Practicing Success

Target Exam

CUET

Subject

Biology

Chapter

Cell : The Unit of Life

Question:

Read the following statements and find out the incorrect statement.

Options:

Prokaryotes are generally smaller and multiply more rapidly than the eukaryotic cells.

Glycocalyx could be a loose sheath called slime layer in some, while in others it called the capsule.

The plasma membrane of prokaryotes is structurally dissimilar to that of eukaryotes.

Chromatophores are the membranous extension into the cytoplasm of cyanobacteria which contain pigments.

Correct Answer:

The plasma membrane of prokaryotes is structurally dissimilar to that of eukaryotes.

Explanation:

The correct answer is Option (3) - The plasma membrane of prokaryotes is structurally dissimilar to that of eukaryotes.

Cells that have membrane bound nuclei are called eukaryotic whereas cells that lack a membrane bound nucleus are prokaryotic. In both prokaryotic and eukaryotic cells, a semi-fluid matrix called cytoplasm occupies the volume of the cell. 

Besides the nucleus, the eukaryotic cells have other membrane bound distinct structures called organelles like the endoplasmic reticulum (ER), the golgi complex, lysosomes, mitochondria, microbodies and vacuoles. The prokaryotic cells lack such membrane bound organelles.

Ribosomes are non-membrane bound organelles found in all cells – both eukaryotic as well as prokaryotic. Within the cell, ribosomes are found not only in the cytoplasm but also within the two organelles – chloroplasts (in plants) and mitochondria and on rough ER .

The prokaryotic cells are represented by bacteria, blue-green algae, mycoplasma and PPLO (Pleuro Pneumonia Like Organisms). They are generally smaller and multiply more rapidly than the eukaryotic cells.

Glycocalyx differs in composition and thickness among different bacteria. It could be a loose sheath called the slime layer in some, while in others it may be thick and tough, called the capsule. The cell wall determines the shape of the cell and provides a strong structural support to prevent the bacterium from bursting or collapsing.

The plasma membrane is selectively permeable in nature and interacts with the outside world. This membrane is similar structurally to that of the eukaryotes.

 In some prokaryotes like cyanobacteria, there are other membranous extensions into the cytoplasm called chromatophores which contain pigments.