Gymnosperms (General) Questions in English

(D) The term $Gymnosperm$ is derived from two Greek words: $gymnos$ meaning 'naked' and $sperma$ meaning 'seed'.
In these plants,the ovules are not enclosed by any ovary wall and remain exposed both before and after fertilization.
Therefore,the seeds that develop post-fertilization are not covered,i.e.,they are naked.
Thus,plants with naked seeds are classified as $Gymnosperms$.

(D) The plant body of $Bryophytes$ is thalloid and lacks true roots, stems, or leaves. $Thallophytes$ (like algae) have a simple, undifferentiated body. $Lichens$ are a symbiotic association between algae and fungi and do not possess true roots, stems, or leaves. $Gymnosperms$ are vascular plants where the main plant body is a $sporophyte$ that is well-differentiated into true roots, stems, and leaves.

(B) The smallest known gymnosperm is $Zamia \text{ } pygmaea$.
$Sequoia$ is known as one of the tallest gymnosperms (giant redwood).
$Thuja$ and $Bennettites$ are not considered the smallest.
Therefore, the correct option is $B$.

(D) $Gymnosperms$ are plants in which the ovules are not enclosed by any ovary wall and remain exposed both before and after fertilization. Many $Gymnosperms$ are adapted to survive in harsh environmental conditions. They are typically found in regions with low water availability,such as cold or dry climates. Therefore,they exhibit $Xerophytic$ characteristics,such as needle-like leaves,thick cuticles,and sunken stomata,to reduce water loss through transpiration.

(D) In the plant kingdom,the life cycle involves an alternation of generations between a haploid gametophytic phase and a diploid sporophytic phase.
In lower plants like algae $(Volvox)$ and bryophytes $(Anthoceros)$,the gametophytic phase is dominant and independent.
In pteridophytes,gymnosperms,and angiosperms,the sporophytic phase is dominant.
$Araucaria$ is a gymnosperm,which is a vascular plant where the sporophyte is the main,independent,and long-lived plant body.

(C) The tallest known tree species is the Coast Redwood,scientifically known as $Sequoia \ sempervirens$.
These trees are gymnosperms and are found in the coastal regions of California.
Their height can reach up to approximately $115-120 \ m$.
Among the given options,$120 \ m$ is the most accurate representation of the height of the tallest trees.

(D) The plants in which the ovules are not enclosed by any ovary wall and remain exposed,both before and after fertilization,are called Gymnosperms. The term 'Gymnosperm' is derived from the Greek words 'gymnos' (naked) and 'sperma' (seed). In these plants,the seeds are not enclosed within a fruit. Therefore,the correct option is $D$.

(A) The tallest tree species is $Sequoia$ $sempervirens$,commonly known as the coast redwood.
It belongs to the group of gymnosperms.
These trees can reach heights of over $115 \ m$.
Therefore,the correct option is $A$.

(C) In $Gymnosperms$,the male and female cones are produced on the same or different trees. The microspores develop into male gametophytes which are highly reduced and confined to only a limited number of cells. The pollen grains are released from the microsporangia and are carried by air currents (wind). This process of pollination is known as $Anemophily$. Therefore,pollination in $Gymnosperms$ occurs by wind.

(C) The smallest known gymnosperm is $Zamia \, pygmaea$.
$Wolffia \, globosa$ is the smallest known angiosperm.
$Datura \, festuosa$ and $Rosa \, indica$ are also angiosperms.
Therefore, the correct option is $C$.

(B) The term $Gymnosperm$ is derived from two Greek words: $Gymnos$ meaning 'naked' and $Sperma$ meaning 'seed'.
In gymnosperms,the ovules are not enclosed by any ovary wall and remain exposed both before and after fertilization.
Therefore,they are referred to as plants with 'naked seeds'.

(C) Plants that produce seeds but do not produce fruits are known as gymnosperms.
Gymnosperms are naked-seeded plants where the ovules are not enclosed by any ovary wall and remain exposed both before and after fertilization.
Among the given options,$Selaginella$ and $Equisetum$ are pteridophytes (seedless vascular plants),and $Dryopteris$ is a fern.
$Ginkgo$ is a gymnosperm,which produces seeds but lacks fruits because it lacks an ovary.

