The Fundamental Unit of Life Test - 11

There are 26 chromosomes (13 pairs) in the cells of a frog. These chromosomes are present inside the nucleus of a cell. Chromosomes contain information for inheritance of features from parents to next generation in the form of DNA (Deoxyribo Nucleic Acid) molecules.

Protein synthesis involves formation of amino acid chain according to information present on the DNA. The ribosomes, which are present in all active cells, are the sites for the manufacture of proteins. The proteins manufactured by the ribosomes are sent to other organelles in the cell. Some proteins function as enzymes and hormones.

Mitosis is a part of the cell cycle where replicated chromosomes are separated into two new nuclei. During mitotic division, the number of chromosomes in the daughter cells remains the same. Therefore, a cell having 10 chromosomes will produce daughter cells that have 10 chromosomes each.

Genes are functional units of heredity that determines the characters of organisms.
Diffusion is the process of passage of fluid from a region of high concentration to a region of low concentration. It plays an important role in gaseous exchange between the cells as well as the cell and its external environment. Water also obeys the law of diffusion.
The passage of water from a region of higher water concentration to a region of lower water concentration through a semi-permeable membrane is called osmosis. The movement of water across the plasma membrane is affected by the amount of substance dissolved in water. 
Plasmolysis in a plant cell refers to the contraction of protoplast as a result of loss of water from the cell. The shrinkage of cytoplasm 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 the process, there is a higher external osmotic pressure and a net flow of water from the cell.

The rough Endoplasmic Reticulum (RER) has ribosomes attached to its surface. Ribosomes are the sites of protein manufacture. They are associated with the synthesis of proteins from amino acids.

Adenosine triphosphate (ATP) is called as the energy currency of the cell. Energy produced by a cell during internal respiration is stored in the form of ATP molecules. ATP breaks into ADP and phosphate to produce energy during cellular processes.

It is true that viruses are non-cellular organisms. Viruses do not contain cell membrane and other cellular organelles. Viruses are the link between the living and the non-living. They do not show any characteristics of life until they enter the body of a host. They then use the host cell machinery for reproduction.

A group of similar cells performing a specific function and having a common origin is called as tissue. Tissues form organs to perform a particular function. Organs form organ systems.

The compound microscope contains two lenses that magnify the object. It uses a lens (called the objective lens) close to the object being viewed to collect light which focuses a real image of the object inside the microscope. The image is then magnified by a second lens (called the eye piece) that gives the observer an enlarged inverted virtual image of the object.

Amoeba acquires its food by the process of endocytosis with the help of finger-like projections called pseudopodia (Pseudo means false; podia means feet). The flexibility of plasma membrane enables amoeba to use pseudopodia to engulf food and other material from its environment.