Previous Solved GATE Life Science Questions - Botany

Previous question papers

 1. Which of the following acts as a precursor of IAA biosynthesis?

(a) Methionine

(b) Putrescine

(c)Tryptophan

(d) Geranyl geranyl pyrophosphate

Ans: Tryptophan
More about, Auxins

2. Identify the incorrect one

(a) GA involves in flowering

(b) Auxin helps in cell elongation and formation of root

(c) Ethylene is produced during the ripening of seeds

(d) Cytokinin helps in embryo development and prevents leaf senescence

Ans: Ethylene is produced during the ripening of seeds
More about, Phytohormones

3. Which of the following factors is critical for haploidy induction?

(a) Induction and proliferation of callus from anther culture

(b) Use of Colchicine in the medium

(c) Treatment of donar plants with phytohormones

(d) Presence of optimum levels of auxin and cytokinins in the medium

Ans: Induction and proliferation of callus from anther culture

• Haploid production mainly by anther culture
• Colchicine for polyploidy induction
• Presence of optimum levels of auxin and cytokinins in the medium: for rooting and shooting

4.  Availability of free energy is maximum in which of the following trophic levels?

         (a) Producers

(b) Decomposers

(c) Herbivores

(d) Secondary Consumers

Ans: Producers

5. Identify the mismatch tissue

(a) Periderm

(b) Phelloderm

(c) Palisade

(d) Phellem

Ans: Palisade

• Periderm, phelloderm and phellem : associated with secondary growth of plants (cork formation)
• Palisade: elongated chloroplast rich cells of leaf                                                              

6. The development of embryos from the cells of nucellus or integument is known as

a) Apogamy

b) Apospory

c) Parthenogenesis

d) Adventive embryony

Ans:  Adventive polyembryony

• Apogamy: a sexual reproduction in plants without fertilization or meiosis
• Apospory: development of diploid embryosac by the somatic division of nucellus or integuments cells without meiosis
• Parthenogenesis: development of an individual from an egg without fertilization
•  Adventive embryony: embryonic development without fertilization from cells that are not egg cells

7. When the gynoecium is present in the top most position of thalamus the flower is known as

a) Epigynous

b) Hypogynous

c) Perigynous

d) Inferior

Ans: Epigynous : Thalamus grow upwards and ovary inferior

• Hypogynous: ovary superior and thalamus bears ovary in topmost position
• Perigynous: Thalamus grow upwards and ovary half inferior

8. Synthesis of DNA polymerase occurs at

a) G₁

b) S

c) G₂

d) M

Ans: b) S

• S stands for synthetic phase, DNA synthesis requires DNA polymerase enzyme

9. Synthetic seed is produced by encapsulating somatic embryos with

a) Sodium alginate

b) Sodium nitrate

c) Sodium acetate

d) Sodium sulphate

Ans: Sodium alginate

• Artifical seeds are the living seed-like structure which are made experimentally by a technique where somatic embryoids are encapsulated by a hydrogel.
• Method: Somatic embryoids are mixed with Sodium alginate (0.5-5%) and dropped into calcium nitrate solution (30-100µM)

10.  Change from purine to pyramidine or pyramidine to purine is

a)  Transition

b) Transversion

c) Frame shift

d) Reversion

Ans: Transversion

• Transversion: substitute one purine for a pyramidine or vice versa
• Transition: substitute one purine for another purine or one pyramidine for another pyramidine
• Frame shift mutation: a shift of the reading frame caused by the deletion or insertion of one or a few nucleotides