(C) The plant kingdom is classified based on the presence or absence of seeds and flowers.
$1$. $Fungi$ are not plants.
$2$. $Bryophytes$ and $Pteridophytes$ are cryptogams, meaning they do not produce seeds.
$3$. $Gymnosperms$ are seed-bearing plants, but they do not produce flowers or fruits; their seeds are naked (exposed).
$4$. $Angiosperms$ are flowering plants that produce seeds enclosed within fruits.
Therefore, the correct group that produces seeds but is non-flowering is $Gymnosperms$.

(D) The correct answer is $D$.
$1$. Molds are fungi,and their cell walls are composed of chitin.
$2$. Protozoa are animal-like protists and generally lack a cell wall.
$3$. Blue-green algae (Cyanobacteria) have cell walls made of peptidoglycan.
$4$. Conifers are gymnosperms (plants),and their cell walls are primarily composed of cellulose.

(C) $Araucaria$ is a genus of evergreen coniferous trees in the family $Araucariaceae$.
Statement $A$ is true: The scale leaves of $Araucaria$ are indeed small,brown,and often appressed to the stem.
Statement $R$ is false: $Araucaria$ is a gymnosperm. In gymnosperms,the sporophytic phase is dominant,long-lived,and independent. The gametophytic phase is highly reduced,dependent on the sporophyte,and is not subterranean. The description of a long-lived,subterranean gametophyte is characteristic of certain pteridophytes (like $Lycopodium$),not gymnosperms like $Araucaria$.

(A) In gymnosperms,the ovules are not enclosed by any ovary wall and remain exposed both before and after fertilization.
Since the fruit is a ripened ovary,the absence of an ovary in gymnosperms means they cannot produce true fruits.
Therefore,both the assertion $(A)$ and the reason $(R)$ are correct,and $R$ is the correct explanation for $A$.

(A) Gymnosperms are plants in which the ovules are not enclosed by any ovary wall and remain exposed,both before and after fertilization. The seeds that develop post-fertilization are not covered,i.e.,are naked. $Pinus$ is a classic example of a gymnosperm. Since $Pinus$ belongs to the group of gymnosperms because its ovules are naked (not enclosed by an ovary),statement $R$ provides the correct scientific reason for statement $A$.

(C) $Thuja$ is a genus of coniferous trees in the family $Cupressaceae$,which belongs to the group Gymnosperms.
In Gymnosperms,the endosperm is a haploid tissue formed before fertilization by the process of megasporogenesis and gametophyte development.
In contrast,the endosperm in Angiosperms is triploid $(3n)$ and is formed after fertilization through the process of double fertilization (fusion of one male gamete with two polar nuclei).
Therefore,the statement $S$ is true,but the statement $R$ is false.

(C) $S :$ $Sequoia$ $sempervirens$ (Redwood tree) is a gymnosperm,not an angiosperm. Therefore,statement $S$ is false.
$R :$ $Eucalyptus$ is indeed one of the tallest trees in the world,but it is an angiosperm. However,the statement $R$ is true in isolation.
Since $S$ is false and $R$ is true,the correct option is $C$ (Note: Based on standard biological classification,$S$ is false and $R$ is true).

(A) Gymnosperms are heterosporous,meaning they produce two types of spores: microspores and megaspores. Therefore,the statement 'Gymnosperms - Homosporous' is incorrect.
Microsporangia are structures that produce microspores,often associated with male cones (strobili) in gymnosperms.
Most gymnosperm ovules are orthotropous (straight).
Gymnosperms typically produce unisexual cones (male or female cones).

(C) Plants that produce seeds but lack flowers are known as $Gymnosperms$.
$1$. $Gymnosperms$ are seed-bearing vascular plants where the seeds are not enclosed within an ovary (naked seeds).
$2$. $Angiosperms$ are flowering plants where seeds are enclosed within fruits.
$3$. $Pteridophytes$ are seedless vascular plants.
$4$. $Fungi$ are heterotrophic organisms and do not produce seeds.
Therefore,the correct group is $Gymnosperms$.

(A) In $Gymnosperms$, the endosperm is a haploid $(n)$ tissue formed before fertilization as a result of the development of the female gametophyte. In contrast, in $Angiosperms$, the endosperm is typically triploid $(3n)$ and is formed after fertilization through the process of double fertilization (specifically, the fusion of one male gamete with two polar nuclei). Therefore, the formation of endosperm before fertilization is a characteristic feature that distinguishes $Gymnosperms$ from $Angiosperms$.

(A) In gymnosperms,the endosperm is formed before fertilization by the process of megasporogenesis and subsequent mitotic divisions of the functional megaspore. Since it is formed from the haploid megaspore,the endosperm of gymnosperms is haploid $(n)$.

