Lakhmir Singh & Manjit Kaur Test: The Fundamental Unit of Life - Class 9 MCQ

Cell wall - Plant Cells
Power house of cell - Mitochondria
Photosynthesis - Chloroplast
Protein synthesis  Ribosomes

Functional segments of DNA are called genes.

Mitochondria are called as power house of the cell because it contain enzymes for cellular respiration in which energy is released in form of ATP.

• Distinct nucleus: Eukaryotic cells have a well-defined nucleus that contains the cell's genetic material.
• Nucleolus: This is a small structure within the nucleus, responsible for ribosome production.
• Nuclear membrane: Eukaryotic cells possess a nuclear membrane that encloses the nucleus, separating it from the cytoplasm.

R. Virchow in 1855 presented the idea that all cells arise from pre-existing cells. This was modification in the earlier cell theory.

Prokaryotes lack nucleus and thus they are called nucleoid. 
Eukaryotes contain nucleus and thus they are referred as complete cell. 
Viruses act both as living and non- living. 
Peroxisomes helps in removal of toxic substances.

Animal cell that do not contain nuclei also lack in chromosome. As chromosome is present in the nucleus of the cell.

The full form of ATP is adenosine tri phosphate. It is known as energy currency of the cell.

The passage of water from a region of higher water concentration to lower concentration through a semi-permeable membrane is called osmosis.

Protoplasm is fluid sbstance in a cell because it comprises the living part of the cell including the cytoplasm, nucleus and other organelles and carries out all the processes necessary for life, like processing nutrients and oxygen, converting food into living matter, throwing out of used substances, producing new cells etc.

Ribosomes are primary site of protein synthesis or translation and measure 20 nm.
Lysosomes or "suicidal bags" of the cell measure 200 nm.
Mitochondria, the powerhouse of the cell are site of cellular respiration measures 3000 nm
Chloroplast is the site of photosynthesis and measures 5000 nm.
Therefore, ribosomes are smallest of all.
 

Mitochondria are called the power house of the cell because it contain enzyme for cellular respiration in which energy is released in form of ATP

- Root hair cells absorb water primarily through osmosis.
- Osmosis is the movement of water molecules from a region of higher water potential (soil) to a region of lower water potential (root hair cells) through a selectively permeable membrane.
- Soil water has a higher water potential than the root hair cells due to dissolved solutes in the cell sap.
- This passive process does not require energy, making it efficient for plants to absorb the necessary water for survival.

The term protoplasm was coined by J.E Purkinje. Protoplasm is the fluid medium in which different cell organelles are present.

The correct option is Option C.
In 1831, while investigating the fertilization mechanisms of plants in the Orchidaceae and Asclepiadaceae families, he noted the existence of a structure within the cells of orchids, as well as many other plants, that he termed the “nucleus” of the cell.
Johann Evangelist Purkinje) (17 or 18 December 1787 – 28 July 1869) was a Czech anatomist and physiologist. In 1839, he coined the term 'protoplasm' for the fluid substance of a cell. He was one of the best known scientists of his time.
The cell was first discovered by Robert Hooke in 1665, which can be found to be described in his book Micrographia. In this book, he gave 60 'observations' in detail of various objects under a coarse, compound microscope. One observation was from very thin slices of bottle cork.
By the late 1830s, botanist Matthias Schleiden and zoologist Theodor Schwann were studying tissues and proposed the unified cell theory. The unified cell theory states that: all living things are composed of one or more cells; the cell is the basic unit of life; and new cells arise from existing cells.
 

Protein synthesis involve formation of amino acid chain according to information present on DNA. Ribosomes provide site for protein synthesis.

Lysosome is called as the suicide bag of the cell as it contain enzymes for hydrolysis of all cell components in case of injury.

In the primary (growing) plant cell wall, the major carbohydrates are cellulose, hemicellulose and pectin. The cellulose microfibrils are linked via hemicellulosic tethers to form the cellulose-hemicellulose network, which is embedded in the pectin matrix.
 

Lysosomes present in the cytoplasm of cell contain very strong enzymes that can breakdown the all organic wastes produced in the cell. So, lysosome is called as garbage disposal system of the cell.