Biology Multiple Choice Questions and Answers for Different Competitive Exams

MCQ on Plant Hormones - Auxins

1. The term auxin was coined by
a) Skoog
b) Haberlandt
c) Miescher
d) F.W. Went

2. Precursor of Indole acetic acid (natural auxin) is
a) Glycine
b) Methionine
c) Isopentynyl pyrophosphate
      d) Tryptophan

3. All the following hormones are growth inhibitors except
a) Absiccic acid
b) dormin
c) ethylene
      d) IAA

4. Which of the following is a gaseous hormone
a) IBA
b) NAA
c) Abscicic acid
d) Ethylene

5. Which of the following is widely used as a rooting hormone

Auxins
a) NAA
b) 2,4, D
c) 2,4,5-T
d) cytokinnin

6.  “Agent orange” the leaf defoliator used by USA in Vietnam war was  
a) ethylene
b) 2,4,-D and 2,4,5-T
c) 2,4,-D and NAA
d)  2,4,5-T, NAA and ethylene

7. All the following inhibits auxin transport (anti-auxins) except
a) Cytokinnin
b) α naphthyl thalamic acid
c) 2,3,5-tri iodo benzoic acid
d) ethylene

8. Which of the following auxin is widely used as a selective weedicide
a) IBA
b) 2,4,-D
c) NAA
d)  2,4,5-T

9. All are synthetic auxins except
a) NAA
b) IAA
c) 2,4,-D
d) 2,4,5-T

10. Auxin transport is
a) polar
b) non-polar
c) symplast
d) apoplast

11. Which of the following bioassays are used to detect the presence of auxin
a) Avena curvature test and tobacco pith culture
b) Split pea stem curvature test and tobacco pith culture
c) Avena curvature test and Split pea stem curvature test
d) tobacco pith culture only

12.  Which of the following is not a function of auxin
a) inducing dormancy
b) enhancing cell division
c) inducing callus formation
d) maintaining apical dominance

13.  Nodule formation is induced by
a) IBA
b) IAA
c) Both (a) and (b)
d) NAA

14.  All are natural auxins except
a) IAA
b) Phenoxy acetic acid
c) Indole-3-acetic acid
d) NAA

15. Which of the following is an auxin receptor
a) ETR1
b) CBP1
c) ABP1
d) GRE

Abbreviations used: 
* ABP: auxin binding protein 1
* GRE: giberillin responsive element
* NAA: naphthalene acetic acid
* IAA: indole acetic aicd
* TIBA: tri iodo benzoic acid
* 2,4,-D: 2,4-dichloro phenoxy acetic acid
Answers:
1-d
2-d
3-d
4-d
5-a
6-b
7-a
8-b
9-b
10-a
11-c
12-a
13-b
14-d
15-c

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