Anatomy of Plants MCQ Quiz in मल्याळम - Objective Question with Answer for Anatomy of Plants - സൗജന്യ PDF ഡൗൺലോഡ് ചെയ്യുക

Concept:

• Epidermis is the layer of cells present on the outside of plant structures such as stem, root, leaf, flower, fruit and seed.
• Epidermis comprises pavement cells, guard cells and subsidiary cells.
• Functions - 
  • Provides a barrier against water loss, infection and mechanical injury.
  • Helps regulate gas exchange.
  • Regulates transpiration.
  • Increases water absorption, etc.

Important Points

• Hair-like projections that extend from the epidermis are called trichomes.

Trichomes - 

• ​Trichomes are referred to as leaf hair.
• These can be singular or multicellular.
• The shape of trichomes helps in identifying a plant species.
• Trichomes are controlled by trichome specificity genes.
• The chemicals produced by trichomes in their glandular tips protect the plant from being eaten by insects.
• Apart from this, trichomes also produce secondary chemicals that are used as useful products such as fragrances and flavors.
• Some trichomes also contain irritants that can cause rashes in humans.
• In insectivorous plants like Drosera, trichomes secrete exudate that helps in trapping the prey.​

So the correct answer is option 4 (Trichomes).

Key Points

• Epithelial tissue or epithelium is a type of animal tissue that is found covering the outer surface of the body or organs. It is also present as a lining of the various ducts and tubes inside the body.
• It has a free surface that faces either a body fluid or an outside environment.
• The cells of the epithelial tissue lie on a thin layer of supportive tissue membrane called the basement membrane.
• There is no intercellular space between the compactly placed cells of the epithelial tissue.
• Epithelial tissue does not have blood vessels. Hence it is non-vascular.
• The main function of epithelial tissue is to protect other tissues.
• It may perform different functions depending on its location. E.g. Absorption in the digestive system, Secretion in gland cells, etc.
• Epithelial tissue has great regeneration power.
• There are two main types of epithelial tissue depending on the number of layers - Simple epithelium and Compound (Stratified) epithelium.

1. Simple epithelium:

• It is made up of a single layer of cells.
• It functions as a lining for the body cavity, ducts and tubes in the body.
• Simple epithelium is further divided into the following types: 
  1. Squamous epithelium
  2. ​Cuboidal epithelium
  3. Columnar epithelium
  4. ​Ciliated epithelium
  5. Glandular epithelium​​

2. ​​​Compound epithelium:
   • ​It is made up of more than one layer of cells.
   • The main function of compound epithelium is to protect other cells.

Explanation:

• a - always ciliated
  • This option is incorrect with regard to epithelial tissue.
  • Not all types of epithelial tissues bear cilia.
  • Ciliated epithelium is a type of epithelial tissue that bears cilia.
• b - non-vascular
  • This option is correct with regard to epithelial tissue.
  • Epithelial tissues do not have blood vessels.
  • Hence it can be regarded as non-vascular.
• c - with lots of extracellular material​
  • This option is incorrect with regard to epithelial tissue.
  • Epithelial tissues have scanty extracellular material.
  • The extracellular matrix consists of mainly the thin membrane - basement membrane. 
• d -  tightly packed​
  • This option is correct with regard to epithelial tissue.
  • The cells of the epithelial tissue are compactly packed with no intercellular space.

So the correct answer is option 2 - (b) + (d).

The correct answer is (i) and (ii)

Explanation:

• Isobilateral leaves have nearly identical structure on both sides, with mesophyll tissues (palisade and spongy parenchyma) similar on both adaxial (upper) and abaxial (lower) surfaces.
• In isobilateral leaves, stomata are often distributed equally on both surfaces, which facilitates gas exchange.
• Bulliform cells, located on the adaxial epidermis in grasses, are large, bubble-shaped cells that help in the folding and unfolding of leaves to reduce water loss during dry conditions.
• Statement (i): Correct. Stomata are equally distributed on both surfaces in isobilateral leaves.
• Statement (ii): Correct. Bulliform cells are a distinctive feature in the adaxial epidermis of grasses.
• Statement (iii): Incorrect. In leaves, vascular bundles are usually collateral (xylem and phloem located on the same radius), not radial.
• Statement (iv): Incorrect. In a typical isobilateral leaf, the phloem is not specifically adaxially placed; it is usually located outside the xylem in the vascular bundle.

