Final answer:
Active transport is the mechanism that moves molecules against their concentration gradient, requiring energy typically sourced from ATP and specific transport proteins such as pumps. Malfunction of these proteins can disrupt cell functions and cause diseases. Factors affecting membrane transport include concentration gradients, electric charge differences, and lipid solubility.
Step-by-step explanation:
Understanding Transport Mechanisms in Cells
The transport mechanism involved in the movement of molecules against their concentration gradient is known as active transport. This process requires energy, usually in the form of ATP (adenosine triphosphate), to move molecules from an area of lower concentration to an area of higher concentration. There are specific transport proteins, such as pumps, involved in this process, for instance, the sodium-potassium pump.
Active transport helps maintain essential concentration gradients within the cell. For example, the sodium-potassium pump maintains the electrochemical gradient necessary for nerve impulse conduction. When these transport proteins malfunction, it can lead to a failure in maintaining ion balances, disrupting cell function, which might result in conditions like cystic fibrosis or neurological disorders due to imbalances in neurotransmitter substance transport.
Factors that affect the movement of materials across a membrane include the concentration gradient, the electric charge difference (electrical gradient), and the membrane's lipid solubility. A concentration gradient drives diffusion; the more significant the difference, the faster the diffusion rate. The electrical gradient can either promote or hinder the movement of charged particles, while the membrane's lipid solubility affects the ease with which lipid-soluble molecules pass through.
Vesicle transport is another form of active transport used for very large molecules, such as proteins, which cannot pass through the plasma membrane on their own. It includes processes like endocytosis and exocytosis, which involve the formation of vesicles that envelop substances to move them in or out of the cell.