Class 9 Science Chapter 5 MCQ

Grana are stacks of membrane bounded flattened discoid sacs containing the molecules of chlorophyll.

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

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.

Chloroplasts are present in green algae and higher plants. They have a green pigment called chlorophyll and they are involved in the photosynthesis of food. Therefore, they are also known as the ‘kitchens of the cells’. Each chloroplast is bounded by two-unit membranes like the mitochondria. It shows two distinct regions: i)Grana are the main functional units of chloroplast. They are stacks of membrane bounded, flattened discoid sacs (called thylakoids) containing the molecules of chlorophyll. ii)Stroma is the homogeneous matrix in which grana are embedded. It contains a large variety of photosynthetic enzymes, starch grains DNA and ribosomes.

Camillo Golgi, discovered the revolutionary method of staining individual cell structures. This method is referred to as “Black reaction”. It uses weak solution of silver nitrate and is valuable in tracing the processes and most delicate ramifications of cells.

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

Plasma membrane is present in cells of plants, animals and microorganisms.

The endoplasmic reticulum performs the following functions: (i)It increases the surface area of the cytoplasm for various metabolic activities of the cell. (ii)It gives internal support to the colloidal matrix i.e., cytoplasm. (ii)It is associated with the synthesis, storage and transport of metabolic products. (iv)It helps in the formation of the cell plate and nuclear membrane during cell division. (v)Routh Endoplasmic Reticulum (RER) is associated with the synthesis of proteins. (iv)Smooth Endoplasmic Reticulum (SER) secretes lipids which along with proteins constitute cell membrane by a process called membrane biogenesis.

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

Ribosomes are dense, spherical and granular particles which remains freely in the matrix or remain attached to endoplasmic reticulum. They are not bound by membrane and are present in both prokaryotic and eukaryotic cells. They play important role in synthesis of proteins. All enzymes are proteins but all hormones are not proteins.