What is true about ribosomes?
1. The prokaryotic ribosomes are 80 S, where S stands for sedimentation coefficient
2. These are composed of ribonucleic acid and proteins
3. These are found only in eukaryotic cells
4. These are self-splicing introns of some RNAs
Select the correct statement from the following regarding cell membrane.
1. Na+ and K ions move across cell membrane by passive transport
2. Proteins make up 60 to 70% of the cell membrane
3. Lipids are arranged in a bilayer with polar heads towards the inner part
4. Fluid mosaic model of cell membrane was proposed by Singer and Nicolson
Peptide synthesis inside a cell takes place in
1. mitochondria
2. chromoplast
3. ribosomes
4. chloroplast
Which one of the following structures between two adjacent cells is an effective transport
pathway?
1. | Plasmodesmata | 2. | Plastoquinones |
3. | Endoplasmic rcticulum | 4. | Plasmalemma |
Which one of the following has its own DNA?
1. Mitochondria
2. Dictyosome
3. Lysosome
4. Peroxisome
The main arena of various types of activities of a cell is
1. plasma membrane
2. mitochondrion
3. cytoplasm
4. nucleus
The plasma membrane consists mainly of
1. phospholipids embedded in a protein bilayer
2. proteins embedded in a phospholipid bilayer
3. proteins embedded in a polymer of glucose molecules
4. proteins embedded in a carbohydrate bilayer
Middle lamella is mainly composed of
1. hemicellulose
2. muramic acid
3. calcium pectate
4. phosphoglycerides
Cytoskeleton is made up of
1. calcium carbonate granules
2. callose deposits
3. cellulosic microfibrils
4. proteinaceous filaments
Polysome is formed by
1. several ribosomes attached to a single mRNA
2. many ribosomes attached to a strand of endoplasmic reticulum
3. a ribosome with several subunits
4. ribosomes attached to each other in a linear arrangement