$A, B, C$ and $D$ are the basic part of all the cells. The part $A$ contains threadlike structures called $E$ which transfer the characteristic from parents to their off springs. The part $B$ uses glucose and oxygen to produce energy whereas part $C$ controls the movement of substance into the cell. The part $D$ is a transparent, jelly-like material. What could $A, B, C, D$ and $E$ be$?$
Answer
$A$ is nucleus; $B$ is mitochondria; $C$ is cell membrane; $D$ is cytoplasm; and $E$ is chromosomes.
$X$ and $Y$ are the two types of cells. The cells $X$ have a well$-$organized nucleus which is separated from the cytoplasm by the nuclear membrane on the other hand, cells $Y$ do not have a real nucleus, their nuclear material is in direct contact with the cytoplasm.
$a.$ What type of cells are $(i)\ X,$ and $(ii)\ Y?$
$b.$ Give one example each of cells like $(i)\ X,$ and $(ii)\ Y?$
Name two cells which are found in animals and two which are found in plants.
Answer
The cells which are found in animals are – Red blood cells $(RBCs)$ and Muscle cells The cells which are found in plants are – Xylem cells and phloem cells.
Why are plant and animal specimens usually stained with dyes before observing them through a microscope? Name one stain (or dye) used for this purpose.
Answer
The various parts of the cell are colorless and hence, difficult to distinguish. So, various stains are used to colour the parts of the cell to study the detailed structure through a microscope. The dyes (stains) which are used in the study of cell structure are methylene blue, dilute iodine solution, etc.
What is the shape of red blood cells in human blood? What function do red blood cells perform?
Answer
Red blood cells $(RBCs)$ are usually spherical in shape. The main function of red blood cells is to carry oxygen from the lungs to the tissues around the body.
Gene is a unit of inheritance in living organisms. It controls the transfer of a hereditary characteristic from parents to offspring. Genes are located on chromosomes.
Nerve cells (neurons) are long, branched and have thread-like projections so that they can connect other nerves cells and transmit messages over long distance.