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. |
I: | are formed by the extensions of plasma membrane into the cell. |
II: | help in cell wall formation, DNA replication and distribution to daughter cells. |
III: | contain pigments in cyanobacteria. |
1. | the enclosure has pores which membranes do not |
2. | the enclosure is made up of two membranes |
3. | the chemical composition is inconsistent with cellular membranes |
4. | the enclosure does not enclose the nucleolus |
In the following diagrams, each shows a section of the cell surface membrane to illustrate the fluid mosaic model. Which diagram is the most accurate?
(The black shape represents cholesterol, and the gray shape represents protein.)
1. | |
2. | |
3. | |
4. | |
1. | Substances with hydrophobic moiety |
2. | Substances with hydrophilic moiety |
3. | All substances, irrespective of hydrophobic and hydrophilic moiety |
4. | Substances which are soluble in lipids |
A. | The hydrolytic enzymes of lysosomes are active under alkaline pH |
B. | Lysosomes are membrane-bound structures |
C. | Lysosomes are formed by the process of packaging in the endoplasmic reticulum |
D. | Lysosomes have numerous hydrolytic enzymes |
1. | A only | 2. | B, D Only |
3. | A, D Only | 4. | A, C Only |
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 |
1. | in the cytoplasm |
2. | within the chloroplasts (in plants) |
3. | within the mitochondria |
4. | within the rough ER. |
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 |