Fig: T.S. of leaf (Monocot)

The correct answer is thalamus

Explanation

Epicarp: This is the outermost layer of the pericarp (fruit wall), commonly known as the skin or peel of the fruit. For example, in apples and pears, the epicarp is the outer skin that you see and touch.
Mesocarp: The mesocarp is the middle layer of the pericarp, usually the fleshy and often the most substantial part of the fruit. In some fruits like peaches and mangoes, the mesocarp is the juicy, edible portion.
Endocarp: This is the innermost layer of the pericarp, which directly surrounds the seed(s). It can be hard or stony in some fruits like peaches and cherries (forming the pit), or it can be more membranous as in apples and pears.
Thalamus: In the case of apples and pears, the thalamus is the part of the flower that develops into the fruit. These fruits are known as pome fruits, where the edible part is derived from the enlarged and fleshy thalamus. The true fruit part (which includes the pericarp: epicarp, mesocarp, and endocarp) is actually the central core that surrounds the seeds.

Key Points

• Cells of this tissue are living and show angular wall thickening. They also provide mechanical support, this tissue is collenchyma.
• Collenchyma is a simple permanent tissue.
• It allows the bending of various parts of a plant like tendrils and stems of climbers without breaking.
• This tissue is found in leaf stalks below the epidermis.
• There is very little intercellular space among the cells.

Additional Information

• Xylem-
  • ​It is a vascular tissue.
  • It transports water and minerals to the leaves that are absorbed by the roots.
  • Xylem consists of tracheids, vessels, xylem
    parenchyma, and xylem fibres.
• Sclerenchyma-
  • ​They are long and narrow as the walls are thickened
    due to lignin.
  • The cells of this tissue are dead.
  • This tissue is present in stems, around vascular bundles, in the veins of leaves, and in the hard covering of seeds and nuts.
• Epidermis-
  • ​The epidermis is the outermost layer of the primary plant body.
  • It is made up of elongated, compactly arranged cells, which form a continuous, single layer.

Hence, the correct option is (3) Collenchyma.

Key Points

• Vessel and tracheids are one of the components of the xylem tissue.
• The xylem is a complex vascular tissue.
• Xylem transports water and minerals to the leaves that are absorbed by the roots.
• The other two components of xylem are xylem
  parenchyma and xylem fibres.
• Tracheids and vessels are tubular structures and have thick walls, and many are dead cells when mature.
• This allows them to transport water and minerals vertically.

Explanation:

• Gymnosperms lack xylem vessels, it is a significant character of angiosperms.
• Pine is a gymnosperm and does not contain xylem vessels.
• However, teak, mango, and palm belong to Angiosperm. So that, they have vessels.

Hence, the correct option is (3) Pine.

The correct answer is a type of epidermal tissue.

Key Points

• Stomatal guard cells are a type of epidermal tissue.
• The epidermal tissue system forms the outermost covering of the whole body plant.
• In the epidermal tissue system, the epidermis is the outermost layer of the main plant body.
• This layer is interrupted by stomata.
• The stomata are openings in the epidermis of most of the aerial parts of the plants, especially in the leaves.
• Each stomata is composed of two bean-shaped cells called guard cells, which enclose the stomatal pore.
• The stomatal guard cells are generally much smaller in size as compared to other epidermal cells.
• Stomatal guard cells help to regulate the rate of transpiration during photosynthesis by opening and closing the stomata. 

Key Points

• Casparian strips are located on the roots of the endodermis of vascular plants.
• It is a band of cell wall material deposited on the radial as well as tangential walls of the endodermis.
• The endodermis is the innermost layer of the cortex. It is made up of parenchymatous cells.

