Keeping in view the 'fluid mosaic model for the structure of cell membrane, which one of

the following statements is correct with respect to the movement of lipids and proteins

from one lipid monolayer to the other (described as flip-flop movement)?

1. Both lipids and proteins can flip-flop

2. While lipids can rarely flip-flop, proteins cannot

3. While proteins can flip-flop, lipids cannot

4. Neither lipids, nor proteins can flip-flop

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

The two subunits of ribosome remain united at a critical ion level of

1. copper

2. manganese

3. magnesium

4. calcium

Vacuole in a plant cell:

1. is membrane-bound and contains storage proteins and lipids

2. is membrane-bound and contains water and excretory substances

3. lacks membrane and contains air

4. lacks membrane and contains water and excretory substances

In germinating seeds fatty acids are degraded exclusively in the

1. proplastids

2. glyoxysomes

3. peroxisomes

4. mitochondria

Which one of the following is not a constituent of cell membrane ?

1. Cholesterol

2. Glycolipids

3. Proline

4. Phospholipids

Lysozyme that is present in perspiration, saliva and tears, destroys:

1. certain fungi

2. certain types of bacteria

3. all viruses

4. most virus-infected cells

Select the wrong statement from the following:

1. both chloroplasts and mitochondria contain an inner and an outer membrane

2. both chloroplasts and mitochondria have an internal compartment, the thylakoid

space bounded by the thylakoid membrane

3. both chloroplasts and mitochondria contain DNA

4. the chloroplasts are generally much larger than mitochondria

Which of the following statements regarding mitochondrial membrane is not correct?

1. The outer membrane is permeable to all kinds of molecules

2. The enzymes of the electron transfer chain are embedded in the outer membrane

3. The inner membrane is highly convoluted forming a series of infoldings

4. The outer membrane resembles a sieve

Which of the following statements regarding cilia is not correct ?

1. The organized beating of cilia is controlled by fluxes of Ca²⁺ across the membrane

2. Cilia are hair-like cellular appendages

3. Microtubules of cilia are composed of tubulin

4. Cilia contain an outer ring of nine doublet microtubules surrounding two single

microtubules