Question

Identify the components labeled A, B, C, and D in the diagram above from the list (i) to (viii).

Components : (i) Cristae of mitochondria
(ii) Inner membrane of mitochondria
(iii) Cytoplasm
(iv) Smooth endoplasmic reticulum
(v) Rough endoplasmic reticulum
(vi) Mitochondrial matrix
(vii) Cell vacuole
(viii) Nucleus
The correct components are
(A)A - (v), B - (i), C - (iii), D - (ii)
(B)A - (v,) B - (iv), C - (viii), D - (iii)
(C)A - (i), B - (iv), C - (viii), D - (vi)
(D)A - (vi,) B - (v), C - (iv), D - (vii)

Answer 1

Hint: The different components can easily be identified by looking at their location from the nucleus and by looking at their morphological characteristics, for example, the organelle which helps in protein formation has ribosomes attached with it.

Complete answer:
In the diagram given in the question, A represents the structure of the rough endoplasmic reticulum (RER). RER is recognized easily because it is associated with the small dense granules called ribosomes, along the outer border of its membrane.
ER in some types not associated with the ribosome (represented by B) hence called the smooth endoplasmic reticulum.
C represents the structure of the nucleus surrounded by a nuclear envelope. The cytoplasm is defined as the jelly-like fluid, specifically the protoplasmic fluid which surrounds the nucleus, represented by structure D.
Additional Information:
- Endoplasmic reticulum in the animal cell constitutes more than half of the membranous contents of the cell.
- It is surrounded by two membranes, the outer membrane, and the inner membrane
- The ER divides the intracellular spaces of the cell into two different compartments which are known as the luminal compartment and the extraluminal compartment.
- On the RER, ribosomes are attached to the surface. The presence of ribosomes plays an important role in the synthesis of proteins.
- Smooth endoplasmic reticulum is devoid of ribosomes. It plays an important role in synthesizing lipids. In animal cells, lipid-like steroidal hormones are synthesized in the smooth endoplasmic reticulum.

So, the correct answer is ‘A - (v,) B - (iv), C - (viii), D - (iii)’

Note:
-The term endoplasmic reticulum was coined by the K.Porter in the year 1953.
-Some of the proteins are stored in the endoplasmic reticulum and later they are sent into the Golgi apparatus which lies next to the endoplasmic reticulum. A smooth endoplasmic reticulum in the liver helps in the detoxification of harmful chemicals and drugs.