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Biology Class 10 CBSE Syllabus Topics
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Posted : March 18, 2024 3:10 pm
Unicellular organisms, such as amoebas and paramecia, procure food, exchange gases, and excrete metabolic wastes through various mechanisms:-
1. Procuring Food: Unicellular organisms use different methods to procure food:-
- Phagocytosis: Amoebas, for example, use phagocytosis, where they engulf food particles such as bacteria or organic debris into their cell membrane, forming a food vacuole.
- Ciliary or flagellar movement: Paramecia use their cilia to sweep food particles, such as bacteria or algae, into their oral groove, where they are engulfed and enclosed in a food vacuole.
2. Exchange of Gases: Unicellular organisms exchange gases with their environment primarily through diffusion across their cell membranes. This occurs as follows:-
- Oxygen enters the cell and carbon dioxide exits the cell through diffusion across the cell membrane, driven by concentration gradients.
- In some unicellular organisms, such as aquatic protists like amoebas and paramecia, gases are exchanged directly with the surrounding water.
3. Excretion of Metabolic Wastes: Unicellular organisms eliminate metabolic wastes through diffusion across the cell membrane or by expulsion from the cell:-
- Ammonia, a common metabolic waste product in many unicellular organisms, diffuses out of the cell membrane into the surrounding environment.
- Contractile vacuoles: Some unicellular organisms, like paramecia living in freshwater environments, use contractile vacuoles to remove excess water and waste products by expelling them from the cell.
Overall, these mechanisms allow unicellular organisms to obtain nutrients, exchange gases, and excrete waste products necessary for their survival.
Posted : March 23, 2024 9:06 pm
