CBSE Questions for Class 8 Biology Cell Structure And Functions Quiz 1 - MCQExams.com

• All of the living organisms are made up of either one or many cells.
• Organisms which have more than one cell are known as multicellular.
• An organism which consists of single cell as whole bosy are known as unicellular organism or single-celled organism.
• The absence of cells is known as acellular.
• So, the correct answer is option B.

• In plants, the cell wall is dead at maturity and, hence, is fully permeable. 
• The cell membrane is, however, living and is biochemically semi-permeable. The cell membrane allows the solvent to pass through but only selective solutes are allowed to come in or move out. The plasma membrane is, thus, a selectively permeable or semi-permeable membrane.
• The cytoplasm is all the contents inside the cell membrane excluding the nucleus. And protoplasm includes cytoplasm, plus, the nucleus of the cell.
  

• Organisms can consist of one cell to many cells. 
• The cell is the structural unit of life. Unicellular organisms are made up of one cell that performs all the functions.
•  Whereas, a multicellular organism that consists of multiple cells and a different group of cells perform different functions which give complexity to the multicellular organisms.

• Cells are called the smallest structural and functional unit of life because all the living organisms are made up of cells and also all the functions taking place inside the body of organisms are performed by cells. 

• Prokaryotic cells do not have membrane-bound organelles such as the nucleus, mitochondria, Golgi, and endoplasmic reticulum, etc. 
• While in eukaryotic cells, membrane-bound organelles and non-membrane-bound organelles (ribosomes and centriole) both are present.
• The cell wall is present in prokaryotic cells (bacteria) as well as in some eukaryotic cells, like fungal and plant cells.
• Hence, the eukaryotic cells differ from prokaryotic cells in having a well-organised nucleus and mitochondria.

• The first characteristic of a living thing is that they are made up of cells. A cell is a basic building block of all organisms. 
• It is the smallest unit of organization in a biosphere. A cell performs the life process to maintains the survival of an organism.

• Cells are called an amazing world in itself because all the living organisms are made up of cells and also all the functions taking place inside the body of organisms are performed by cells. 
• These have the specialized enzymes, which catalyze the biochemical reaction and regulates the specialized functions of the body such as the conversion of nutrients into the energy, reproduction in unicellular and division or replication in multicellular.

• Cells are called the structural and functional unit of life because all the living organisms are made up of cells and also all the functions taking place inside the body of organisms are performed by cells. Cells provide specific conditions, for the occurrence of the metabolic reactions. These have specialized enzymes, which catalyze the biochemical reaction and regulates the functions of the body.

• The cells are microscopic in size and are not visible to the unaided eye with the size from 0.5 micrometers to 50 micrometers. 
• They need to be enlarged or magnified by a microscope. 
• The electron microscope discovered by Knoll and Ruska was able to magnify the cellular structure.

• Cells are called the structural and functional unit of life because all the living organisms are made up of cells, maybe one cell or multiple cells and perform all the life process for survival.

$$\textbf{Correct option: }$$ A

$$\textbf{ Solution: }$$

$$\textbf{ Option (a): }$$

$$\bullet$$Unicellular organisms are made up of one cell that performs all the functions and metabolism of the organism. 

$$\bullet$$These are also known to be single-celled organisms.

$$\textbf{ Option (b): }$$

$$\bullet$$Acellular organism are those organism which are present outside the host cell organism in the form of non living organism and behave as a living organism inside the host organism. 

$$\bullet$$For example, viruses, viroids and prions. 

$$\textbf{ Option (c): }$$

$$\bullet$$Multicellular organism contains many cells especially living in nature. 

$$\bullet$$Different cell organizes to form tissues which perform different functions and activities. 

$$\bullet$$Examples of organisms that are multicellular are humans, animals, and plants.

• Each organ is further made up of smaller parts called tissues. A tissue is a group of similar cells performing a specific function.
• Cells are the basic building blocks of living things. 
• Pseudopodia is a retractile process of the cytoplasm of a cell that functions especially as an organ of locomotion and food-acquiring.