What is the disadvantage of parthenogenesis?
Wastage of germplasm
Retention of genotype
Lack of adaptability
Variety in population
(3)
Since there is no fertilisation of gametes in parthenogenesis, there will be no crossing over of genes. This hence causes no variations in the generations. Which makes it difficult for the offspring to adapt to the changing environmental conditions.
Variation patterns are studied in the offspring of sexually and asexually reproducing organisms.
State your observation:
More variations are observed in the offspring of sexually reproducing organisms.
More variations are observed in the offspring of asexually reproducing organisms.
No difference in variation is observed in offspring of sexually and asexually reproducing organisms.
Cannot be determined.
(1)
There is always a possibility of diversity of characters in the offsprings of sexually reproducing organism because the offspring is formed as a result of fusion of two gametes produced by two different individuals: the male and the female parents. So, there is an opportunity for new combinations of characters.
Characters transmitted from parents to offspring are present in:
cytoplasm
ribosome
golgi bodies
genes
(4)
Characters are transmitted from parents to offspring through genes. Genes are the heredity units of the body in living organisms. Chromosomes in the nucleus of a cell contain information for the inheritance of features from parents in the form of DNA (Deoxyribonucleic acid). This DNA contains genes.
Characters that are transmitted from parents to offspring during reproduction show:
only similarities with parents.
only variations with parents.
both similarities and variations with parents.
neither similarities nor variations.
(3)
In sexual reproduction, the offspring are not identical to the parents or to one another. This is because the offspring receive some genes from mother and some from father.
Due to the mixing of genes on re-establishment of number of chromosome in various different combinations, the offspring show both similarities and variations with characters of parents.
The number of chromosomes in parents and offspring of a particular species remains constant due to:
doubling of chromosomes after zygote formation.
halving of chromosomes during gamete formation.
doubling of chromosomes after gamete formation.
halving of chromosomes after gamete formation
(2)
The number of chromosomes in parents and offspring of a particular species remains constant due to halving of chromosomes during gamete formation. The gametes are special type of cells which contain only half the amount of DNA as compared to normal cells of an organism. So, when a male gamete combines with a female gamete during sexual reproduction, then the new cell 'zygote' will have normal amount of DNA.
Reproduction is essential for living organisms to order to
keep the individual organism alive.
fulfill their energy requirement.
maintain growth.
continue the species generation after generation.
(4)
Reproduction is not essential for the survival of an individual, but it is an important function of a living being as it helps an organism to perpetuate its own kind.
Through this process, new individuals are produced, that grow and reproduce again, so as to continue the species generation after generation. Reproduction is a process to maintain the progeny of an organism.
In the following figure different stages of binary fission in Amoeba are depicted, which are not in proper sequence.
The correct sequence is :
II, III, IV, I
I, II, IV, III
III, IV, II, I
I, III, IV, II
(1)
In Amoeba, binary fission is an asexual method of reproduction. (II) represents the parent cell, which replicates the genetic material as shown in (III). The cytoplasm divides after karyokinesis, resulting in two cells (IV). The two cells illustrated in (I) are the daughter cells that result from binary fission.
The ability of a cell to divide into several cells during reproduction in Plasmodium is called:
Budding
Reduction division
Multiple fission
Binary fission
(3)
Plasmodium reproduces asexually after feeding on red blood cells, a process known as schizogony or multiple fission. Plasmodium divides into numerous cells during multiple fission.
Which of the following two combinations are correct?
| Multiple Fission | Binary Fission |
|---|---|
| (a) 2 daughter cells are formed. | Many daughter cells are formed. |
| (b) Both the nucleus and cytoplasm divide simultaneously. | First, the nucleus divides and is surrounded by cytoplasm |
| (c) Divides repeatedly. | Divides only once. |
| (d) Includes a definite pattern of division. | Has no definite pattern of division. |
a
b
c
d
(3)
Both binary fission and multiple fission are modes of asexual reproduction and occur with the presence of only one parent. In binary fission, the parent cell divides itself into two equal and identical daughter cells. It is the most common form of reproduction in prokaryotes such as bacteria. In multiple fission, a single parent cell is divided into many daughter cells. It is the most common form of reproduction in protists and in some parasitic species.
In which of the following aspects does multiple fission differ from binary fission?
(i) Number of offsprings produced.
(ii) Level of genetic variation in offsprings.
(iii) Number of parents involved.
(iv) Multiple fission happens in Plasmodium whereas binary fission happens in Leishmania.
Only (i) is correct
Both (i) and (iv) are correct
(iii) is correct
(ii) is correct
(2)
Multiple fission produces many off-springs whereas binary fission produces only two. Off-springs produced through multiple fission as well as binary fission are genetically identical to each other and to their parents. Both multiple fission and binary fission require only one parent. Plasmodium, the protozoan that causes malaria reproduces through multiple fission. Leishmania causes Kala-azar and it reproduces through binary fission.
