Histology MCQ : Introduction and Explanation

Answer. (C) Cucurbitaceae

Explanation- Herbaceous climbing and trailing plants make up the Cucurbitaceae family. Herbs are either annual or perennial. Bicollateral vascular bundles are those that have phloem on both sides of the xylem. In this type of stem bundle, phloem is found above (external to) the metaxylem and below (internal to) the protoxylem elements. Plants in the Cucurbitaceae, Solanaceae and other families have this type of vascular bundle. Plants in the Malvaceae and Poaceae families have lateral vascular bundles. Liliaceae plants have concentrated amphivasal vascular bundles.

Answer. (B) Because they Lack Cambium

Explanation: Because monocot plants lack the cambium tissue seen in dicot plants, they cannot be grafted. Cambium tissue is a type of meristematic tissue found in dicot plants' vascular bundles. This tissue has a regeneration capacity, which means it can regenerate new tissue during grafting. Grafting is impossible in monocots due to the lack of cambium. It is only effective with dicots and gymnosperms, not monocots. Monocots cannot graft because they lack cambium, not because they have scattered vascular bundles, parallel venation, or are herbaceous.

Answer- (A)  Lateral meristem

Explanation- The lateral meristems, also known as secondary meristems, are made up of the vascular and cork cambium in all woody plants. They allow the plant to develop in girth, increasing its size. Secondary growth is the term for this sort of growth in vascular plants. 

Answer- (D) Callus Deposition

Explanation: Callus is a thickened mass that develops at the base of a cut or surrounding a wound. Parenchyma tissue (callus) fills the area created when a section of the plant is taken away or eliminated. The cambium cells are the ones who make the parenchyma.

Answer. (A) Endodermis

Explanation. Casparian strip is a band of cell wall material that is chemically distinct from the rest of the cell wall and is deposited on the radial and transverse walls of the endodermis. The Casparian strip is made of suberin and sometimes lignin, whereas the cell wall is made of lignin and lacks suberin. It prevents the passive flow of materials into a plant's stele, such as water and solutes.

Answer- (C) Companion cells regulate the activity of non-nucleated sieve tube cells.

Explanation- Sieve tube elements are a type of phloem component that helps carry food from leaves to other plant tissues. These are long, slender tube-like structures with perforated sieve plates organised in a longitudinal sequence. Sieve plates serve as a link between them. These are live cells that do not lignify and lose their nucleus as they mature.

Answer- (C) Tracheids and vessels

Explanation- Tracheids are elongated cells in vascular plants that transport water and mineral salts through the Xylem. One of two types of tracheary elements is tracheids. The other category is vessel components. Tracheids, unlike vessel components, do not have perforated plates. Tracheids' maximum capacity is theoretically limited due to their single-celled nature.

Answer- (B) Pinus

Explanation- Vessels have circular cells in their cross-section. End walls with perforations are present. They can only be found in angiosperms (flowering plants). While Pine is a Gymnosperm (a non-flowering plant), Gymnosperms lack vessels and instead have Tracheids in place of vessels.

Answer- (D) All of the above

Explanation- Food supplies are transported via phloem from leaves to other sections of the plant. Sieve tube elements, companion cells, phloem parenchyma, and phloem fibres make up phloem. Sclerenchymatous cells make up phloem fibres (bast fibres). Commercially, jute, flax, and hemp phloem fibres are used they a classified as a bast fibre.

Answer- (D) Their sporophyte is attached to the gametophyte

Explanation- The gametophyte is the Bryophyte's leafy thallus, which is a haploid and produces gametes by mitosis. The spermatozoids are biflagellate that swim through a thin layer of wetness on the surface of the thallus to reach the eggs, which are kept inside but exposed to the outside via pores. The spermatozoids are drawn to the egg's chemicals, and only one can fertilise each egg. A diploid zygote is produced as a result of fertilisation, which matures into a diploid plant that produces spores via meiosis and is known as a sporophyte. The sporophyte remains attached to the parent gametophyte and is referred regarded as 'parasitic' on it since it lacks chlorophyll and relies on the gametophyte for much of its sustenance.