Explanation:

• Casparian strips are made of suberin.
• Suberin is a water-impermeable and waxy material.
• It is a lipophilic, hydrophobic polyester biopolymer.
• It blocks the passive flow of water and solutes into the stele of a plant.
• Suberin prevents water from entering the pericycle.
• Thus, Casparian strips help in producing root pressure.

Additional Information

• Chitin - is the N-acetylglucosamine polymer found in the cell wall of fungi and exoskeletons of Arthropods.
• Cellulose - is a polysaccharide and a structural component of the primary cell wall of plants.
• Pectin - is a heteropolysaccharide present in the primary cell wall and middle lamella of plants.

Hence, the correct option is (4) Suberin.

The correct answer is  Phloem parenchyma

Concept:

• Monocotyledonous and dicotyledonous plants have different anatomical structures, which can be used to distinguish between the two.
• Monocots have a single cotyledon (seed leaf) in their seeds, while dicots have two cotyledons.
• The vascular bundles in monocot stems are scattered throughout the stem, whereas in dicot stems, they are arranged in a concentric ring.
• Monocots usually lack secondary growth due to the absence of a vascular cambium, whereas dicots often show secondary growth due to the presence of vascular cambium, which leads to the formation of wood and bark.
• Monocotyledonous plants generally have linear leaves with parallel venation, while dicotyledonous plants have broad leaves with reticulate venation.
• The roots of monocots are typically fibrous with numerous adventitious roots, whereas dicots usually have a main taproot with smaller secondary roots.

Explanation:

• Pith: Both monocot and dicot stems can have a pith, though its prominence varies and is often more noticeable in dicots.
• Hypodermis: Both types of stems can contain a hypodermis, which is a layer of cells beneath the epidermis.
• Phloem parenchyma: This tissue is typically absent in monocot stems but is present in dicot stems. The phloem parenchyma cells are part of the phloem tissue and play a role in the storage and lateral transport of nutrients.
• Vascular bundles: Both monocots and dicots have vascular bundles, but their arrangement differs; thus, vascular bundles cannot be the distinguishing characteristic here.

Concept:

• Roots are the parts of the plant that are normally underground.
• They carry out several important functions like the absorption of water and minerals from the soil.
• Anchorage to the plant is also provided by the roots.
• The absorption of water and minerals majorly takes place in the terminal portion of the root called the root tip.

Morphologically a root tip consists of the following four regions:

• Root cap
• Meristematic region or zone of active cell division
• Zone of elongation
• Zone of maturation

Explanation:

ANATOMY OF ROOT:

• ​The transverse section of a monocot/dicot root shows the following structures:

Epiblema: 

• It is the outermost single layer of cells without the cuticle.
• Some of its cells are prolonged into unicellular root hair.
• It is located in the root hair region of the root of a plant.

Cortex:

• After the epiblema, comes to lie the next layer called the cortex.
• It consists of several layers of parenchymatous cells.
• It functions as a storage for reserved food.

Exodermis:

• In a few dicots, after the death of epiblema, the outer layer of the cortex becomes cutinized and forms the exodermis.

Endodermis:

• It is the innermost layer of the cortex.
• The cells of the endodermis are barrel-shaped.
• The radial walls of the endodermis bear the Casparian strip or Casparian band.

Casparian strips:

• These are secondary thickenings of the endodermal cells.
• Its major component is suberin.
• Because of the presence of suberin in the Casparian strips, the passive flow of water and solutes is prevented from the strip to the stele.

Passage cells:

• Endodermis also shows the presence of passage cells.
• Passage cells are thin-walled unsuberized cells that are found next to the protoxylem.
• Passage cells provide pathways for the transport of nutrients like calcium and magnesium.

Pericycle:

• It is a single layer of parenchymatous cells that lie just below the endodermis.
• It bounds the stele or vascular cylinder.

Stele:

• It is the central region of the root.
• Xylem and phloem develop in this region of the root.

So the correct answer is option 1(Endodermis of roots facilitating rapid transport of water from cortex to pericycle).

Additional Information

• Suberin is a complex biopolymer made up of long-chain fatty acids - suberin acid - and glycerol. It is lipophilic.