Question

Which of the following sentences is correct?
A) Cells of all living organisms have a nucleus.
B) Both animal and plant cells have a well-defined cell wall.
C) In prokaryotes there are no membrane bound cell organelles.
D) Cells are formed de novo from abiotic materials.

Answer 1

Hint:The cell is the basic structural, functional, and biological unit of all known organisms. It is the smallest unit. It is composed of membrane, cytoplasm, organelles, and various other components which can vary if it is a plant or an animal, or among the smallest and the largest microorganisms.

Complete answer:
>Prokaryotic cells are characterized by having major biological processes like cell signaling. They are simpler and smaller than eukaryotic cells and lack an organized nucleus, and the genetic material lies in the cytoplasm. Hence, not all the living organisms’ cells have a nucleus.
>The cell wall is only present in plants. It surrounds the plasma membrane of the plant cells and provides tensile strength and protection against mechanical and osmotic stress. It also allows cells to develop turgor pressure, which is the pressure of the cell contents against the cell wall. However, animals are mobile and they need to be flexible. Thus, the cell wall is not required whose function is to keep the body rigid and strong. The rigidity in plants allows them to stand upright without the need for bones.
>Prokaryotes are cellular organisms that lack an envelope-enclosed nucleus. They are asexual and reproduce without the fusion of gametes. They lack mitochondria and other membrane-bound organelles. Hence, it is the correct option.
>According to the cell theory, cells arise from a pre-existing cell and also biomolecules which are considered to be biotic materials. Abiotic material may include temperature, light, etc. which cannot give rise to a cell or a living being.

Hence, the correct answer is option C.

Note: Prokaryotes lack membrane-bound organelles. They generally have a single chromosome, a piece of circular, double-stranded DNA that is located in an area called the nucleoid, because of the absence of a nucleus.