The Fundamental Unit of Life Test - 12

Mycoplasma gallisepticum is the smallest cell amongst the unicellular organisms. Acetabularia measures nearly 10 cm in height. Tonoplast is the membrane which bounds the chief vacuole of a plant cell. It is also known as the 'vacuolar membrane'. It separates the vacuolar contents from the cytoplasm of the cell. Root tips are replaced; they are meristematic tissue; and not permanent tissue.

While the nucleic part of the cell had been observed by Leeuwenhoek in 1682, it was Robert Brown who named it the “cell nucleus”. In 1839, Johann Evangelist Purkinje coined the term 'protoplasm' for the fluid substance of a cell. Robert Hooke observed the microscopic structure of the bark of a cork tree and in doing so, discovered and named the cell – the building block of life. The 'Cell theory' was proposed by Matthias Jakob Schleiden and Theodor Schwann.

Shrinkage of cell occurs due to exo-osmosis in a hypertonic medium. A hypertonic solution is one which has a lesser concentration of water as compared to that inside the cell. During exo-osmosis, there is a higher external osmotic pressure and a net flow of water from the cell. Swelling of cells occurs due to endo-osmosis. The inward flow of water into the cell containing an aqueous solution through a semi-permeable membrane is called as endo-osmosis. Nucleus is the organelle that control all the activities of a cell. Plant cells have large-sized vacuoles.

Mitochondria iscalled as power house of the cell because it contains enzymes for cellular respiration. During cellular respiration, energy is released which is stored in the form of ATP.

The full form of ATP is adenosine triphosphate. ATP is known as the energy currency of the cell. The energy required for various chemical activities is released by mitochondria. They contain enzymes for cellular respiration.

Mitochondria are called the powerhouses of the cell. The energy required for various chemical activities is released by mitochondria. They contain enzymes for cellular respiration. During cellular respiration, energy is released in the form of ATP (Adenosine triphosphate). The body uses energy stored in ATP.

Plant cells have plastids. Plastids with coloured pigments impart colours to various plant parts. Green colour is provided by chloroplast and other colours (except white) are imparted by chromoplast.

Both the statements are correct. Golgi apparatus consists of a system of membrane-bound vesicles. The proteins manufactured by the ribosomes are packed inside the vesicles. Endoplasmic Reticulum (ER) is absent in the red blood cells of mammals. Red Blood Cells in mammals anucleate when mature i.e. they do not contain a nucleus. This is so that the cell has maximum space for haemoglobin.

Cell-wall is a non-living part of the cell. It is made up of cellulose. 
Mitochondria are called the powerhouses of the cell. The energy required for various chemical activities is released by mitochondria. They contain enzymes for cellular respiration.
Ribosomes are associated with the synthesis of proteins from amino acids. Proteins are required by a cell for functions such as repair or directing chemical processes.
Chloroplasts are found in leaves of plants. They make use of sunlight to perform a process called photosynthesis.

Cells are enclosed by a plasma membrane composed of proteins and lipids. It separates the contents of the cell from the external environment. It permits entry of selective substances in the cell. It allows exit of selective substances from the cell. 
Tonoplast is the membrane which bounds the chief vacuole of a plant cell. It is also known as the vacuolar membrane. It separates the vacuolar contents from the cytoplasm of the cell.
Stroma is the ground material of chloroplast. It is the part of a tissue or an organ that has a connective and structural role. 
Each of the partial partitions in a mitochondrion formed by infolding of the inner membrane is known as Cristae.