(A) The tallest tree species known is $Sequoia$ $sempervirens$,commonly known as the coast redwood. It belongs to the group of gymnosperms. While $Eucalyptus$ is also a very tall tree,$Sequoia$ holds the record for the greatest height among living trees.

(B) living fossil is an extant taxon that closely resembles related species known only from the fossil record.
Among the given options,$Cycas$ is widely recognized as a living fossil because it has remained morphologically unchanged over millions of years and represents an ancient lineage of gymnosperms.

(C) In Gymnosperms like $Pinus$ and $Cycas$,the ovules are orthotropous and unitegmic. This means they are surrounded by a single integument. Therefore,the correct answer is $C$.

(D) Plants that produce seeds but do not produce flowers are known as gymnosperms.
Gymnosperms are naked-seeded plants where the ovules are not enclosed by any ovary wall and remain exposed both before and after fertilization.
Among the given options,$Pinus$ is a gymnosperm.
Maize,Mint,and Peepal are angiosperms,which are flowering plants that produce seeds enclosed within fruits.

(A) $Cycas$ belongs to the group Gymnosperms. The defining characteristic of Gymnosperms is that their ovules are not enclosed by any ovary wall and remain exposed,both before and after fertilization. In contrast,Angiosperms are characterized by seeds that develop inside fruits,which are formed from the ovary. Although $Cycas$ may show two cotyledons (a feature often associated with dicot angiosperms),the presence of naked ovules (gymnospermy) is the primary taxonomic criterion that excludes it from the Angiosperms.

(A) Turpentine is a fluid obtained by the distillation of resin harvested from living trees,mainly pines $(Pinus)$.
It is widely used as a solvent and in the production of various industrial products.
Therefore,the correct option is $A$.

(A) In $Gymnosperms$,the ovules are naked and not enclosed within an ovary wall.
Pollination in $Gymnosperms$ occurs primarily through the agency of wind,which is known as $Anemophily$.
The pollen grains are released from the microsporangia and are carried by air currents to reach the ovules directly.

(D) $Gymnosperms$ are plants in which the ovules are not enclosed by any ovary wall and remain exposed,both before and after fertilization. Since the fruit is a ripened ovary,the absence of an ovary in $Gymnosperms$ results in the absence of fruit formation. Therefore,the seeds are naked.

(B) living fossil is an extant taxon that closely resembles related species known only from the fossil record.
In the plant kingdom,$Cycas$ is widely recognized as a living fossil because it has remained morphologically unchanged for millions of years and represents an ancient lineage of gymnosperms.
$Spirogyra$ is an alga,mosses are bryophytes,and $Saccharomyces$ is a yeast (fungus),none of which are classified as living fossils.

(B) Conifers belong to the group $Gymnosperms$,while grasses belong to the group $Angiosperms$ (Monocots).
In $Gymnosperms$ (like conifers),the endosperm is formed before fertilization and is haploid $(n)$.
In $Angiosperms$ (like grasses),the endosperm is formed after fertilization through the process of double fertilization (triple fusion) and is triploid $(3n)$.
Therefore,the formation of endosperm before fertilization is a characteristic feature that distinguishes conifers from grasses.

(C) Gymnosperms are seed-bearing plants where the ovules are not enclosed by any ovary wall and remain exposed both before and after fertilization. In contrast,Pteridophytes are seedless vascular plants that reproduce via spores. The presence of ovules is a key evolutionary advancement in Gymnosperms that distinguishes them from Pteridophytes,which lack ovules and seeds.

(B) The term 'heterosporous' refers to the production of two different types of spores (microspores and megaspores).
Gymnosperms are heterosporous plants.
They produce megaspores which are retained within the megasporangia (ovules) on the megasporophylls,making them 'ovuliferous'.
Therefore,gymnosperms are characterized by being heterosporous and having ovuliferous structures.

(B) During the evolution of seed plants,a significant transition occurred from exospory (where spores germinate outside the sporangium) to endospory (where the gametophyte develops within the spore wall). This adaptation was crucial for the protection of the developing gametophyte from desiccation and environmental stress,ultimately leading to the evolution of the seed habit.

(B) Gymnosperms are plants that produce two types of spores,namely microspores and megaspores.
These spores are produced within microsporangia and megasporangia,respectively,which are borne on sporophylls arranged spirally along an axis to form lax or compact strobili or cones.
Because they produce two different types of spores,they are classified as heterosporous plants.

