Tag: botany

Quizzes (264) Questions (5276)

Questions Related to botany

Multiple choice botany plant physiology mineral absorption transport of food, water and minerals mineral transport theories of translocation transport in the phloem of plants

How many of the following features are related to Dixon and Jolly model of water transport in plants?
a. Cohesion between water molecules
b. Transpiration pull
c. Pushing of water by negative root pressure
d. Surface tension
e. Pushing of water by positive root pressure.

  1. $4$
  2. $5$
  3. $2$
  4. $3$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The Dixon and Jolly model (Cohesion-Tension theory) relies on cohesion, adhesion, surface tension, and transpiration pull. Pushing by root pressure is not part of this specific model.

Multiple choice botany internal structure of root, stem and leaf internal structure of monocot leaf internal structure of leaf (dicot and monocot) anatomy of leaf

In monocot leaves, the mesophyll Consists of

  1. Aerenchyma

  2. Only Spongy chlorenchyma

  3. Only Palisade Chlorenchyma

  4. Palisade and Spongy Chlorenchyma
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Mesophyll in monocot leaves lie between the two layers of epidermis and is not differentiated in palisade and spongy tissues. Instead, the undifferentiated mesophyll is similar to spongy tissue. It consists of the mesophyll cells that are chlorenchymatous and contain a number of chloroplasts. 
So the correct answer is 'Only spongy chlorenchyma'.
Multiple choice botany internal structure of root, stem and leaf internal structure of monocot leaf internal structure of leaf (dicot and monocot) anatomy of leaf

Cells which help in rolling and unrolling of leaf lamina in grasses are 

  1. Complementary cells

  2. Motor cells

  3. Passage cells

  4. Companion cells
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • The leaves of monocots have a large bubble-shaped epidermal cell called bulliform cells.
  • They are also known as motor cells.
  • They are present in the adaxial surface of the leaves.
  • They play an important role in the unfolding of the developing leaves and in the rolling and unrolling of mature leaves in response to the alternating wet and dry conditions.
  • So, the correct answer is 'Motor cells'.
Multiple choice botany internal structure of root, stem and leaf internal structure of monocot leaf internal structure of leaf (dicot and monocot) anatomy of leaf

Select the true statement for a isobilateral leaf.

  1. The stomata are present on both the surfaces

  2. Mesophyll is differentiated into palisade & spongy

  3. Cuticle is always absent on both surfaces

  4. Vascular bundles are open & conjoint
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Monocot leaves are called isobilateral leaves since both the sides of monocot leaves are more or less similar. Isobilateral leaves orient themselves parallel to the main axis and parallel to the direction of sunlight. Epidermis is single layered, present on both surfaces and has cuticles (cuticularized) and stomata on both surfaces (amphistomatic). It  is composed of compactly arranged oval or barrel shaped thin walled parenchymatous cells. Mesophyll is the ground tissue that is present between the two epidermal layers. Vascular bundles are of two types- small bundles are abundant and larger bundles are found in between them.

So the correct option is 'the stomata are present on both the surfaces'.

Multiple choice botany internal structure of root, stem and leaf internal structure of monocot leaf internal structure of leaf (dicot and monocot) anatomy of leaf

The number of types of cells presents in the adaxial epidermis of grasses

  1. $1$
  2. $2$
  3. $3$
  4. $4$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The upper surface of the leaf is known as the adaxial surface. The type of cells presents in the adaxial epidermis of grasses is bulliform cells (only one type). These are large bubble-shaped cells present in the adaxial or upper surface of the leaves in monocots. So, the correct answer is '1'.

Multiple choice botany internal structure of root, stem and leaf internal structure of monocot leaf internal structure of leaf (dicot and monocot) anatomy of leaf internal structure of dicot leaf

Match the columns.

A) Syntheticauxin  i) Zeatin 
B) Natural cytokinin from coconut milk  ii) IBA
C) naturalauxin  iii) Kinetin 
D) purine from herring sperm DNA iv) NAA
  1. $A-iv,B-i,C-ii,D-iii$
  2. $A-ii,B-i,C-iv,D-iii$
  3. $A-iv,B-iii,C-ii,D-i$
  4. $A-ii,B-iii,C-iv,D-i$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
 A synthetic auxin (NAA) suppresses secondary wall cellulose synthesis and enhances elongation in cultured cotton. Zeatin is a cytokinin derived from adenine, which occurs in the form of a cis- and a trans-isomer and conjugate. Five naturally occurring (endogenous)auxins in plants include indole-3-acetic acid, 4-chloroindole-3-acetic acid, phenylacetic acid, indole-3-butyric acid, and indole-3-propionic acid. The mechanism of production of kinetin in DNA is thought to be via the production of furfural — an oxidative damage product of deoxyribose sugar in DNA — and its quenching by the adenine base's converting it into N6-furfuryladenine, kinetin. So the correct option is
 ' A−iv,B−i,C−ii,D−iii'.
Multiple choice botany internal structure of root, stem and leaf internal structure of monocot leaf internal structure of leaf (dicot and monocot) anatomy of leaf internal structure of dicot leaf

Mark out the incorrect statements.


A) Bulliform cells are found on adaxial epidermis of grasses.
B) All vascular bundles have different size in leaf showing parallel venation.
C) Endodermis, pericycle, vascular bundle and pith constitute the stele.
D) Bastfibresare absent in primary phloem.

  1. B only

  2. D only

  3. A & B only

  4. B & C only
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Generally, the patterns of the leaf veins, or vascular bundles are pinnate and the veins are free; that is, they all diverge and never coalesce, either along their sides or at the ends. So, the incorrect statement is all vascular bundles have different size in leaf showing parallel venation.

Multiple choice botany internal structure of root, stem and leaf internal structure of monocot leaf internal structure of leaf (dicot and monocot) anatomy of leaf internal structure of dicot leaf

Dorsiventral leaf is identified by the presence of

  1. Stomata on both the epidermis

  2. Stomata mainly present on the lower epidermis

  3. No stomata on the epidermis

  4. Sunken stomata on the upper epidermis
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In dorsiventral leaf, epidermis is in two layers, one on each surface of the leaf. Both the layers are composed of compactly arranged, barrel-shaped cells. Intercellular spaces are absent. A cuticle surrounds both the layers. Multicellular hairs called as trichomes are present on both the layers. Stomata occur only in the lower epidermis. This condition is described as hypostomatic. 

Mesophyll is the ground tissue that occurs between the two epidermal layers. It is exclusively composed of chlorenchyma cells. The mesophyll is characteristically differentiated into two regions, namely an upper palisade parenchyma and a lower spongy parenchyma. Thus, option B is correct.