Question

Which of the following does not differ in E. coli and Chlamydomonas?
A. Ribosomes
B. Chromosomal organization
C. Cell wall
D. Cell membrane

Answer 1

E. coli is a rod-shaped bacteria that consists of an outer membrane, inner membrane and an inner cytoplasmic membrane. E. coli is a prokaryotic organism. They are found in faecal contaminated environments such as water, soil and mud. Chlamydomonas is a kind of green algae. It is a unicellular and eukaryotic organism. They live in moist soil, freshwater, and the sea.

Complete explanation:
Option A Ribosomes: E. coli contains around $10,000$ and $70,000$ ribosomes in each cell. Ribosomes consist of catalytic rRNAs and polypeptides. They have $70$ type ribosomes. The ribosomes of Chlamydomonas contain many helical repeat proteins and are of 80s type.
Option A is incorrect.
Option B Chromosomal organization: The prokaryotic E. coli does not have a well-defined nucleus. Its DNA is not associated with histone proteins. Chlamydomonas have a well-defined nucleus and have histone proteins for chromosomal organization.
Option B is incorrect.
Option C Cell wall: The cell wall of E. coli is thin and made up of peptidoglycan. The cell wall is multi-layered. Chlamydomonas has a rigid cell wall made of cellulose.
Option C is incorrect.
Option D Cell membrane: The cell membrane of Chlamydomonas and E. coli are triple layered and made of carbohydrates. This is a similarity between these organisms.
Option D is correct.

Therefore, option D. Cell membrane is the correct answer

Note:
Both the E. coli and Chlamydomonas contain flagella for their movement. The flagella of E. coli consist of three distinct parts namely the filament, the hook and the basal body. They are made up of different types of proteins. The Chlamydomonas has one pair of flagella projecting from the anterior end of the cell. The flagella enables the cell to move in breast-stroke like movements. They are also made up of proteins such as centrin. This forms as another similarity between E. coli and Chlamydomonas.