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

Stroma in the chloroplasts of higher plants contains

1. light-independent reaction enzymes

2. light-dependent reaction enzymes

3. ribosomes

4. chlorophyll

Middle lamella is mainly composed of

1. hemicellulose

2. muramic acid

3. calcium pectate

4. phosphoglycerides

Plasmodesmata are

1. lignified cemented layers between cells

2. locomotory structures

3. membranes connecting the nucleus with plasmalemma

4. connections between adjacent cells

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:

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