Tag: osmosis and plasmolysis

In cellular biology, active transport is the movement of molecules across a membrane from a region of their lower concentration to a region of their higher concentration—against the concentration gradient. Active transport requires cellular energy to achieve this movement. There are two types of active transport: primary active transport that uses ATP, and secondary active transport that uses an electrochemical gradient. An example of active transport in human physiology is the uptake of glucose in the intestines. So substances like glucose, amino acids, sodium ions in filtrate are reabsorbed by active transport.

Minerals are absorbed from the soil in the form of ions. Absorption of minerals and water are two different processes but the  pathway is same. Mineral ions cannot be absorbed by osmosis or diffusion because the concentration is low. So the root hair cells have carrier molecules on their surface which pick the ions and move against the concentration gradient. Since the movement is against the concentration gradient then ATP will be required. So The absorption of ion is a Active process. 

The sodium-potassium pump is a specialized mechanism to transport proteins using energy. The process of moving sodium and potassium ions across the cell membrane is an active transport as it involves the hydrolysis of ATP. The hydrolysis of ATP molecule provides the necessary energy for the transport of molecules across the membrane. The action involves an enzyme known as Na+/K+-ATPase.

Lines of stomates (shown by the orange colour of the guard cells) lie along the flanks describe the status and movement of water in plants, soil and the atmosphere. This internal hydrostatic pressure (also called turgor pressure) is typically 0.5 away from the cell wall, and solution with small molecular weight solutes. 

• After dipping into water wilted vegetable regain their size, as water travells through a network of veins through out the plant and cell are hydrated and refirm their size. by a process called osmosis .
• Leaves turn yellow or red when they falls , in fallpalnt breakdown and reabsorb chlorophyll, letting the colours of other pigments show through , hence colour changes.
• When vegitables are wilted due to  dehydration, their size decreases due to loss of water.
  

Sodium-potassium pump is important to produce action potential by nerve cells. As it transport of three Na+ to the outside of the cell and the transport of two K+ ions to the inside. This changes the membrane potential on the inside, making the inside of the cell more negative or hyperpolarized, which leads to forward movement of electric impulse

 It is called water absorption 'through roots', rather 'by' roots. It occurs in rapidly transpiring plants during the daytime, because of the opening of stomata and the atmospheric conditions. The force for absorption of water is created at the leaf end i.e. the transpiration pull.

There are two types of absorption mechanisms i.e., active and passive transport. Active transport is the movement of solute or solvent molecules against the concentration gradient. It requires the expenditure of energy in the form of ATP. Thus, the correct answer is option B.

In active transport, substances move against a concentration gradient across a cell membrane. Hence energy is required. The energy available in the body in the form of ATP is used to move this substance across the cell membrane. Thus the correct answer is option C.