The given statements describe a group of organisms. RE (i)...

Name: Problem 35, Chapter 2: Objective NCERT at your FINGERTIPS: Biology
Uploaded: 2021-11-05T18:10:43-08:00
Duration: 1 min 29 s
Channel: Aflah M
Description: The given statements describe a group of organisms. RE (i) Instead of a cell wall they have a protein rich pelicle making their body flexible. (ii) They have 2 flagella, a short and a long one. (iii) They show mixotrophic nutrition. (iv) They are connecting link between- plants and animale. Which of the following group is referred here? (a) Dinoflagellates (b) Slime moulds (c) Desmids and diatoms

The given statements describe a group of organisms. RE (i) Instead of a cell wall they have a protein rich pelicle making their body flexible. (ii) They have 2 flagella, a short and a long one. (iii) They show mixotrophic nutrition. (iv) They are connecting link between- plants and animale. Which of the following group is referred here? (a) Dinoflagellates (b) Slime moulds (c) Desmids and diatoms

The given statements describe a group of organisms. RE
(i) Instead of a cell wall they have a protein rich pelicle making their body flexible.
(ii) They have 2 flagella, a short and a long one.
(iii) They show mixotrophic nutrition.
(iv) They are connecting link between- plants and animale. Which of the following group is referred here?
(a) Dinoflagellates
(b) Slime moulds
(c) Desmids and diatoms

Key Concepts

Dinoflagellates

Dinoflagellates are a class of protists that play a crucial ecological role, particularly in marine environments. They are characterized by a flexible, protein-rich pellicle that replaces the typical rigid cell wall, enabling them to change shape. Their cell structure is distinguished by having two flagella of unequal lengths, which aids in their intricate locomotion, including spinning movements. Moreover, they exhibit mixotrophic nutrition, meaning they can photosynthesize and also ingest other organisms, thereby bridging characteristics of both plants and animals.

Mixotrophic Nutrition

Mixotrophic nutrition is a metabolic strategy where organisms combine autotrophic and heterotrophic modes of obtaining energy and carbon. This dual approach allows organisms like certain protists to harness energy from sunlight through photosynthesis as well as from consuming organic material, providing a survival advantage in environments where resource availability fluctuates.

Flagellar Structure

Flagella are tail-like extensions of cells that facilitate movement in many microorganisms. In dinoflagellates, the presence of two flagella, one longer and one shorter, is significant because it enables complex movements, enhancing their ability to navigate aquatic environments. This arrangement is a key characteristic that helps in distinguishing them from other protist groups.

Pellicle

A pellicle is a layer of protein or proteinaceous material found beneath the cell membrane in many protists. Unlike a rigid cell wall, the pellicle provides flexibility while still maintaining the cell’s shape and structure. In dinoflagellates, this feature is essential as it contributes to the dynamic morphology of the cells, allowing them to adapt to varying environmental conditions.

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