Answer. (C) Spore mother cell

Explanation- Within the sporogonium, spore mother cells are formed. The sporophyte generation ends with these diploid (2n) sporophytes. Tetrads of haploid (n) spores are created when the spore mother cells undergo reduction division (meiosis). The gametophyte generation starts with the spores.

Answer- (A) Sphagnum

Explanation- Sphagnum, which is found in bogs, can absorb up to 18 times its weight in water. Gardeners use it to keep seedlings and cut plant parts moist during transport and propagation. It was also utilised as a substitute for absorbent cotton in the past.

Answer- (A) 2 - Flagella

Explanation- Antheridia are the male sex organs found in bryophytes. They are carried by multicellular stalks that are small in length. Each antheridium has a stalk and a body that may be distinguished. The antheridial body is made up of a mass of androgenic cells encased in a sterile jacket that is one cell thick. Androcytes, or antherozoid mother cells, are produced by these androgenic cells. Antherozoids are produced by androcytes. Bi flagellate formations with a long coiled body are known as antherozoids or spermatozoids. For fertilisation, the antherozoids are transported to archegonia via water.

Answer. (D) All of the Above

Explanation- Bryophytes are mosses and liverworts grouped together. The body of the plant is thalloid, with no true vascular tissues and a number of other primitive characteristics. They don't have genuine stems, roots, or leaves, but they do have cells that execute these roles in general. Because bryophytes have chloroplasts, they are autotrophic. The gametophyte, which is the prominent stage in all Bryophytes, is the lush green plant. The sporophytes do not have the ability to live on their own. They emerge from the archegonia's fertilised egg and are completely reliant on the parent gametophyte for nourishment.

Answer- (D) Liverworts and moss

Explanation- Bryophyta are tiny, nonvascular plants that have been around for over 500 million years. Bryophytes were most likely the first terrestrial plants. The gametophyte phase dominates the life cycle of bryophytes, which lack vascular tissue. The plants' size is limited by the lack of conducting cells, which keeps them under 5 inches tall. Bryophytes don't have roots; instead, they have rhizoids, which are root-like structures. Hornworts, liverworts, and mosses are examples of bryophytes.

Answer. (B) Bryophyta

Explanation- Vascular plants include pteridophytes and spermatophytes. Thallophytes with generational alternation have separate gametophytes and sporophytes. Bryophytes are nonvascular plants having a less developed sporophyte that relies on gametophytic generation for reproduction. 

Answer- (A) Mosses

Explanation- Hepaticae (Liverworts), Anthocerotae (Hornworts), and Musci are the three classes of Bryophytes (Mosses). Mosses feature upright radially symmetrical leaves plant bodies that are generated from protonema, a filamentous or thalloid juvenile stage. The sporophyte is partially dependent on the gametophyte and has a lot of green tissue. Funaria (cord moss), Sphagnum (bog or peat moss), Polytrichum, and other mosses are examples.

Answer. (C) Bryopsida

Explanation- Bryophytes do not have genuine leaves, stems, or roots, but they do have a comparable structure. They have rhizoid-like hair that anchors them to the ground. Thallus takes water and minerals directly from the ground or the atmosphere in the lack of roots. As a result, they can only survive in damp environments. Bryopsida is the correct choice from the list above. Bryophytes belonging to the Hepatocopsida family have a dorsoventrally flattened lobed plant body with unicellular rhizoids. The other two classes belong to the Pteridophyta division.

Answer. (D) Anthoceros

Explanation- Anthocerotae is a Bryophyta class. They have a thallus plant body with unicellular rhizoids that are dorsiventral. The sporophyte is a horn-shaped sporophyte with a lot of green tissues that is largely reliant on the gametophyte. Archegonia are present in Anthoceros and are sunken in the thallus. The archegonium is not covered by jacket cells. The archegonium is protected by the thallus's vegetative cells. Cover cells, also known as lid cells, are situated at the archegonia's tip.