Our Secret Universe The Hidden Life of the Cell
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Explanation:
B) protein channel
Lipids are composed of fatty acids which form the hydrobic tail and glycerol which forms the hydrophilic head; glycerol is a 3-Carbon alcohol which is water soluble, while the fatty acid tail is a long chain hydrocarbon (hydrogens attached to a carbon backone) with up to 36 carbons.
Their polarity or arrangement can give these non-polar macromolecules hydrophilic and hydrophobic properties. Via <em>diffusion,</em> small water molecules can move across the phospholipid bilayer acts as a semi-permeable membrane into the extracellular fluid or the cytoplasm which are both hydrophilic and contain large concentrations of polar water molecules or other water-soluble compounds. The hydrophilic heads of the bilayer are attracted to water while their water-repellent hydrophobic tails face towards each other- allowing molecules of water to diffuse across the membrane along the concentration gradient.
Transmembrane proteins are embedded within the membrane from the extracellular fluid to the cytoplasm, and are sometimes attached to glycoproteins (proteins attached to carbohydrates) which function as cell surface markers. Carrier proteins and channel proteins are the two major classes of membrane transport proteins.
- Carrier proteins (also called carriers, permeases, or transporters) bind the specific solute to be transported and undergo a series of conformational changes to transfer the bound solute across the membrane. Transport proteins spanning the plasma membrane facilitate the movement of ions and other complex, polar molecules which are typically prevented from moving across the membrane.
- Channel proteins which are pores filled with water versus enabling charged molecules to diffuse across the membrane, from regions of high concentration to regions of lower concentration. This is a passive part of facilitated diffusion
Learn more about membrane components at brainly.com/question/1971706
Learn more about plasma membrane transport at brainly.com/question/11410881
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