is SSRNA. (Single Stranded RNA).

Question 3.
Define plasticity. Give an example.
Answer:
The ability of plants to follow different pathways in response to the environment or phases of life to form different kinds of structures is called plasticity. Ex: Heterophily.

Question 4.
In a typical DNA molecule, the proportion of Thymine is 30% of the N. bases. Find out the percentages of other N. bases.
Answer:
A =T, G ≡ C
30 = 30 20 ≡ 20
So Menine (A) = 30%,
Guanine (G) = 20%,
Cytosine (C) = 20%

Question 5.
What is point mutation? Give an example.
Answer:
Change of single base pair in the gene for beta globulin chain that results in the change of amino acid residue glutamate to valine. It results in a diseased condition called ‘sickle cell anemia’.

Question 6.
What are the components of a transcription unit?
Answer:

• A promoter
• The structural gene
• A terminator.

Question 7.
How can you differentiate between exonucleases and endonucleases?
Answer:

Exonucleases	Endonucleases
They remove nucleotides from the ends of the DNA.	They make cuts at specific locations within the DNA.

Question 8.
Which part of the plant is best suited for making virus-free plants and why?
Answer:
Apical meristems of plants are best suited for making virus-free plants. Because this region consists of actively growing meristematic tissue and can not infected by virus.

Question 9.
What are fermentors?
Answer:
Large vessels in which microbes are grown in large numbers on an individual scale are called fomenters.

Question 10.
What is Green Revolution? Who is regarded as father of green revolution?
Answer:
substantial and dramatic increase in agriculture production is called green revolution. Norman Borlaug is regarded as the Father of Green Revolution.

Section – B
6 x 4 = 24

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

Question 11.
How does ascent of sap occur in tall trees?
Answer:
Upward movement of water through xylem against gravitational force is called ascent of sap. The transpiration-driven ascent of xylem sap depends on –

• Cohesion – mutual attraction between water molecules.
• Adhesion – attraction of water molecules to polar surfaces.
• Transpiration pull – driving force for upward movement of water.

These properties give water high tensile strength and high capillarity. In plants, capillarity is aided by the small diameter of the tracheary elements. As water evaporates through the stomata, Since the thin film of water over the cells is continuous, it results in pulling of water, molecule by molecule into the leaf from the xylem. Also, because of lower concentration of water vapour in the atmosphere, water diffuses into the surrounding air. This create transpiration pull. The forces generated by the transpiration can create pressure sufficient to lift a xylem-sized column of water over 130 meters high.

Question 12.
Explain different types of cofactors.
Answer:
Cofactors are of two types. They are:
a) Metal ion co-factors: Metallic cations get tightly attached to the apoenzyme are called metalloenzymes.
Ex: Cu²⁺ cytochrome oxidase.
b) Organic co-factors: They are of two types.

1. Co-enzymes: They are the small organic molecules which are loosely associated with the Apoenzyme.
   Ex: Thiamine pyrophosphate – Vitamin B₁.
2. Prosthetic group: They are the organic co-factors which are tightly bound to the Apoenzyme. .
   Ex: Haeme is the prosthetic group of enzyme Peroxi dase.

Question 13.
Write a note on agricultural/horticultural applications of auxins.
Answer:

1. IBA, NAA, and IAA help to initiate rooting in stem cuttings, widely used for plant propagation in horticulture.
2. Auxins like 2, 4- D, 2, 4, 5- T act as herbicides and kills broad-leaved dicot weeds to prepare weed-free lawns.
3. Auxins stimuÌate fruit growth. Ex: Tomato.
4. Auxins induce flowering in pineapple.
5. Auxins prevent premature leaf and fruit drop.

Question 14.
How are bacteria classified on the basis of number and distribution of flagella?
Answer:
Bacteria are classified into four types based on the number and arrangement of flagella: They are

1. Monotrichous: A single polar flagellum is present at one end of the Bacterial cell.
2. Lophotrichous: A tuft of flagella at one pole of the cell.
3. Amplutrichous: A single flagellum at each end of the oil.
4. Peritrichous: Flagella distributed over the entire cell.

