/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 37 Why is it difficult for ions to ... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 22: Problem 37

Why is it difficult for ions to diffuse across cell membranes?

Short Answer

Expert verified
Answer: It is difficult for ions to diffuse across cell membranes due to the hydrophobic interior of the phospholipid bilayer, which creates an energetically unfavorable environment for charged particles, and the selective control of ion movement by specialized membrane proteins, which allow only specific ions to pass through. Both of these factors contribute to maintaining a regulated balance of ions inside and outside the cell.

Step by step solution

01

Understand the structure of cell membranes

Cell membranes are composed mainly of lipid molecules called phospholipids. These phospholipid molecules arrange themselves into a bilayer, forming a barrier that separates the inside of the cell from the external environment. The bilayer is made of two layers of phospholipids, with their hydrophilic (water-loving) heads pointing outwards and their hydrophobic (water-fearing) tails pointing inwards.
02

Consider the properties of ions

Ions are charged particles, formed when atoms gain or lose electrons. For example, sodium (Na+) and chloride (Cl-) ions are formed when sodium chloride (common table salt) dissolves in water. Ions are typically quite small, but their charge greatly impacts their interactions with other molecules.
03

Recognize the role of the hydrophobic interior

The hydrophobic interior of the cell membrane presents a significant barrier for the diffusion of ions. Due to their charged nature, ions are attracted to polar (water-loving) environments and repelled by nonpolar (hydrophobic) environments. The hydrophobic region of the membrane creates an energetically unfavorable environment for ions, making it difficult for them to passively diffuse across the cell membrane.
04

Understand the importance of membrane proteins

Some ions can cross the cell membrane with the help of specialized proteins embedded within the phospholipid bilayer. These proteins, called ion channels, allow specific ions to pass through while excluding others, thus maintaining a controlled ion movement across the membrane. These channels are selective, based on factors such as ion size, charge, and concentration. Some channels have gates that can open or close based on cell signals or changes in membrane voltage.
05

Conclusion

In summary, ions have difficulty diffusing across cell membranes due to 1) the hydrophobic interior of the phospholipid bilayer, which creates an energetically unfavorable environment for charged particles, and 2) the selective control of ion movement by specialized membrane proteins, which allow only specific ions to pass through. Both of these factors contribute to keeping a regulated balance of ions inside and outside the cell.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Ion Transport in Cells Describe three ways in which ions of major essential elements (such as \(\mathrm{Na}^{+}\) and \(\mathrm{K}^{+}\) ) enter and exit cells.

Place the following ions in order of increasing ionic radius: \(\mathrm{Mg}^{2+}, \mathrm{Li}^{+}, \mathrm{Al}^{3+},\) and \(\mathrm{Cl}^{-}.\)

Which of the following cannot be measured: ionization energy, electron affinity, ionic radius, atomic radius, or electronegativity?

Algae in the genus Closterium contain structures built from barium sulfate (barite). Calculate the solubility in moles per liter of \(\mathrm{BaSO}_{4}\) in water at \(25^{\circ} \mathrm{C}\) given that \(K_{\mathrm{sp}}=1.08 \times 10^{-10}.\)

Helium is used in scuba gear to prevent nitrogen narcosis. Do you expect the solubility of He in blood to be greater than or less than the solubility of Xe and Ar in blood?
See all solutions

Recommended explanations on Chemistry Textbooks

Kinetics

Read Explanation

Chemistry Branches

Read Explanation

The Earths Atmosphere

Read Explanation

Organic Chemistry

Read Explanation

Inorganic Chemistry

Read Explanation

Physical Chemistry

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.