CBSE Questions for Class 11 Medical Biology Cell The Unit Of Life Quiz 14 - MCQExams.com

• A polyribosome is also called as ergosomes. It is a complex of an mRNA molecule and two or more ribosomes that act to translate mRNA instructions into polypeptides. 
• As ribosomes are present in all living organisms i.e both prokaryotic and eukaryotic organisms they are referred to as universal cell organelles. Hence universal cell organelles are Ergosomes.

• starch is a polymeric carbohydrate , which is synthesize by glucose by aprocess called glucogenesis  and regulated by hormon insulin which is secreated by pancrease. major source of starch is potato,rice,peas,etc.
  
• protein is a macromolecule synthesized by RER due to presence of ribosome by  prcess called translation.
  
• SER mainly carry out the synthesis of lipids, and lipids are nothing but fats and fatty acids existing in vegitable and animal kingdom.
  
• ribosomes are not present in SER they are found on surface of RER,hence they are not synthesize by SER.
  

• The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane) is a biological membrane that separates the interior of all cells from the outside environment (the extracellular space) which protects the cell from its environment.
• It controls the movement of substances in and out of cells and organelles. In this way, it is selectively permeable to ions and organic molecules.
  
• Hence Cellular component that is responsible for the exchange of substances into and outside the cell is cell membrane.
• So, the correct answer is 'Cell membrane'.

• The smooth endoplasmic reticulum, or SER, is an organelle found in both animal cells and plant cells.
• Smooth ER consists of a long network of a folded, tube-like structure. The interior of the smooth ER is called the lumen, which is enclosed by a phospholipid membrane, just like the membrane that encloses the entire cell.
  
• Functions of the SER include synthesis of carbohydrates, lipids, and steroid hormones; detoxification of medications and poisons; and storage of calcium ions.
  
• Hence Synthesis of lipids & carbohydrates is regulated by SER.
• So, the correct answer is 'SER'.

• The endoplasmic reticulum without ribosomes is called smooth endoplasmic reticulum(SER).
• The main function of the smooth ER is to make cellular products like hormones and lipids.
  
• Hence Synthesis of lipid is a function of SER.
• So, the correct answer is 'SER'.

• The nucleus contains the genetic material of the cell and thus regulates all the activities of the cell.
• The cell membrane is a semipermeable membrane and it regulates the entry and exit of the molecules.
• The cell wall is a rigid covering mainly present in plant and bacterial cells and provides protection to the plant cell.
• The cytoplasm is the fluid present in the cell. It is present between the plasma membrane and nucleus. It helps to maintaining the shape of the cell and helps in the distribution of cellular materials inside the cell.

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 a cell is in a metabolic crisis then lysosomes digest its own cell or cellular components by releasing enzymes.

• The smooth endoplasmic reticulum (SER) is involved in the synthesis of fatty acids and membrane components, such as lipids. 
• It contains enzymes that help to detoxify and process chemicals like drugs, poisons, and alcohol.

Chromoplasts are plastids, which are involved in different coloured pigment synthesis and their storage. It is responsible for giving different colours to the flowers, fruits. 
The chloroplast is a type of plastid, which produces green coloured pigment. The chloroplast is involved in carrying out photosynthesis. It gives a green colour to leaves. 
Leucoplasts are one the type of plastid, which is non-pigmented. They are involved in storage functions. Such, colourless plastid is present in underground roots, stems. Thus, the correct answer is option A.

• The plasma membrane is approximately 75$$\mathring {A}$$ in thickness. As with most intracellular membranes, 
• it is seen as a trilaminar structure, termed as the unit membrane, with outer darker lines approximately 20$$\mathring {A}$$ wide and an inner lighter line, approximately 35$$\mathring {A}$$ wide. 
• The structure was elucidated by the use of techniques like transmission electron microscopy and free-fracture. Thus, the correct answer is option A.