Study the following diagram showing various stages of binary fission in Amoeba, the correct sequence of these diagrams should be:
I,IV, III, II, V
III, I, IV, II, V
I, II, IV, III, V
I, III, IV, II, V
(4)
Asexual reproduction is a process of reproducing the offspring through simple division of cells, this type of reproduction is observed in single cell organisms, it does not undergo fusion of gametes, therefore, the offspring produced by asexual reproduction are genetically identical. The asexual reproduction is further divided into; binary fission, budding, fragmentation, and sporogenesis.
The binary fission is an asexual reproduction observed in amoeba. After the replication process through mitotic division, the amoeba cell divides into two equal halves and these are considered as the daughter cells. In this process, the daughters cells thus produced through cell division are identical to each other.
The amoebas that are about to divide grow eventually larger, the nucleus gets extended and divides into two. The nuclear division is followed by the cytoplasmic division. Therefore, two amoebas are produced from a single amoeba.
Which of the following statements about binary fission is true?
Some multicellular organisms also reproduce through binary fission.
Binary fission produces two new organisms.
Binary fission in Amoeba happens only in the vertical plane.
Binary fission in Leishmania can happen in any plane.
(2)
Only unicellular organisms reproduce through binary fission. In binary fission, a unicellular organism (a cell) divides to form two unicellular organisms (two cells). Binary fission in Amoeba can happen in any plane. Binary fission in Leishmania happens in a definite orientation (plane) to the body because Leishmania has somewhat organised structure.
A feature of reproduction that is common to Amoeba, Yeast and Bacterium is that:
they are all multicellular
they are all unicellular
they reproduce only sexually
they reproduce asexually
(4)
Amoeba, Yeast and Bacterium are unicellular organisms and reproduce asexually.
In the list of organisms given below, those that reproduce by the asexual method are:
(i) banana (ii) dog (iii) yeast (iv) Amoeba
(ii) and (iv)
(i), (iii) and (iv)
(i) and (iv)
(ii), (iii) and (iv)
(2)
Asexual reproduction takes place without the process of gamete formation and only one parent is needed. Examples include Amoeba which reproduces by binary fission (division of cell into two similar cells).
Yeast reproduces by budding (small buds develop from body wall of parent that separate and grow further).
Banana reproduces by vegetative propagation (Vegetative parts of a plant such as root, stem, etc., can produce new plants).
In dog, sexual reproduction takes place (i.e., it involves two sexes — male and female whose gametes fuse constituting sexual reproduction).
Offspring formed by asexual method of reproduction have greater similarity among themselves because:
(i) Asexual reproduction involves only one parent.
(ii) Asexual reproduction does not involve gametes.
(iii) Asexual reproduction occurs before sexual reproduction.
(iv) Asexual reproduction occurs after sexual reproduction
(i) and (ii)
(i) and (iii)
(ii) and (iv)
(iii) and (iv)
(1)
Offspring have greater similarity as only one parent is involved in asexual reproduction thus no gametes are formed. The basis of asexual reproduction is mitosis (division of a nucleus into two identical daughter nuclei). Each daughter nucleus has same genetic make up because of replication of parental DNA. The new offspring produced are called clones.
A feature of reproduction that is common to Amoeba, Spirogyra and yeast is that:
they reproduce asexually.
they are all unicellular.
they reproduce only sexually.
they are all multicellular.
(1)
Amoeba and yeast are unicellular while Spirogyra is multicellular. But all the three reproduce asexually.
In Spirogyra, asexual reproduction takes place by:
breaking up of filaments into smaller bits.
division of a cell into two cells.
division of a cell into many cells.
formation of young cells from older cells.
(1)
In Spirogyra, asexual reproduction takes place by fragmentation, i.e., the organism simply breaks up into smaller pieces upon maturation. Each piece grows into new individual without forming any gametes.
Name the process shown in the above diagram of getting back a full organism from its body parts.
Regeneration
Budding
Fragmentation
Fission
(1)
The process of getting back a full organism from its body parts is called regeneration. The simple animals like Hydra and Planaria show regeneration. If the body of Planaria gets cut into a number of pieces, then each body piece can regenerate into a complete Planaria by growing all the missing parts. The regeneration of an organism from its cut body part occurs by the process of growth and development. The cells of cut body part divide rapidly to make a ball of cells. The cells then become specialised to form different types of tissues which again form various organs and body parts.
What happens when a Planarian (plural - Planaria) is cut into many fragments?
All fragments regenerate into new organisms.
Only the head containing fragment regenerates into a new organism.
Nearly half of the fragments regenerate into new organisms.
No changes are seen in fragments. Planaria reproduce by budding.
(1)
Cells that cause regeneration are present all over the body of a Planarian. So, when a Planarian is cut into many fragments, all fragments regenerate into new organisms.
Asexual reproduction takes place through budding in:
Amoeba
Yeast
Plasmodium
Leishmania
(2)
Both asexual and sexual reproduction are possible for yeast. Budding is the process through which yeast multiply asexually.
