CBSE Questions for Class 9 Biology The Fundamental Unit Of Life Quiz 7 - MCQExams.com

• The onion cell is a plant cell, it has a cell wall with a small nucleus and regular cytoplasm.
  
• The cellulose present in the cell walls forms a rectangular brick-like structure.
  

• Onion cell is a plant cell. Plants cells have a cell wall, large vacuole, and a peripheral nucleus. The primary cell wall is made up of cellulose, the large vacuole stores water, nutrients, and waste materials, and a nucleus that is pushed towards the edge.

• CO$$_2$$ is gas so, it moves in and out of the cell by diffusion. Diffusion is a process in which the molecules intermingle due to their kinetic energy and the movement of molecules is from higher concentration to lower concentration. 
• H$$_2$$O moves in and out of the cell by osmosis, in which the water molecules move from lower solute concentration to higher solute concentration through the cell membrane. 

• The surface of the rough endoplasmic reticulum is embedded with ribosomes. They are involved in protein production.
• Lysosomes are also known as suicidal bags because they contain lytic enzymes that can digest cells and foreign materials. 
• Nucleoid is the region that contains the genetic material in a prokaryotic cell (e.g. bacteria). It is not bound by a nuclear membrane. 
• Food vacuoles are found in Amoeba. They are fluid-filled membrane-bound structures. 
• The nucleus contains chromatin material and has a structure known as nucleolus. 

• The Golgi apparatus is the organelle that is responsible for the packaging and transporting the proteins, lipids, etc. synthesized inside the cells.
• The nucleolus is responsible for the synthesis of ribosomal RNA and proteins.
• Ribosomes are responsible for protein synthesis.
• ER plays a major role in protein and lipid synthesis.

• Amoeba, Chlamydomonas, Paramoecium are single celled organisms. 

• Lysosomes are membrane bound cellular organelles. They possess many hydrolytic enzymes for the digestion of cellular waste, debris, as engulfed, killed viruses or bacteria. 
• When cell is in a metabolic crisis then lysosomes digest its own cell or cellular components by releasing enzymes. Hence, lysosomes are called as 'suicide bags' of the cell. 
• The nucleus contains nucleolus and chromatin material visible as entangled mass of thread like structures. 
• The cell theory that all the plants and animals are composed of cells and the cell is the basic unit of life, was presented by two biologists, Schleiden (1838) and Schwann (1839).
• So, the correct answer is option C.

• Cell shape is determined by the function of the cell. Three general factors determine cell shape: the state of the cytoskeleton, the amount of water that is pumped into a cell, and the state of the cell wall.
• Thus, the functioning of the cell determines the cell shape. The statement is True.

Soap contains large amount of solutes. Soap is a hypertonic solution with high amounts of salts. Hence, when washing clothes solute concentration is more in soap water than in cells of hand. Due to this, exosmosis occurs in which the water molecules present in cells of hand move out in soap solution. This is an osmotic process in which the water molecules move from lower solute concentration to higher solute concentration, i.e., from dilute solutions to concentrated solution through a semi-permeable membrane. 

$$\textbf{Correct Option B}$$

$$\textbf{Solution}$$

$$\bullet$$Diffusion is the process of transport of the molecules from a region of their concentration to one of lower concentration. The materials which are diffused as well as the medium in which diffusion occurs can be of any three physical states.