Question

• Choose two organelles, describe their structure and function, and explain the functional relationship between the two organelles.

Answer 1

Two organelles are:

1) Nucleus

2) Endoplasmic reticulum

1) Nucleus
- bounded by double nuclear membrane
- composed of Chromatins and chromosomes, nucleolus and nuceloplasm
- directing the cell metabolism and site for DNA replication
- absent in prokaryotes
- present in eukaryotes animals And
Plants.

- They direct the cellular functions

- RNA formed in the nucleus are sent to Ribosomes of the endoplasmic reticulum where proteins are synthesized accordingly.

2) Endoplasmic Reticulum:

They are of two types:

rough endoplasmic reticulum :
- double membrane bound
- composed of cisternae tubules and vesicles. Ribosomes attached to its surface
- site of protein synthesis
- present in eukaryotes plants and animals
- absent in prokaryotes

- They are responsible for synthesis of proteins and their modification as the ribosomes are attached to its surface.

Smooth endoplasmic reticulum :
- double membrane bound
- similar to rough endoplasmic reticulum except ribosomes are absent.

- site of Lipid and steroid synthesis
- present in eukaryotes plants and animals
- absent in prokaryotes