In diploid organism, gametes are produced by meiosis division but in haploid organism gametes are produced by:
During mitosis division two daughter cells are produced having same number of chromosome. In meiosis division four daughter cells having half the number of chromosomes are produced. So, haploid organisms follow mitosis division.
Apomixis is modified form of reproduction in plants in which seeds are formed without fusion of gametes. The diploid cell of nucellus develops into an embryo giving a diploid seeds.
Development of fruit without fertilization is called?
Which plant can propagated Vegetatively by leaf?
Bryophyllum plants grow in marshy areas where seeds are not able to germinate. The leaf margin of Bryophyllum contains numerous plantlets before falling on muddy land.
The degenerative and irreversible changes in the organism is known as_______.
Life cycle of organism’s starts from growth and development followed by reproductive phase. After that senescence phase starts in which degenerative changes starts which is generally irreversible and leads to death of organisms.
Which of the following is developed by parthenogenesis:
Since drones are developed without fertilization of egg, they are developed by parthenogenesis. Queen and worker honey bees are developed by fertilization of egg.
Senescence in most of the animals is NOT caused by _____.
Senescence is a natural process followed by maturity of organism. The metabolic processes of organisms start slowing down in this process leading to wear and tear of vital body organ. Nutrition does not affect the process of senescence.
What is the period from birth to natural death of an organism known as?
The period from birth to natural death of an organism is known as its life span. It varies from few years to thousand years, depending on the organism.
Which of the following is NOT correct about artificial means of vegetative propagation?
During vegetative propagation, new organisms are formed by single plant parts. So, new individuals are genetically similar to each other and there is no genetic variation.
Identify the organism and type of reproduction in figure below.
Asexual mode of reproduction in yeast takes place by budding process in which small outgrowth develops on tips followed by karyokinesis. Same process is repeated several times to form chain of yeast cells.
A flower having both male and female reproductive parts are termed as______.
The male and female reproductive parts of flower are stamen and carpel. If both stamen and pistil are present in same flower, the flower is called monoecious.
Menstrual cycle, in human female is completed in ___.
The menstrual cycle in human being is repeated at the interval of 28/29 days. It starts with raptures of inner lining of uterus. In the middle of menstrual cycle ovulation takes place.
The chances of survival of young one is greater in ___________ organism.
In Viviparous, well developed young one is produced by female at the end of gestation period. There is no fear of predator of outer environment as in case of oviparous in which young one comes out of egg. Viviparous mode of development is not influenced by adverse environmental conditions.
The female gametophyte in angiosperm is also known as _______.
In angiosperms, female gametophyte is called embryo sac which is 7-celled but 8-nucleated structure. Embryo sac is formed inside the ovary that changes into seeds after fertilisation.
The process in which mature differentiated cells reverse to meristematic activity to form callus is called as?
Meristematic tissue change into permanent tissue by the process of differentiation. The permanent tissue becomes meristematic due to de-differentiation.
In non-primate mammals like cow, sheep, rats, dogs etc., such cyclical changes during reproduction are called?
Sexual reproduction in mammals involves cyclic changes during which ovum is released. In primitive animals it is called oestrus cycle and in in primates including human being it is called menstrual cycle.
Sporopollenin, an organic material is present in ____.
Sporopollenin is present in exine of pollen grains in plants. It is one of the most resistant organic substances and can withstand high temperature, strong acids and alkali. No enzyme that degrades sporopollenin is so far known. This sporopollenin helps the pollen grain to be well preserved.
Pollen grains are able to withstand extremes of temperature because there exine is composed of_____
The exine is composed of sporopollenin which is the polymer that is resistant to oxidation and leaching.
Sexual reproduction is better mode of reproduction because offspring _____.
During sexual reproduction male and female gametes are fused together to form zygote. The gene from two different sources mix together and develops some new features in new progeny. The new traits help the organisms to survive in adverse condition also.
Ovulation in the females normally takes place during the menstrual cycle _____.
Ovulation is the process of release of ovum from ovary. Menstrual cycle begin with menstrual bleeding. Increase in FSH and LH hormone leads to release of ovum from ovary in the middle of menstrual cycle. In human female ovulation occurs on the 14-15th day of beginning of menstrual cycle.
Which of the following is prevented by unisexuality of flowers?
Unisexuality promotes or favours the cross pollination (xenogamy) and prevent self pollination (Autogamy). Geitnogamy involve transfer of pollen grain between two flowers of the same plant so unisexuality will not prevent geitonogamy.
Which one of the following pairs of plant structure has haploid number of chromosome?
Egg and antipodal cells are haploid structure as they are formed by meiosis cell divisions in which number of chromosome reduce to half. This kinds of division occurs only during gamete formation.
Flower with ovaries having only one or few ovules are generally pollinated by:
Wind is the most common means of pollination in flowering plants. The pollen grain must be light and dry and in large number to facilitate pollination. Flower with one or few ovules are pollinated by wind to ensure fertilisation.
Arrange the following in order of their occurrence in plants.
Sequence of events in reproduction in flowers:
Therefore, the correct answer is option C.
Cleavage include the rapid mitotic division of zygote to form a single layered hollow spherical structure called______.