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Which of the following unicellular organism change their shape?
Yeast
Amoeba
Paramoecium
Bacteria
Amoeba
Amoeba is a unicellular organism that possesses an irregular shape. It continuously changes its shape by forming temporary finger-like projections called pseudopodia (false feet), which allow it to move and engulf food.
Amoeba is a unicellular organism that possesses an irregular shape. It continuously changes its shape by forming temporary finger-like projections called pseudopodia (false feet), which allow it to move and engulf food.
Think of an Amoeba like a blob of dough or jelly that you can push and pull into different shapes without breaking it, as it has no rigid outer wall.
Amoeba = Always Moving Or Changing Body Architecture
The shape change is driven by the dynamic reorganization of the actin cytoskeleton within the cytoplasm. When the cytoplasm flows into a specific region, the cell membrane extends to form pseudopodia, a process known as amoeboid movement.
Amoeba is a eukaryote belonging to the kingdom Protista.
Pseudopodia are essential for both locomotion and phagocytosis (cell feeding).
Unlike bacteria or yeast, which have rigid cell walls (peptidoglycan or chitin, respectively), the Amoeba has only a flexible cell membrane.
The absence of a rigid cell wall is the primary reason it can change shape.
Flexibility allows for efficient navigation through complex substrates.
Enables simple engulfment of prey via phagocytosis.
Lack of structural support limits size and environmental resistance compared to rigid-walled cells.
Study of cellular motility and cytoskeleton dynamics.
Model organism for understanding phagocytic immune mechanisms.
Yeast are fungi with a rigid cell wall, giving them an ovoid/spherical shape.
Paramoecium has a fixed, slipper-like shape maintained by a pellicle.
Bacteria exhibit fixed shapes like cocci (spherical), bacilli (rod), or spirilla due to their peptidoglycan cell wall.
B is correct тАФ The Amoeba is a unicellular organism characterized by its ability to constantly change its body shape through the formation of pseudopodia.
In competitive exams, remember that the presence or absence of a cell wall is the key differentiator for cell shape stability. Organisms without cell walls, like Amoeba, are morphologically fluid.
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