Question 15.
Tabulate any eight differences between C₃ and C₄ plants.
Answer:

C3 plants	C4 plants
1. Kranz’s anatomy is not shown by the Leaves.	1. Leaves show Kranz anatomy.
2. Chloroplast dimorphism is absent.	2. Chloroplast dimorphism is seen.
3. Only the Calvin cycle occurs.	3. C4 cycle occurs in mesophyll cells and the Calvin cycle occurs in bundle sheath cells.
4. The primary acceptor of CO2 is RUBP	4. The primary acceptor of CO2 is PEPA.
5. The first formed product is PGA (3C).	5. The first formed product is OAA(4C).
6. Less efficient in utilizing atmospheric CO2.	6. More efficient in utilizing atmospheric CO2.
7. Photo respiration is high.	7. Photo respiration is not detectable.
8. The optimum temperature for this pathway is 15°C to 25°C.	8. The optimum temperature for this pathway is 30°C to 45°C.
9. Photosynthetic yield is low.	9. Photosynthetic yield is more.

Question 16.
Draw the schematic/diagrammatic presentation of the lac operon.
Answer:

Question 17.
Differentiate between the following:
a) Dominant and Recessive.
b) Homozygous and Heterozygous.
Answer:
a)

Dominant	Recessive
A character is expressed phenotypically in both homozygotes and heterozygotes.	A character which is not expressed phenotypically in a Heterozygous condition

b)

Homozygous	Heterozygous
Two similar or identical alleles for a single character.	To different alleles for a single character.

Question 18.
List out the beneficial aspects of transgenic plants.
Answer:
Plants with desirable characteristics created through gene transfer methods are called transgenic plants.
Beneficial aspects:
A) Transgenic crop plants are efficient because they have many beneficial traits like virus résistance, insect resistance and herbicide resistance. Ex: Papaya is resistant to papaya ring spot virus. Bt cotton is resistant to insects.

B) Transgenic plants are resistant to bacterial and fungal pathogens.
Ex: Transgenic Tomato plants are resistant to Pseudomonas bacterium. Transgenic potato is resistant to Fungus Phytophthora.

C) Transgenic plants which are suitable for food processing are produced with improved nutritional quality.
Ex: Transgenic Tomato “Flavor Savr” are bruise resistant suitable for storage and transport due to delayed ripening and offers higher shelf life. Transgenic Golden Rice “Taipei’ is rich in Vitamin – A, and prevents blindness.

D) Transgenic plants are used for hybrid seed production. Ex: Male sterile plants of Brassica napus are produced. This will be eliminate the problem of manual emasculation and
reduces the cost of hybrid seed production.

E) Transgenic plants have been shown to express the genes of insulin, interferons, human growth hormones, antibiotics, and antibodies.

F) Transgenic plants are used as bioreactors for obtaining commercially useful products, specialized medicines, and antibodies on large scale is called molecular farming.

Section – C
2 × 8 = 16

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

Question 19.
Give an account of glycolysis. Where does it occur? What are the end products? Trace the fate of these products in both aerobic and anaerobic respiration.
Answer:
Glucose is broken down into 2 molecules of pyruvic acid is called Glycolysis. It was given by Gustav Embden, Mayerh of and Parnas’s so-called EMP Pathway. It occurs in the cytoplasm of the cell and take place in all living organisms. At the end of Glycolysis, 2 PA, 2 ATP, and 2 NADPH+ H⁺ are formed as End products. In Aerobic Respiration, Pyruvic acid,
NADPH + H⁺ are completely oxidised through TCA cycle, ETS and produce 36 ATP molecules. In Anaerobic respiration, pyruvic acid undergoes partial oxidation and releases CO₂ and Ethyl alcohol along with 56 K. cals of energy.

Question 20.
Describe the tissue culture technique. What are the advantages of tissue culture over conventional method of plant breeding in crop improvement programmes?
Answer:
Tissue culture techniques: It involves
a) Preparation of Nutrient medium: The nutrient medium is a mixture of various essential nutrients, Amino acids, vitamins, and carbohydrates. These are mixed in distilled water and P^H is adjusted to 5.6 to 6.0 growth regulators like auxins, and cytokinins are added to the medium. The nutrient medium is powered in glass vessels and closed tightly with cotton plugs before sterilizing them in an Autoclave.

b) Sterilisation: The nutrient medium is rich in nutrients and therefore attacks the growth of microorganisms. The culture
medium is autoclaved for 15 mins at 121°C or 15 pounds of pressure to make aseptic.

