CBSE Questions for Class 9 Biology The Fundamental Unit Of Life Quiz 1 - MCQExams.com

• 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.
  

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

• The nucleus is the centrally located small spherical structure in an animal cell. It regulates and coordinates various activities of the cell. 
• The cytoplasm is the semi-liquid, colorless, and translucent part of the cell. It is found between the cell membrane and nucleus.
  
• A vacuole is found in the cytoplasm and helps to transport a number of ions against the concentration gradient, excretion, etc. It may or may not be present in an animal cell, if present is very small.
• Plastid is the largest cell organelle. Animal cell lacks plastids. They bear some specific pigments and imparting specific colours to the plant.

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

$$\textbf{ Solution: }$$

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

$$\bullet$$Centrosomes are found only in animal cells and consist of two cylindrical-like structures known as centrioles. These centrioles are involved in the formation of spindle fibre during cell division. 

$$\bullet$$This is a living structure in cells. 

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

$$\bullet$$Vacuoles are the kind of storage sacs that can maintain the osmotic pressure in a cell and store toxic metabolic by-products or end products of plant cells. 

$$\bullet$$This is a non living structure in cells. 

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

$$\bullet$$Ribosomes play an important part in the synthesis of proteins. 

$$\bullet$$Ribosomes are made up of ribonucleic acid (RNA) and protein. 

$$\bullet$$This is a living structure in cells. 

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

$$\bullet$$Mitochondria is the seat of Krebs cycle where the mitochondrial matrix is involved in the oxidation of pyruvate molecules to produce energy in the form of ATP (adenosine triphosphate). 

$$\bullet$$This is a living structure in cells. 

Hence, the correct answer is option (b).

• Hypertonic means that the environment outside of the cell has a higher concentration of solutes than the cell itself. 
• A hypotonic solution is one in which the concentration of solutes is greater inside the cell than outside of it.
• Isotonic means two solutions having the same concentration which means there are an equal number of solute molecules and an equal number of solvent molecules. 
• A liquid with a less solute concentration is called a dilute solution.
  

• Mitosis creates two identical daughter cells each of which contains the same number of chromosomes as their parent cell.
• Meiosis gives rise to four daughter cells, each of which has half the number of chromosomes than parent cells.
• In amitosis, although only two daughter cells are produced, they are not always identical to each other as genetic material (Chromosomal or DNA material) is unequally distributed between the two newly formed cells. 

• The nucleus contains a viscous liquid called nucleoplasm. It contains chromosomes and nuclei. It is surrounded by a nuclear membrane and it helps in the exchange of material between the nucleus and cytoplasm. 
• Protoplasm is the cytoplasm and nucleus of a cell.
  
• The cytosol is the part of the cytoplasm that is not held by any of the organelles in the cell.
  
• The cytoplasm is the part of the cell which is contained within the entire cell membrane. It is the total content within the cell membrane other than the contents of the nucleus of the cell.
  
• So, the correct answer is option B.

• Bacterial cells are primitive cells hence, called prokaryotic cells. 
• They do not possess membrane-bound organelles like mitochondria, lysosomes, etc. They also do not have a well-defined membrane-bound nucleus. 
• Onion peel cell is an eukaryotic cell with a well-defined membrane-bound nucleus, other membrane-bound organelles like mitochondria, vacuole, etc. 

A) Correct Option – C

B)  Explanation for correct option -

• Besides the nucleus, mitochondria is one of the cell organelles which has its own DNA. Its DNA is also known as mitochondrial DNA.
• The mitochondria is also called semi-autonomous organelle as its DNA can replicate independently and synthesize proteins.