MCQs on Botany for Competitive Exams

MCQs on Botany for competitive exams

In prokaryotes... the lagging primers are removed by:

(a) 3' to 5' Exonuclease
(b) DNA ligase
(c) DNA POL I ✅
(d) DNA POL III

Synthesis of mRNA on DN A template is:

(a) unidirectional ✅
(b) bidirectional
(c) bidirectional with the help of primer
(d) unidirectional with the help of primer

Which one of the following statement about E. coli RNA polymerase is false

(a) The Holoenzyme include the sigma factor
(b) The core enzyme include the sigma factor ✅
(c) It requires Mg2+ for its activity
(d) It requires Zn2+ for its activity

The DNA binding protein that initiates the transcription of bacterial gene is called

(a) Operator
(b) Promoter
(c) Repressor
(d) Sigma factor ✅

Pribnow box is centered at

(a) +10 position
(b) -10 position ✅
(c) +35 position
(d) -35 position

Mode of action of rifampicin in E. coli is through

(a) Cell division
(b) Initiation of transcription ✅
(c) RNA polymerase binding to DNA template
(d) Inhibition of the oxidation potential

The Exonuclease activity of DNA polymerases function to

(a) Remove the RNA primer sequence
(b) Proofread the new DNA strand and remove in appropriate nucleotides
(c) Maximize the Fidelity of DNA replication
(d) All of the above ✅

Formylmethionine tRNA is present in

(a) Yeast
(b) Bacteria ✅
(c) Insects
(d) Mammal

Chloramphenicol inhibits

(a) Cell wall synthesis in bacteria
(b) Protein synthesis on 70S ribosome ✅
(c) Protein synthesis on 80S ribosome
(d) DNA replication

Which of the fallowing hypothesis best explain the occurrence of Himalayan flora of western ghats of India

(a) Continental drift theory.
(b) Deccan trap theory.
(c) Himalayan glaciation theory ✅
(d) Coromandel coast.

Chinese brake fern (Pteris vittata) is hyperaccumulators of?

(a) Cadminum
(b) Arsenic ✅
(c) Lead
(d) Chromium

In which ecosystem is the detrital pathways of energy flow most important ?

(a) Lakes
(b) Grassland
(c) Tropical rainforests ✅
(d) Ocean

MCQs on Botany

MCQs on Botany for Competitive Exams

Which of the fallowing is likely to contribute to the stability of an ecosystem.?

(a) High number of specialists
(b) Fewer number of functional link
(c) More omnivores ✅
(d) Linear rather than reticulated food weds.

Which of the following period is known as ‘Ages of fishes’?

(a) Devonian ✅
(b) Jurassic
(c) Cambrian
(d) Carboniferous.

Which gas does not contributes to global warming through its greenhouse effect?

(a) Nitrous oxide.
(b) Methane.
(c) Carbon dioxide
(d) Nitric oxide ✅

Which one of the following statement regarding seed germination of a wild_type plant is not correct

(a) Low ABA and high bioactive GA can break seed dormancy.
(b) Light accompanied with high temperature can break seed dormancy ✅
(c) GA induces synthesis of hydrolytic enzyme in cereal grains
(d) Degradation of carbohydrate enzyme and storage protein provide nourishment and energy to support seedling growth.

The plant hormone indole-3-acetic acid is present in most plant.the structure of this hormone is related to which one of the following amino acid

(a) Glutamic acid
(b) Aspartic acid
(c) Lysine
(d) Tryptophan ✅

Which of the following mechanism is not involved in providing photoprotection to plant?

(a) Degradation of D1 protein
(b) Zeaxanthin formation
(c) Photolysis of water ✅
(d) Thermal dissipation

Which one of the following compound is generally translocated in the phloem?

(a) Sucrose ✅
(b) D-glucose
(c) D-mannose
(d) D-fructose

Which one of the following is the correct order of electron transport during light reaction in the thylakoid membrane of chloroplast?

(a) P680 → cytochrome b6f → PC → PQ
(b) p680 → PC → cytochrome b6f → PQ
(c) P680 → PQ → cytochrome b6f → P700
(d) P680 → PQ → cytochrome b6f → PC ✅

Which one of the following is not the main factor that contribute to water potential during plant growth under normal condition?

(a) Solute potential
(b) Hydrostatic pressure
(c) Gravity
(d) Temperature ✅

The quantum yield of oxygen evolution during photosynthesis drastically drops in far-red light.this effect is known as;

(a) Red drop ✅
(b) Far red drop
(c) Blue drop
(d) Visible spectrum drop

The plant hormone, gibberellic acid is generally not associated with

(a) Stem elongation
(b) Parthenocarpy
(c) Parthenogenesis ✅
(d) Malt production

Which of the following describes the function of silicon in plant?

