The Fundamental Unit of Life Test - 27

Correct Option: D
Explanation:

• A large central vacuole is a characteristic of a plant cell. 
• It is a membrane-bound organelle.
• The plant cell vacuole is filled with water and excretory substances.

If a cell swells after been placed in a solution, it means water from solution has entered the cell. As water flows from a region of its own higher concentration to a region of lower concentration, we conclude that water is present in higher concentration in the solution as compared to the cell sap. Thus, the solution is hypotonic as compared to cell sap. The process in which water enters the cell is called as endosmosis.

If a cell is reduced in size i.e., shrinks on placing in a solution of sugar, it means the solvent present in the cell moves out from the cell. Thus, the outer solution has more concentration of solute than the cell i.e., The sugar solution is a hypertonic solution.

The nucleus is the most important and the largest component of the cell. Nucleus regulates the four main functions of the cell which are protein synthesis, cell division, growth and differentiation are carried out by the nucleus. Nucleus regulates all these cellular activities by controlling the enzymes required for cellular processes. Enzymes are proteins and protein synthesis is controlled by nucleus as mRNA required for protein synthesis is made from DNA which is situated in the nucleus.

• A group of cells that are similar in structure and work together to achieve a particular function forms a tissue.
• There are four basic tissue types present in animals defined by their morphology and function: epithelial tissue, connective tissue, muscle tissue, and nervous tissue.

So the correct answer is option C.

Solution

Correct answer is option A.

Explanation for correct option:

• Absorption of water refers to translocation of water from soil solution to xylem of root.
• Root hairs collect water and mineral nutrients that are present in the soil and take this solution up through the roots to the rest of the plant.
• The osmosis of water occurs in the root hair due to the presence of a high concentration of solutes in the cell sap.

• A small cell has less volume than a larger cell and so the enzymes, proteins are able to work faster due to surface area: volume ratio. 
• This causes things to move around a lot quicker in smaller cells than in larger cells and so are metabolically more active.
• Thus the correct answer is option C.