PART 3: DIFFUSION VS. FACILITATED DIFFUSION VS. ACTIVE TRANSPORT \"The most obvi

Question

PART 3: DIFFUSION VS. FACILITATED DIFFUSION VS. ACTIVE TRANSPORT "The most obvious thing one notices about E. coli is that one can notice E. coli at all."Microcosm: E. Coli and the New Science of Life, by Carl Zimmer. racllular space channel E. coli is not a microscopic bal- loon, filled with gas and goo. E. coli, and other microbes are a densely "stuffed package" filled with the molecules needed for sustaining life. Carrier ... protein Intracellular space There is a clear boundary with an INSIDE and an OUTSIDE. For a single celled organism this boundary is the cell membrane, the cell wall, or a combination of both. This boundary has many functions, it defines the outer limit of an entire organism, it allows for the sequestration of the millions of molecules that make up E. coli to remain together instead of quickly dispersing out into the environment. Without the cell membrane, organisms could not exist. However, life also needs to remain connected to the OUTSIDE. Molecules must enter and molecules must exit. Without movement from the INSIDE to the OUTSIDE and vice versa, the cell membrane becomes a tomb. Evolution has solved this problem with the appearance of channels that connect the INSIDE to the OUTSIDE. These channels come in every shape and size, and can be highly regulated. 1. All cells acquire the molecules and ions they need from the environment. There are two problems to solve when dealing with moving molecules across a membrane: #1. Concentration: Molecules and ions tend to move spontaneously down their concentra- tion gradients. What is this process called? #2. Many of the molecules the cell needs to move from the outside in will already be at a higher concentration inside the cell concentration gradient, a process that requires energy. What is this process called? . The cell needs to move these molecules against their

Explanation / Answer

1- When the molecules move down their concentration gradients the process is called as passive transport. This process continues till there is concentration equilibrium between both the sides means both the sides have same concentration.

2- The process is called is active transport as it need ATP or energy to moves the molecules against its concentration gradient.

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