reproduction (image)

In case of sponges, the parent releases a specialised mass of cells enclosed in a common opaque envelope, called as the gemmule. Gemmules are thought to be internal buds, which on germination give rise to an offsprin..

A sperm is a haploid male gamete which fuses with the ovum to form the diploid zygot..

In this phase, chromosomes move to the equator of the cell. Pairs of chromatids become attached to the spindle fibres at their centromeres fig. 17.3 - Stages of Mito..

Leaves are not a common means of vegetative propagation in nature. But, in species of Bryophyllum, plantlets are produced from the notches of the margin of intact leaves, while the latter are still attached to the parent plant. In other species of Bryophyllum, the leaves must be detached or injured..

It is the transference of the pollen grains from the anther of one flower to the stigma of another flower borne on a different plant of the same species. It is also known as allogamy or xenogamy. Cross pollination requires the help of abiotic or biotic agencies such as wind, water, insects, birds, ..

is the male reproductive part of the flower. The individual units of androecium are called the stamens . Each stamen has a thread-like filament at the free end of which is attached the four-lobed anther . The anther has four pollen-sacs, one in each lobe. The pollen-sacs contain c..

It is generally seen in bacteria and most fungi. One of the cells enlarges and forms the sporangium (literally meaning spore sac). The nucleus divides many times and then the daughter nuclei are surrounded with protoplasm bits to form daughter cells called spores. The spores are covered with a thi..

Menstruation and Menstrual Cycle - At about the age of 10 to 13 years, the ovaries of females are stimulated by the follicle stimulating hormone (FSH) of the pituitary. This is called the onset of puberty and is accompanied by release of hormones oestrogen and progesterone. These hormones control t..

is the male reproductive part of the flower. The individual units of androecium are called the stamens . Each stamen has a thread-like filament at the free end of which is attached the four-lobed anther . Structure of Anther The anther has four pollen-sacs, one in each lobe. The p..

It is a variation of the grafting method explained above. In this method, the scion is a bud along with some bark. A 'T'-shaped cut is made on the stock into which the scion is inserted and bound with a tape...