Assertion (A): | It is important that the organisms should have cells. |
Reason (R): | A cell keeps its chemical composition steady within its boundary. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
Statement I: | In 1838, Matthias Schleiden, a German botanist, examined a large number of plants and observed that the presence of cell wall is a unique character of the plant cells. |
Statement II: | In 1839, Theodor Schwann, a British Zoologist, studied different types of animal cells and reported that cells had a thin outer layer which is today known as the ‘plasma membrane’. |
1. | Statement I is correct; Statement II is correct |
2. | Statement I is correct; Statement II is incorrect |
3. | Statement I is incorrect; Statement II is correct |
4. | Statement I is incorrect; Statement II is incorrect |
I: | All cells arise from pre-existing cells. |
II: | Prokaryotic cells do not have any organelles. |
III: | Eukaryotic cells have only membrane bound organelle. |
IV: | Centrosome helps in cell division in plants and animals. |
Statement I: | Rudolph Virchow proved that all life comes from pre-existing life. |
Statement II: | Louis Pasteur proved that all cells arise from pre-existing cells |
1. | Are primarily used for sensory purposes |
2. | Are composed of microtubules |
3. | Are enclosed in the cell wall |
4. | Rotate rather than whip |
I: | Several ribosomes may attach to a single mRNA and form a chain called polyribosomes or polysome. |
II: | The ribosomes of a polysome translate the mRNA into different proteins. |
1. | Only I | 2. | Only II |
3. | Both I and II | 4. | Neither I nor II |
I: | The main chromosomal DNA is linear |
II: | Plasmid DNA is circular |
Statement I: | Besides flagella, Pili and Fimbriae are also surface structures of the bacteria but do not play a role in motility. |
Statement II: | Pili and fimbriae help attach the bacteria to rocks in streams and also to the host tissues. |
1. | Statement I is correct; Statement II is correct |
2. | Statement I is correct; Statement II is incorrect |
3. | Statement I is incorrect; Statement II is correct |
4. | Statement I is incorrect; Statement II is incorrect |
Identify the correct statement regarding the part of a cell, the structure of which is shown in the given diagram:
1. | It is not found in the plant cells |
2. | It serves to provide an attachment with a surface for a bacterial cell |
3. | The structure is made of a protein called flagellin |
4. | It can be used for movement by a eukaryotic cell |