Practice MCQ Questions and answers on Biology-GK

Salts and sugars work to preserve foods by creating a hypertonic environment.

During active transport, substances move against the concentration gradient, from an area of low concentration to an area of high concentration. This process is “active” because it requires the use of energy (usually in the form of ATP). It is the opposite of passive transport.

N.S. Parihar proposed a theory for long distance transport of water in plants.

Primary active transport moves ions across a membrane and creates a difference in charge across that membrane. The primary active transport system uses ATP to move a substance, such as an ion, into the cell, and often at the same time, a second substance is moved out of the cell.

Passive transport requires no energy from the cell. Examples include the diffusion of oxygen and carbon dioxide, osmosis of water, and facilitated diffusion.

Oxygen crosses a plasma membrane by diffusion.

Option A: It is a type of diffusion
Osmosis is indeed a special type of diffusion.
Diffusion is the movement of particles from an area of high concentration to an area of low concentration.
Osmosis is specifically the diffusion of water across a semi-permeable membrane.
So, this statement is TRUE.

Option B: Movement is against water's concentration gradient
Osmosis involves water moving from an area of high water concentration to an area of low water concentration.
This means it moves down the concentration gradient, not against it.
So, this statement is FALSE.

Option C: Requires energy
Osmosis is a passive process.
Passive processes don't require the cell to expend any energy (like ATP).
The movement of water is driven by the difference in water concentration.
So, this statement is FALSE.

Option D: All of the above
Since not all the options are true, this statement is FALSE.

Therefore, the correct answer is A: It is a type of diffusion

Capillary water is the water held by micropores of soil. This water is available for the plant because it gets trap in soil solution near the root of the plants. And some water is retained in mineral salts by chemical bonds but it does not increase the absorption capacity of roots. This is called chemically combined water. Thus the only water available for the plant is capillary water so the correct option is C.

The process of evaporation occurs from leaf.

In cellular biology, active transport is the movement of molecules across a cell membrane from a region of lower concentration to a region of higher concentration—against the concentration gradient. Active transport requires cellular energy to achieve this movement.