Tag: multicellular structure: tissue

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Questions Related to multicellular structure: tissue

Multiple choice biology multicellular structure: tissue defense mechanism in plants epidermal tissue system kinds of plant tissue permanent tissues and their types

Which of the following contiguous cells lack middle lamella?

  1. All epidermal cells

  2. Guard and subsidiary cells

  3. Subsidiary cells

  4. Guard cells
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Epidermal cells are typically tightly packed and lack a middle lamella between them in the same way that parenchyma or other tissues do, as they are often directly adjacent.

Multiple choice biology multicellular structure: tissue defense mechanism in plants epidermal tissue system kinds of plant tissue permanent tissues and their types

Why is epidermis important for the plants?

  1. It gives protection

  2. It helps in gaseous exchange

  3. It checks water loss

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

  • Epidermis is the outermost layer of the plant body. It carries out functions as follows:
1. It covers the body from outside and protects from pathogen attack and atmosphere changes.  
2. It shows the presence of stomata (minute pore-like structure) on leaves. Stomata are involved in gaseous exchange (oxygen, carbon dioxide) with the atmosphere. It also shows the presence of lenticels on the woody stem for gaseous exchange. 
3. The stomata present on leaves are also involved in transpiration (water evaporation from plant body). Stomata are guarded by guard cells, which close and open the stomata as per requirement. Therefore, epidermis bearing stomata also check for water loss from the plant body. 
4. The epidermis is protected by cuticle at some parts of the tree and it helps to stop water loss by evaporation.

Multiple choice biology multicellular structure: tissue defense mechanism in plants epidermal tissue system kinds of plant tissue permanent tissues and their types

Cork cells posses ...................... on their walls that makes it impervious to gases and water.

  1. Suberin

  2. Lignin

  3. Pectin

  4. Hemicellulose
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

  • Lignin is a substance, which is impermeable to water. It is absent in cork cells.
  • Pectin is not present in cork cells. 
  • Hemicellulose is permeable to water and gases.
  • Cork cells are dead and have cell walls composed of a waxy substance "suberin", which is highly impermeable to gases and water. This substance prevents water loss from the stem. 

So, the correct answer is option A. 

Multiple choice biology multicellular structure: tissue defense mechanism in plants epidermal tissue system kinds of plant tissue permanent tissues and their types

Motor cells help in

  1. Inward rolling of leaves

  2. Transpiration

  3. Guttation

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Bulliform cells or motor cells are large, bubble-shaped epidermal cells that occur in groups on the upper surface of the leaves of many grasses. Loss of turgor pressure in these cells causes leaves to roll up during water stress. During drought, the loss of moisture through vacuoles induces bulliform cells to cause the leaves of many grass species to close as the two edges of the grass blade fold up toward each other. Once adequate water is available, these cells enlarge and the leaves open again. Folded leaves offer less exposure to sunlight, so they are heated less thus, reducing evaporation and conserving the remaining water in the plant and occur on the leaves of many monocotyledons but are probably best known in grasses. They are thought to play a role in the unfolding of developing leaves and in the rolling and unrolling of mature leaves in response to alternating wet and dry periods. So, motor cells helps in inward rolling of leaves and not in transpiration or guttation. 
Thus, the correct answer is option A.

Multiple choice biology multicellular structure: tissue defense mechanism in plants epidermal tissue system kinds of plant tissue permanent tissues and their types

The term periderm is used to include

  1. Cortex

  2. Secondary cortex

  3. Both of the above

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The periderm is the secondary protective dermal tissue that replaces the epidermis during growth in thickness of stems and roots of gymnosperms and dicotyledons i.e., secondary growth. 

Unlike typical epidermis, the periderm is a multilayered tissue system, the bulk of which usually constitutes the cork or phellem. It has cortex, secondary cortex.

Multiple choice biology multicellular structure: tissue defense mechanism in plants epidermal tissue system kinds of plant tissue permanent tissues and their types

Which of the following sclereids are the characteristic of intercellular spaces of Nymphaea?

