Tag: introduction to reproduction

Rhizomes (eg., Ginger), tubers (eg., Potato) and corms (eg., Colocasia) are underground storage stems which can be used for vegetative propagation.  Prefix "Allo" means different hence transfer of pollen from one flower to stigma of another flower is called allogamy. It is compulsory in unisexual flower but may also occur in bisexual flowers.

Apomixis is a process of asexual method of seed formation in which embryo develops from maternal tissues of the ovule without the processes of meiosis and gametogenesis. It is seen in higher plants. It conserves the genetic structure of plants. Heterosis can be maintained permanently in crop plants by this process. 

Intersex is referred to as the variation in sex characteristics that does not allow the individual to be distinctly called as male or female.
Hermaphrodite is an organism who has both male and female sex organs (not necessarily characteristics).
Bisexual means hermaphrodite.
If an individual exhibits both male and female secondary sexual characteristics is called as gynandromorph.
So, the correct answer is option D.

The different yolk's protein has distinct roles. Phosvitins are important in sequestering calcium, iron and other cations for the developing embryo. Phosvitins are one of the most phosphorylated (10%) proteins in nature, the high concentration of phosphate groups providing efficient metal-binding sites in clusters. Lipovitellins are involved in lipid and metal storage, and contain a heterogeneous mixture of about 16%  noncovalently bound lipid, most being phospholipid. Lipovitellin-1 contains two chains, LV1N and LV1C. Hence, option C is correct.

Earthworms are hermaphrodite animals, meaning that both testes and ovary are present in a single body but cross-fertilisation is the rule. At the time of reproduction two worms come to lie close to each other and exchange sperms. The sperms are stored in pouches called spermatheca. So, the correct answer is option C.

Metamorphosis is the process of development of organisms after hatching or birth. Insects that go through three stages of change in their life cycle have an incomplete metamorphosis. The first stage is the egg. During this time, the insect will hatch into a form, called a nymph. The nymph is basically a small version of the adult insect. Once a nymph outgrows its exoskeleton it will go through a process called moulting which is to leave the old skin or exoskeleton behind. The new skin will harden and become the new exoskeleton. This will happen many times until the insect finally becomes an adult. So, the correct answer is option B.

Lippes loop is a type of intrauterine contraceptive device made of inert plastic in a double S-shape, which can be inserted through the cervix into a cannula and takes a trapezoidal shape within the uterus. The Lippies Loop was made up of polyethylene and impregnated with radium phosphate for radiopacity. It was used worldwide but in many countries including India as well, it is being replaced with Copper T. It was manufactured in Kanpur. Hence, option D is the correct answer.

Parthenogenesis is a type of asexual reproduction in which the embryo grows and develops from egg without fertilization. Apogamy is a type of reproduction in which sporophyte develops from a gametophyte without fertilization. Parthenocarpy is the phenomenon of development of fruit without fertilization. In this, fruits are seedless. Pseudogamy is a form of reproduction in which the embryo develops from egg following the stimulus of pollination but without fertilization. It involves activation of egg by sperm but does not involve nuclear fusion. 

Binary fission is the asexual form of reproduction in which single-celled organism divides itself into two cells, in favourable condition.
Multiple fission is the asexual form of reproduction where the parent amoeba cell divides to give many daughter cells in unfavourable condition.
Thus, the correct answer is option B.