c) Preparation of explant: Any living of plant can be used as explant. The explants must be cleaned with liquid detergent
and in running water and surface sterilised with sodium hypochlorite and rinsed with distilled water.

d) Inoculation of explants: The transfer of explants onto the sterilized nutrient medium is called inoculation. It is carried out under sterilized conditions.

e) Incubation: The culture vessels with inoculated explants are incubated in a culture room under controlled temperature, optimum light and humidity. The cultures are incubated for 3 – 4 weeks, the cells of the explants divide and redivide, producing a makes of tissue called callus. The callus is transferred to another medium containing growth regulators, to initiate the formation of roots and leafy shoot. Sometimes embryo-like structures develop directly from the callus which are referred as somatic embryos. These can be encapsulated with sodium alginate to form synthetic or artificial seeds.

f) Accianiatization and transfer to pots: The plants produced through tissue culture are washed gently and are planted in pots kept in glass house for 1-2 weeks. Finally, they are transferred to field.

Advantages:

1. More number of plants are produced within a short period and in a little space. (Micropropagation).
2. Virus-free plants are produced through meristem culture.
3. Somacloned variations in plants and used in plant breeding.
4. Synthetic or artificial seeds are produced by encapsulation of embryoids with sodium alginate.
5. The production of exact copies of plants that produce particularly good flowers, and fruits.
6. To quickly produce mature plants.
7. The production of multiples of plants in the absence of seeds or necessary pollinators to produce seeds.
8. The regeneration of whole plants from plant cell that have been genetically modified.
9. Virus-free plants are used as cleaned stock for horticulture.

Question 21.
Give a brief account of the tools of recombinant DNA technology.
Answer:
Restriction enzymes: Two enzymes responsible for restricting the growth of Bacteriophage in Escherichia coli were isolated in the year 1963. One of these added methyl group to DNA and the other DNA. The latter was called restriction endonuclease. The first restriction endonuclease. Hind II which cut DNA molecule at a particular pair by recognising a specific sequence of six base pairs, called recognition sequence for Hind II. Today more than 900 restriction enzymes were isolated from over 200 strains of Bacteria each of which recognises a different recognition sequence.

E. CORI is a restriction enzyme in which, the first latter comes from the genus (Escherichia) and the second two latter from the species of the prokaryotic cell (cou) the latter R’ is derived from the name of strain. Roman numbers indicate the order in which the enzymes were isolated from the strain of Bacteria. Restriction enzymes belong to a larger class of enzymes called nucleases. They are of two types:

• Exonucleases which remove nucleotides from the ends of the DNA.
• Endonucleases which makes cuts at specific locations within the DNA.

Most restriction enzymes cut the two stands of DNA double helix at different locations such a cleavage is known as staggered cut. E. CORI recognises 5’ GAATT3’ sites on the DNA and cut it between G and A results in the formation of sticky ends or cohesive end pieces. This stickyness of the ends facilitates the action of enzyme DNA ligase.

Cloning vectors: The DNA used as a camer for transferring a fragment of foreign DNA into a suitable host is called vector. Vectors used for multiplying the foreign DNA sequences are called cloning vectors. Commonly used cloning vectors are plasmids, bacteriophages, cosmids, plasmids are extra-chromosome circular DNA molecules present in almost all bacteria species. They are inheritable and carry few genes are easy to isolate and reintroduce into the bacteria (host).

Features required to facilitate cloning into a vector:
a) Origin of replication: (oil) This is a sequence from where replication starts and any piece of DNA when linked to this
sequence can be made to replicate within host cells. It is also responsible for controlling the copy number of the linked DNA.

b) Selectable marker: In addition to ‘on’ the vector requires a selectable maker, which help in identifying and eliminating non-transformants and selectively permitting the growth of the any transformants normally, the genes encoding resistance to Antibiotics such as Ampicillin, Chloramphenicol tetra cycline or Kanamycin, etc., are useful selectable markers for E. Coli.

c) Cloning sites: In order to link th alien DNA, the vector needs to have very few preferably single recognition sites for the restriction enzyme.

d) Molecular Weight: The cloñing vector should have low molecular weight.

e) Vectors for cloning genes in plants and animals: The tumour-inducing (ri) plasmid of Agrobacterium tunifaciens
has now been modified into a cloning vector such that it is no more pathogenic to plants. Similarly, retroviruses have also been disarmed and are now used to deliver desirable genes into animal cells.