Main Answer
Active transport through simple diffusion is an example of Active transport across a membrane.The correct option is A)Active transport.
Explanation
Passive transport refers to the movement of molecules or ions across a cell membrane without the expenditure of energy. There are several types of passive transport, including simple diffusion, facilitated diffusion, and osmosis. In this explanation, we will focus on simple diffusion as an example of passive transport.
Simple diffusion is the movement of molecules or ions from an area of higher concentration to an area of lower concentration until equilibrium is reached. This type of passive transport does not require any energy input, as the molecules or ions move down their concentration gradient.
Simple diffusion occurs through small gaps in the cell membrane called lipid bilayers, which are made up of phospholipids and cholesterol. These lipid bilayers are selectively permeable, meaning that they allow certain molecules or ions to pass through while preventing others from doing so.
In simple diffusion, molecules or ions move across the membrane by randomly colliding with the lipid bilayer until they diffuse through it. The rate of simple diffusion is determined by several factors, including the size and charge of the molecule or ion, the concentration gradient, and the thickness and composition of the membrane.
Generally, smaller, uncharged molecules diffuse more quickly than larger, charged molecules due to their smaller size and lack of repulsion from the membrane.
Simple diffusion is important for maintaining homeostasis within cells and organisms. It allows for the constant movement of nutrients, waste products, and other molecules across cell membranes to maintain a balance between the inside and outside of cells.
Without simple diffusion, cells would become imbalanced and unable to function properly.
In summary, simple diffusion is an example of passive transport across a membrane because it does not require any energy input and occurs through selectively permeable membranes due to concentration gradients.
This type of passive transport is important for maintaining homeostasis within cells and organisms by allowing for the constant movement of molecules across cell membranes.The correct option is A)Active transport.