Class 9 Science Chapter 5 MCQ

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

The Golgi apparatus is involved in formation of lysosome. Lysosomes are simple, tiny spherical sac-like structures evenly distributed in the cytoplasm each lysosome is surrounded by a double membrane and contains powerful enzymes capable of digesting or breaking down all organic material. These enzymes are made by rough endoplasmic reticulum. They perform following functions in our body: i)They help in breaking down or digesting large molecules of the cell. ii)They help in a defence against bacteria and viruses. iii)During starvation, lysosomes act on their own cellular organelles and digest them. This results in cell death. The lysosomes are also called suicide bags or demolition squads of the cell.

Generally, inside the cell there exist a membranous network enclosing a fluid-filled lumen which almost fills up the intracellular cavity, called endoplasmic reticulum (ER). It is of two types: i)Rough Endoplasmic Reticulum with ribosomes attached on its surface for synthesizing proteins. Ii)Smooth Endoplasmic Reticulum which is without ribosome and is meant for secreting lipids.

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

Endocytosis is the ingestion of material by the cells through their plasma membrane. It is a collective term that describes three similar processes “phagocytosis” (cell eating), “potocytosis” (cell drinking) and receptor-mediated endocytosis. These processes are pathways to specifically internalise solid particles, small molecules and ion, and macromolecules, respectively. All of them require energy, so they may be regarded as different forms of active transport. Out of these phagocytosis is the common method of feeding among the Protozoa (e.g., Amoeba) and lower “Metazoa” (e.g., sponges). In pseudopodial movement the phagocyte enguls the particle lysosomes, join with the vacoule containing ingested particle and pour their contents into the vacoule to destroy the particle.

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

The volume of a cell is fairly constant for a particular cell type and is dependent to the size of an organism. For example, kidney or liver cells are approximately the same size in a bull, horse and mouse. The difference in the total mass of the organ or organisms dependent on the number, not on the volume of the cells. The cells of an elephant are not necessarily larger than those of other tiny animals or plants. The large size of an element is due to the larger number of cells present in its body.

The prokaryotic cells lack true nucleus and a circular DNA lies naked in the cytoplasm. The unidentified nuclear region of the cell is called nucleoid. The prokaryotic cell lacks chromosomes and nucleolus or nuclear membrane and nucleoplasm remains undifferentiated from the cytoplasm.

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

Osmosis is a spontaneous process where movement of solvent molecules occurs into a region of higher solute concentration from lower solute concentration through a partially permeable membrane, so as to tend to equalise the solute concentration on the two sides. When movement of the solvent takes place from outside to inside the all (inward movement) the process is endosmosis. It occurs in hypertonic solution and causes the swelling of cell. When the movement of solvent takes place from inside to outside of the cell (outward movement) the process is exosmosis. It occurs in hypertonic solution. It results the shrinkage of the cell. When the concentration of water both in the surrounding medium and in the cell is same, the solution in the surrounding medium is said to be isotonic and no movement of water molecules takes place.