(B) monoecious plant is one that bears both male and female reproductive structures on the same individual plant.
$Pinus$ is a monoecious gymnosperm, meaning both male and female cones are produced on the same tree.
$Cycas$, $Date \text{ } palm$, and $Marchantia$ are dioecious, meaning they have separate male and female individuals.

(A) Gymnosperms are seed-bearing vascular plants in which the ovules are not enclosed in any ovary wall.
$1$. They include the largest trees,such as $Sequoia$ (redwood tree).
$2$. They possess the largest ovules among all plant groups (e.g.,$Cycas$).
$3$. They also produce the largest male gametes in the plant kingdom (e.g.,$Cycas$).
Therefore,the correct answer is Gymnosperms.

(A) In gymnosperms,the xylem tissue lacks vessels (tracheae). Therefore,the primary elements responsible for the conduction of water and minerals are the tracheids. Tracheids are elongated,tube-like cells with thick,lignified walls and tapering ends,which facilitate efficient water transport in the absence of vessels.

(A) $Cycas$ is a gymnosperm.
Gymnosperms are characterized by the presence of tracheids in their xylem,while vessels are typically absent (except in Gnetales).
Therefore,the statement that xylem contains vessels is incorrect for $Cycas$.
$Cycas$ does possess coralloid roots which contain nitrogen-fixing cyanobacteria ($Anabaena$ or $Nostoc$).
Male cones in $Cycas$ are well-developed and large.

(A) Gymnosperms are plants in which the ovules are not enclosed by any ovary wall and remain exposed,both before and after fertilization. Since the fruit is a ripened ovary,the absence of an ovary in gymnosperms means they cannot produce true fruits. Therefore,the correct option is $A$.

(A) In gymnosperms,pollination is exclusively anemophilous (wind-pollinated). The pollen grains are released from the male cones and are carried by wind currents. These pollen grains reach the ovules,which are exposed on the megasporophylls. The pollen grains enter the ovule through the micropyle,which is the opening of the ovule. Therefore,the correct description is anemophilous and micropylar.

(D) Gymnosperms are naked-seeded plants.
$1$. They lack vessels in their xylem (except in Gnetales).
$2$. They do not produce fruits because they lack an ovary,meaning the ovules are exposed.
$3$. They lack companion cells in their phloem (they have albuminous cells instead).
Therefore,all the given options are correct characteristics of gymnosperms.

(B) In the plant kingdom,$Cycas$ is a gymnosperm that produces the largest sperms (male gametes) among all living organisms. These sperms are multiciliated,large,and motile,which is a primitive characteristic retained by $Cycas$.

(C) In gymnosperms,the term 'gymnos' means naked and 'sperma' means seed.
These plants are characterized by having ovules that are not enclosed by any ovary wall.
In angiosperms,the ovules are enclosed within the ovary,which develops into the fruit after fertilization.
Since gymnosperms lack a true ovary (and thus lack a fruit),the ovules remain exposed or 'naked' both before and after fertilization.

(B) In $Cycas$,certain specialized roots are called $Coralloid$ $roots$.
These roots are associated with nitrogen-fixing cyanobacteria,specifically $Anabaena$ and $Nostoc$.
These roots are typically branched and grow in a coral-like pattern,which is why they are named $Coralloid$ $roots$.

(A) In $Gymnosperms$,the endosperm is formed before fertilization by the fusion of megaspores and is haploid $(n)$ in nature. It represents the female gametophytic tissue. In contrast,the endosperm in $Angiosperms$ is formed after fertilization through double fertilization (triple fusion) and is triploid $(3n)$.

(C) In gymnosperms,the plant body is diploid $(2n)$.
$1$. The root is a vegetative part of the plant body,so its cells are diploid $(2n)$. Given the haploid number $(n)$ is $12$,the number of chromosomes in the root is $2 \times 12 = 24$.
$2$. The endosperm in gymnosperms is a haploid $(n)$ tissue formed before fertilization. Therefore,the number of chromosomes in the endosperm is $12$.
Thus,the number of chromosomes in the root and endosperm is $24$ and $12$,respectively.

(D) Gymnosperms are plants in which the ovules are not enclosed by any ovary wall and remain exposed both before and after fertilization.
They include medium-sized trees,tall trees,and shrubs.
For example,$Sequoia$ is one of the tallest tree species known.
Therefore,all the given options are correct.