(a) Constitutes of amino acid.
(b) Contributes to cell wall rigidity and elasticity ✅
(c) Constituent of the photosynthesis reaction centre
(d) Maintenance of cell turgor and electroneutrality

In certain plant,the mechanism where timing of anther dehiscence and stigma receptivity do not coincide to avoid self-pollination Is called

(a) Dichogamy ✅
(b) Herkogamy
(c) Monoecy
(d) Dioecy

Which of the following is not prosthetic group of nitrate reductase?

(a) FAD
(b) HEME
(c) Mo
(d) Pterin ✅

Due to which reaction PGA is changed into phosphoglyceraldehyde in photosynthesis process ?

(a) Oxidation
(b) Reduction ✅
(c) Electrolysis
(d) Hydrolysis

In photosynthesis process,how many molecules of NADPH & ATP are required to reduce six molecules of carbon dioxide to glucose?

(a) 3ATP & 3NADPH
(b) 6ATP & 6NADPH
(c) 12ATP & 18NADPH
(d) 18ATP & 12NADPH ✅

Which vitamin is required for the synthesis of co-factor ,required in conversion of succinate to fumarate?

(a) Riboflavin ✅
(b) Thiamine
(c) Lipoic acid
(d) Niacin

Which process does not involve cytochrome -c?

(a) Apoptosis
(b) TCA cycle ✅
(c) Electron transport
(d) Oxidative phosphorylation

Which enzyme is inhibited by arsenate ?

(a) Glyceraldehyde -3 phosphate dehydrogenase ✅
(b) Lactate dehydrogenase
(c) Hexokinase ✅
(d) Phosphofructokinase

Fluoride inhibits which glycolytic enzyme?

(a) Enolase ✅
(b) Glucokinase
(c) Phosphofructokinase
(d) Lactate dehydrogenase

Which glycolytic enzyme is used in gluconeogenesis?

(a) Pyruvate kinase
(b) Glucokinase
(c) Aldolase
(d) Phosphoglycerate kinase ✅

Which of the following connects the glycolysis and Krebs cycle

(a) Pyruvic acid
(b) Glucose
(c) Acetyl Co-A ✅
(d) ATP

Tropical plants like maize show high efficiency of CO2 fixation because of

(a) TCA cycle
(b) EMP pathway
(c) Hatch-slack pathway ✅
(d) Calvin cycle

If intensity of light increases 20 times ,the rate of photosynthesis will -

(a) Increase
(b) Constant
(c) Decrease
(d) Increase till feedback inhibition ✅

In India tropical rain forest occurs in.

(a) Jammu and kashmir
(b) Andaman and Nicobar ✅
(c) Uttar Pradesh
(d) Himachal Pradesh

Plants that grows in saline water lodged habitat are called

(a) Xerophytes
(b) Halophytes
(c) Mangroves ✅
(d) Mesophytes

Green house effect with respect of global warming refers to

(a) Cooling and moist condition
(b) Warming effect ✅
(c) Increased rainfall greenery
(d) Desertification.

High BOD value in aquatic environment is indicative of

(a) A pollution free system
(b) A highly polluted system due to excess of nutrients ✅
(c) A highly polluted system abundant heterotrophs
(d) A highly pure water with abundance of autotrophs

Monocotyledons are placed before dicotyledons in the classification proposed by:

(a) Bentham and Hooker
(b) Engler and Prantl ✅
(c) Hutchinson
(d) Rendle

Which of the following conditions in the flower is considered to be primitive?

(a) Hypogyny ✅
(b) Perigyny
(c) Epigyny
(d) Agyny

Who proposed the classification of plants based on sex?

(a) Takhtajan
(b) Bentham and hooker
(c) Linnaeus ✅
(d) Hutchinson

Members of Asclepiadaceae differ from Apocynaceae in having :

(a) Latex
(b) Corona
(c) Translators ✅
(d) Bicarpillary ovary

Cyathium inflorescence is the characteristic of the family:

(a) Malvaceae
(b) Euphorbiaceae ✅
(c) Brassicaceae
(d) Compositae

When stamens are connate by their anthers and their filaments remain free, this condition is known as :

(a) Synandrous
(b) Syngenesious ✅
(c) Diadelphous
(d) Epipetalous

Which of the following is not correctly matched?

(a) Solanum melongena - onion ✅
(b) Raphanus sativus - radish
(c) Capsicum annuum - chillies
(d) Prunnus persica - peach

Marginal placentation is seen in which of the following families?

(a) Brassicaceae
(b) Fabaceae ✅
(c) Rutaceae
(d) Nymphaeaceae

The lemmas in family Poaceae are characterized by the presence of

(a) Awn ✅
(b) Glume
(c) Palea
(d) Spike

Which of the following is the second largest family of the Indian flora?

(a) Rosaceae
(b) Polygonaceae
(c) Orchidaceae ✅
(d) Brassicaceae

First published on 18-04-2021
Last updated on 20-04-2021

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