Cell: The Unit of Life

Select the alternative giving correct identification and function of the organelle 'A' in the diagram [Figure]

1. Golgi body - provides packaging material
2. Mitochondria - produce cellular energy in the form of ATP
3. Endoplasmic reticulum - synthesis of lipids
4. Lysosomes - secrete hydrolytic enzymes

Which one of the following cellular parts is correctly described ?

1. Lysosomes - optimally active at a pH of about 8.5
2. Centrioles - sites for active RNA synthesis
3. Thylakoids - flattened membranous sacs forming the grana of chloroplasts
4. Ribosomes - those on chloroplasts are larger (80S) while those in the cytoplasm are smaller (70S)

Which one of the following structures is an organelle within an organelle ?

1. Mesosome
2. Peroxisome
3. Ribosome
4. ER

Ribosomal RNA is actively synthesized in

1. Nucleolus
2. Ribosomes
3. Lysosomes
4. Nucleoplasm

Select the correct statement from the following regarding cell membrane

1. Na+ and K+ ions move across cell membrane by passive transport
2. Lipids are arranged in bilayer with polar heads towards the inner part
3. Proteins make up 60 to 70% of the cell membrane
4. Fluid mosaic model of cell membrane was proposed by Singer and Nicolson

What is true about ribosomes ?

1. These are self-splicing introns of some RNAs.
2. These are found only in eukaryotic cells
3. These are composed of ribonucleic acid and proteins
4. The prokaryotic ribosomes are 80 S, where 'S' stands for sedimentation coefficient.

Which one of the following does not differ in E. coli and Chlamydomonas ?

1. Chromosomal Organization
2. Cell wall
3. Ribosomes
4. Cell membrane

Which one of the following is not considered as a part of the endomembrane system ?

1. Vacuole
2. Lysosome
3. Golgi complex
4. Peroxisome

The figure below shows the structure of a mitochondrion with its four parts labelled (A), (B), (C) and (D). Select the part correctly matched with its function. [Figure]

1. Part (B) : Inner membrane – forms infoldings called cristae
2. Part (C) : Cristae – possess single circular DNA molecule and ribosomes
3. Part (A) : Matrix – major site for respiratory chain enzymes
4. Part (D) : Outer membrane – gives rise to inner membrane by splitting

In eubacteria, a cellular component that resembles eukaryotic cell is

1. plasma membrane
2. nucleus
3. ribosomes
4. cell wall