Problem 96 - Objective Biology for NEET

Question

In which kind of transport, the molecules will go against the concentration gradient? (a) Passive transport (b) Active transport (c) Facilitated transport (d) All of these

Step-by-Step Solution

Answer

The molecules will go against the concentration gradient in Active transport.

Step 1: Understanding the types of transport

There are three types of cellular transport including Passive transport, Active transport, and Facilitated transport.

Step 2: Identifying the type of transport against the concentration gradient

In the case of Passive transport and Facilitated transport, molecules move from a region of higher concentration to the region of lower concentration, i.e., along the concentration gradient. Active transport, on the other hand, is the only type where molecules move from an area of lower concentration to an area of higher concentration, i.e., against the concentration gradient, with the help of energy in the form of ATP.

Step 3: Answer determination

Given this, the type of transport where molecules will go against the concentration gradient is Active transport.

Key Concepts

Active Transport

Active transport is a cellular process where molecules move against their concentration gradient. This means they move from a region of low concentration to a region of high concentration. Unlike passive transport, active transport requires energy. This energy comes from ATP, a molecule that stores and provides energy for many cellular functions. Here are some key points about active transport:

• Energy-dependent: It needs ATP to go against the natural flow of molecules.
• Examples include the sodium-potassium pump and proton pumps.
• Helps maintain cell potential and internal concentrations of ions.

Active transport is crucial for cells to maintain homeostasis, enabling them to import nutrients and export waste efficiently.

Concentration Gradient

A concentration gradient refers to the difference in the concentration of a substance between two areas. In cellular biology, this concept commonly relates to the distribution of ions and molecules inside and outside of cells. The concentration gradient acts as a driving force for certain types of cellular transport processes.
A few things to remember about concentration gradients:

• They dictate the direction in which molecules tend to move (from high to low concentration).
• They are essential for processes like diffusion and osmosis.
• Creating and maintaining gradients is energy-intensive, especially in active transport.

The concentration gradient is a fundamental concept for understanding how substances move in and out of cells, impacting cellular functions and overall organism health.

Facilitated Transport

Facilitated transport, sometimes known as facilitated diffusion, is a special type of passive transport. It allows substances to move across cell membranes with the help of carrier proteins. While it does not require energy, it is essential for transporting molecules that cannot easily pass through the lipid bilayer.
Points to consider for facilitated transport:

• It's passive, meaning it doesn't require cellular energy.
• Molecules move along the concentration gradient.
• Transport proteins, like channels or carriers, are involved.

This method is vital for cells, especially for the uptake of materials like glucose and ions that need assistance to travel across the membrane.

Passive Transport

Passive transport is the process by which molecules move across the cell membrane without the use of energy. It relies on the concentration gradient, with molecules moving from areas of high concentration to areas of low concentration.
Key features of passive transport include:

• No energy required: Molecules move naturally along the gradient.
• Includes diffusion, osmosis, and simple diffusion.
• Maintains equilibrium on both sides of the membrane.

Passive transport is crucial for maintaining cell homeostasis and allowing substances like water and gases to readily pass in and out of cells without expending energy.