Class 9 Science Chapter 5 MCQ

Each cell is bounded by an extremely delicate, thin elastic living membrane, called the plasma membrane. The plasma membrane is made up of two layers of liquid or fat molecules with protein molecules which is sandwitched between lipid layer. The structure of plasma membrane can be observed under and electron microscope only. It is a selectively permeable membrane which allows the flow of only some substances into the cell and out of the cell. Viruses do not have any membranes. Functions: a) It gives a definite shape to the cell. b) It provides protection to the in contents of the cell. c) It regulates entry and exit of substances in to and out of the cell. d) It can internalise solid and liquid materials by infolding or extending around them. This is the process of active intake of minerals. e) In animal cells, it is involved in adhesion, recognition and in the formation of vesicles, cilia, flagella, microvilli etc.

Golgi apparatus is absent in bacteria blue and green matches firms and red blood cells of mammals and other animals

Here, are all the statements are correct. Hence, your answer will be option [D].

Lipid molecules in the cell are synthesized by the smooth endoplasmic reticulum present in the cell.

The cell walls of adjacent cells are glued together by the plasmodesmata.

Other than nucleus mitochondria contains DNA and are able to synthesise their own proteins they are regarded as semi-autonomous organelles.

Golgi body was first discovered by Camillo Golgi. Golgi bodies, or Golgi complex are formed by stacks of flattened (saucer-shaped) membranes or flattened sacs called cisternae. Golgi bodies are usually called dictyosomes in plants. Golgi apparatus is absent in bacteria, blue-green algae, mature sperms and red blood cells of mammals and other animals. The Golgi apparatus arises from the membrane of the smooth endoplasmic reticulum, which in turn originates from the rough endoplasmic reticulum. The proximal Golgi saccules (cisternae at cis face) are formed by fusion of ER-derived vesicles, while distal saccules (cisternae at trans face) “give their all” to vesicle formation and disappear. Thus, Golgi saccules are constantly and rapidly renewed. The main functions of Golgi apparatus are (i)They store, modify, package and condense the proteins synthesised in the ribosomes. (ii)They form the cell plate during the cell division. (iii)They set aside digestive enzymes in tiny membrane bound vesicles which later become lysosomes. (iv)They synthesise some polysaccharides for the cell membrane.

Here, are all the statements are correct. Hence, your answer will be option [D].

Along with the function of secretion of various enzyme proteins and producing vacoules, Golgi apparatus is also involved in the synthesis of cell wall, plasma membrane and lysosome. Nucleus, mitochondria and plastids have their own genome (i.e., DNA) and ribosomes. They are self-replicating organelles i.e., they have power to divide and are able to synthesise their own structural protein (semi-autonomous organelles). Mitochondria is site of cellulose respiration and synthesis of energy rich compounds (ATP). Therefore, it is called as power house of the cell. The part of cell which between the plasma membrane and nuclear envelope is called the cytoplasm

Viruses are an exception to cell theory.