Question

Cell organelles are the parts of a living cell. Answer the following $3$ questions using the choices provided. A choice may be used once, more than once, or not at all.
Which organelle is not bound by a membrane and is the site of protein synthesis?

• A. Ribosomes
• B. Smooth endoplasmic reticulum
• C. Chloroplasts
• D. Golgi apparatus
• E. Nucleolus

Answer 1

The correct option is A Ribosomes

A. Ribosomes are the non membranous positively charged RNA-protein complexes which are necessary for protein synthesis.

B. Smooth endoplasmic reticulum are membrane bound channels seen in the form of delicate strands and vesicles in the cytoplasm and do not contain ribosomes. SER is mainly involved in synthesis of phospholipids, glycolipids, steroid hormones etc.

C. Chloroplasts are the green coloured plastids and consists of two membranes, an outer membrane and an inner membrane which are separated by an intermembrane space. Chloroplasts are the site of photosynthesis.

D. Golgi apparatus or Golgi bodies are flattened sacs of membrane bound cisternae, vesicles and vacuoles which are present in the form of a complex. They are involved in secretion, storage and packaging of different materials and also post translational modification of proteins.

E. Nucleolus is a spherical body present within the nucleus in close association with the nucleolar organizing region of two or more chromosomes within a set. It is the site of RNA synthesis.

So, the correct answer is Ribosomes.