Test: Reproduction in Organisms - 4 (Old NCERT) - Grade 12 MCQ

Tubers are the underground modification of stem consisting of axillary buds on its surface, and this axillary bud is meristematic, which helps in the growth of new plants. Tubers stores starch. The buds are also known as eye or scales and the buds sprout and develop into a new plant. Potato tubers need frequent irrigation, i.e., the process where a controlled amount of water is supplied to the plants at needed intervals. The first irrigation should be given immediately after sowing and after that at one-week intervals. After the formation of tubers, the frequency of irrigation decreases.

If we look at options now:

• Option A is Branches. This option is incorrect as the axillary bud is responsible for forming a new plant, not branches. Therefore, this option gets eliminated.
• Option B is Stored food. This option is incorrect as the axillary bud is responsible for forming a new plant not stored food. Therefore, this option gets eliminated.
• Option C is Roots. This option is incorrect as the axillary bud is responsible for forming a new plant, not Roots. Therefore, this option gets eliminated.
• Option D is the Scales/Eyes. This option is correct since the axillary bud is responsible for forming new plants and the bud is also known as scales/eyes due to which this option is right and these buds sprout, then develop into a new plant.

Oogamous reproduction involves fusion of one motile male gamete and another non-motile large sized female gametes.

Fusion of similar gametes is known as isogamous reproduction. Fusion of dissimilar motile or non-motile gametes is known as anisogamous reproduction.

So, the correct option is 'Motile and non-motile gametes'.

Oogamy is a form of sexual reproduction. It is a form of anisogamy (heterogamy) in which the female gamete is significantly larger than the male gamete and is non-motile.The male gametes are smaller in size and motile So, the correct option is 'Large non-motile female gamete and small motile male gamete'.

Members of the genus Hydra reproducing by budding, a type of asexual reproduction in which a new individual develops from a generative location on the parent's body.

Estrogen secreted from ovarian follicles under the influence of FSH causes the proliferation of the endometrium of the uterine wall.

Multiplication of genetically identical copies of a cultivar by asexual reproduction is called clonal propagation and a plant population derived from a single individual by asexual reproduction constitutes a clone.

• Amoeba is a unicellular organism with a unique ability to change its regular shape by extending and retracting its pseudopodia (false-feet) which is an arm-like or finger-like projection. It does not possess a cell wall that allows it to move freely. It mainly reproduces by Binary fission which is an asexual mode of reproduction. Amoeba eats by stretching its pseudopodia around the food and pulls it inside the rest of the body.
• This process begins when the parent cell pulls its pseudopodia inside to reach a spherical shape.
• After mitotic cell division, the nucleus and cytoplasm get constricted.
• The cytoplasm starts dividing and results in the formation of two daughter cells.

Birds are oviparous as they lay eggs.

Penicillium is a large and difficult genus encountered almost everywhere, and usually the most abundant genus of fungi in soils. Some species of Penicillium reproduce sexually by means of asci and ascospores produced within small stony stromata.

Binary fission is the type of asexual reproduction in which the parent cell divides into two daughter individuals or daughter cells. In binary fission, the fully grown parent cell first gets organized into two halves. After replication of its genetic material, the parent cell divides into two equal-sized daughter cells. The genetic material is replicated, then equally split. Binary fission is common among prokaryotes, e.g. archaea, eubacteria, cyanobacteria, and certain protozoans. At first, the circular DNA and plasmids replicate. Then the cell gets bigger and the circular DNA strands move to the opposite poles of the cell. Soon, the cytoplasm begins to divide and new cell walls begin to form. Then the cytoplasm divides and two new daughter cells are produced.
 

Gametes are a mature sperm (from a male) and a mature egg, or oocyte (from female). Each gamete is haploid (n), that is half the number of DNA required for the growth and development of an organism. Fusion of these two gametes results in a diploid cell (2n) with the right amount of DNA required. A fertilized egg is known as zygote which can develop to form an embryo.

Vallisneria is a submerged hydrophyte. It is a dioecious plant with the flowers borne under water. The male flowers detach on maturity and float on the surface of the water while the female flowers grow under water and they come up to the surface with the help of their thin long stalk. As the stalk grows further, the flowers which were vertical become horizontal and thus, a cup like depression is formed around the female flower. The male flowers which are floating on the surface of the water, fall into the cup and due to jerk, the anthers dehisce and pollen is transferred to the stigma and thus, pollination occurs on the surface of the water. This kind of pollination found in Vallisneria is called ephydrophily. 

Amphibious are the animals that can live on water as well as on land. Oviparous are the animals that lay eggs. Triploblastic describes the animal having a body composed of three embryonic cell layers as the ectoderm, mesoderm, and endoderm. Viviparous are animals that give birth to live young one that has developed inside the body of the parent.

Tissue culture involves the culture of totipotent cells in nutrient media under sterile conditions. The mass of the totipotent cell is known as a callus. It is unorganized actively dividing the mass of cells maintained in culture. It has the meristematic cell which has an ample amount of cytoplasm to trigger cell division. It is treated with growth hormones to allow cell division and differentiation. Callus when treated with nutrient media with a high percentage of auxin it promotes rooting and when it is treated with media with a high percentage of cytokinin it stimulates cell maturation, differentiation and finally, promotes the development of stem.

The yolk is a part of an egg, that feeds the developing embryo in animals. It is composed of carbohydrates (3.5%), protein (16%) and fats (phospholipids 26.5%) of total yolk. The main fatty acids present in the yolk are oleic acid, linoleic acid, palmitic acid etc.

Scion is the part of the grafted plant that gives rise to the plant shoot that will, later on, produce all of the plant parts such as leaves, stems, flowers, and fruits. Everything above the scion is cut off in the spring hence all nutrients and water absorbed by the roots becomes available to the growing scion.

A gemma (plural gemmae) is a single cell, or a mass of cells, or a modified bud of tissue, that detaches from the parent and develops into a new individual. This type of asexual reproduction is referred to as fragmentation. It is a means of asexual propagation in plants.

Reproduction in Bryophyllum occurs asexually through vegetative propagation by leaves. These buds can give rise to new plants with adventitious roots, shoots, and small leaves. The new plants then detach from the leaves and develop into a mature plant after coming in contact with the soil.

Bulbs are modified stems of some plants. The stem is modified to be a storage organ where the plant stores its reserve materials which it would use in times of need. The best example of this would be an onion.

Apomixis is the term given to any phenomenon that leads to formation of embryos wherein parts of the sexual apparatus are used, but without fertilisation. Fertilisation is also absent in vegetative propagation, but parts of sexual apparatus are not involved. An example of apomixis is Citrus.