Question

Compare and contrast the following:a. Simple diffusion and facilitated diffusionb. Active transport and facilitated diffusionc. Active transport and group translocation

Accepted Answer

Step 1: Define simple diffusion and facilitated diffusion. Simple diffusion is the passive movement of molecules from an area of higher concentration to an area of lower concentration directly through the phospholipid bilayer without the assistance of membrane proteins. Facilitated diffusion also moves molecules down their concentration gradient but requires specific carrier or channel proteins to help molecules that cannot easily cross the membrane on their own. Step 2: Compare simple diffusion and facilitated diffusion by focusing on their mechanisms and specificity. Simple diffusion is non-specific and occurs for small, nonpolar molecules, while facilitated diffusion is specific to certain molecules and involves protein channels or carriers. Both processes do not require energy and move substances down their concentration gradients. Step 3: Define active transport and facilitated diffusion. Active transport is the movement of molecules against their concentration gradient, from lower to higher concentration, using energy usually derived from ATP. Facilitated diffusion, as mentioned, moves molecules down their concentration gradient without energy input, using membrane proteins. Step 4: Contrast active transport and facilitated diffusion by emphasizing energy use and direction of movement. Active transport requires energy and can move substances against their gradient, while facilitated diffusion does not require energy and only moves substances down their gradient. Both use membrane proteins but differ in energy dependence and directionality. Step 5: Define group translocation and compare it with active transport. Group translocation is a type of active transport where the transported molecule is chemically modified during its passage across the membrane, often by phosphorylation, which helps retain the molecule inside the cell and prevents it from diffusing back out. Active transport generally moves molecules without chemically altering them. Both require energy and move substances against their concentration gradients.

Compare and contrast the following:
a. Simple diffusion and facilitated diffusion
b. Active transport and facilitated diffusion
c. Active transport and group translocation

비슷한 문제에 대한 검증된 영상 답변:

주요 개념

Simple Diffusion

Facilitated Diffusion

Active Transport and Group Translocation