  1. Osteosclereids

  2. Brachysclereids

  3. Macrosclereids

  4. Astrosclerieds
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Astrosclerieds is a sclereid having its cell wall drawn out into lobes or arms to form a more or less stellate body. It is found in certain xerophytes. Nymphaea contains large intercellular spaces, which occur in the petiole. These airspaces are surrounded by long columns of parenchyma cells. The columnar cells contain chloroplasts and are presumably photosynthetic. Part of a large astroscleried can be seen cutting across one of the parenchymatous fingers. These sclereids add some mechanical strength to fragile structure. 

Multiple choice biology multicellular structure: tissue defense mechanism in plants epidermal tissue system kinds of plant tissue permanent tissues and their types

In grasses, certain adaxial epidermal cells along the veins modify themselves into large empty, colourless cells, called as

  1. Bulliform cells

  2. Companion cells

  3. Guard cells

  4. Subsidiary cells

  5. Albuminous cells
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Bulliform cells  are so called because of its peculiar bubble shape. It mainly occurs on the upper surface of the leaves present in grasses. Water present in these cells helps to maintain its shape but loss of turgor pressure during the stress allows the leaves to roll up. During drought, the loss of moisture through vacuoles induces bulliform cells to cause the leaves of many grass species to close as the two edges of the grass blade fold up toward each other. Once adequate water is available, these cells enlarge and the leaves open again. 

Companion cells are specialized parenchyma cell, located in the phloem of flowering plants and closely associated with development and function with a sieve-tube element. 
Guard cells are cells surrounding each stoma. They help to regulate the rate of transpiration by opening and closing the stomata. 
The stoma is protected by subsidiary cells that have papillae that arch across the stoma, creating a mini-depression. This will tend to retain escaped water, giving it time to diffuse back into the stoma instead of being immediately blown away by a breeze. 
Albuminous cells have a similar role to companion cells, but are associated with sieve cells only and are therefore found only in seedless vascular plants and gymnosperms. 
So, the correct answer is option A.

Multiple choice biology multicellular structure: tissue defense mechanism in plants epidermal tissue system kinds of plant tissue permanent tissues and their types

How many tissue systems are suggested by Sachs?

  1. Two

  2. Three

  3. Four

  4. Five
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Two or more tissues together constitutes the tissue system. The activities of the constituent tissues are responsible for the major function, although they are different in structure and origin. All the different type of tissues in a plant that perform the similar basic function, irrespective of their location is known as tissue system. 

Sachs (1875), recognized three types of tissue system in plants: 
1. Epidermal or Dermal Tissue System 
2. Cortical or Fundamental or Ground Tissue System. 
3. Vascular Tissue System. 
So, the correct answer is 'Three'

Multiple choice biology multicellular structure: tissue defense mechanism in plants epidermal tissue system kinds of plant tissue permanent tissues and their types

In respect of many grasses, the presence of motor cells in the upper epidermis of leaves is to

  1. Increase the surface area of the leaf

  2. Store large amount of water

  3. Check transpiration by reducing the surface area of the leaf

  4. Bear unicellular trichomes
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Bulliform cells or motor cells are large, bubble-shaped epidermal cells that occur in groups on the upper surface of the leaves of many grasses. Loss of turgor pressure in these cells causes leaves to roll up during water stress. During drought, the loss of moisture through vacuoles induces bulliform cells to cause the leaves of many grass species to close as the two edges of the grass blade fold up toward each other. Once adequate water is available, these cells enlarge and the leaves open again. Folded leaves offer less exposure to sunlight, so they are heated less thus, reducing evaporation and conserving the remaining water in the plant and occur on the leaves of many monocotyledons but are probably best known in grasses
So, the correct answer is 'Check transpiration by reducing the surface area of the leaf'
Multiple choice biology multicellular structure: tissue defense mechanism in plants epidermal tissue system kinds of plant tissue permanent tissues and their types

The stems and leaves of grasses are rough due to

  1. Calcium carbonates

  2. Resins

  3. Silica

  4. Calcium oxalate
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The grass leaves are linear in shape and sessile and are rough in texture due to the presence of cork cells in the epidermis and deposition of silica material. The process of deposition of silica material over the epidermis is known as silicification. It checks the transpiration rate and prevents the entry of pathogens and gives stiffness to the lamina.

So, the correct answer is option C.