Chapter 07 How do Organisms Reproduce? Questions-02
Questions
1. How does binary fission differ from multiple fission?
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Answer
In binary fission, a single cell divides into two equal halves. Amoeba and Bacteria divide by binary fission.
Binary fission in Amoeba
In multiple fission, a single cell divides into many daughter cells simultaneously. Amoeba andPlasmodium divide by multiple fission.
Multiple fission in Plasmodium
2. How will an organism be benefited if it reproduces through spores?
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Answer
There are many advantages, if an organism reproduces through spores.
Advantages of spore formation:
- Large numbers of spores are produced in one sporangium.
- $\quad$ Spores are distributed easily by air to far-off places to avoid competition at one place.
- Spores are covered by thick walls to prevent dehydration under unfavourable conditions.
3. Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?
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Answer
Simple organisms such as Hydra and Planaria are capable of producing new individuals through the process of regeneration. The process of regeneration involves the formation of new organisms from its body parts. Simple organisms can utilize this method of reproduction as their entire body is made of similar kind of cells in which any part of their body can be formed by growth and development.
However, complex organisms have organ-system level of organization. All the organ systems of their body work together as an interconnected unit. They can regenerate their lost body parts such as skin, muscles, blood, etc. However, they cannot give rise to new individuals through regeneration.
4. Why is vegetative propagation practised for growing some types of plants?
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Answer
Vegetative propagation is the ability of the plants to reproduce by producing new plants from the vegetative plant parts such as leaf, stem, or roots under appropriate conditions. This method is the only means of reproduction for some seedless plant varieties such as banana, rose, and jasmine. However, this method of reproduction is also used for agricultural purposes in commercial production of some plants such as sugarcane, grapes, roses, etc.
5. Why is DNA copying an essential part of the process of reproduction?
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Answer
DNA (Deoxyribonucleic acid) copying is an essential part of reproduction as it passes genetic information from parents to offspring. It determines the body design of an individual. The reproducing cells produce a copy of their DNA through some chemical reactions and result in two copies of DNA. The copying of DNA always takes place along with the creation of additional cellular structure. This process is then followed by division of a cell to form two cells.
