Table of contents

1. Overview of Cell Biology2h 49m
2. Chemical Components of Cells1h 14m
3. Energy1h 33m
4. DNA, Chromosomes, and Genomes2h 31m
5. DNA to RNA to Protein2h 31m
6. Proteins1h 36m
7. Gene Expression1h 42m
8. Membrane Structure1h 4m
- The Lipid Bilayer
  38m
- Membrane Proteins
  25m
9. Transport Across Membranes1h 52m
10. Anerobic Respiration1h 5m
11. Aerobic Respiration1h 11m
12. Photosynthesis52m
13. Intracellular Protein Transport2h 18m
14. Cell Signaling1h 28m
15. Cytoskeleton and Cell Movement1h 39m
16. Cell Division3h 5m
17. Meiosis and Sexual Reproduction50m
18. Cell Junctions and Tissues48m
19. Stem Cells13m
- Stem Cells
  13m
20. Cancer44m
21. The Immune System1h 6m
22. Techniques in Cell Biology1h 41m

9. Transport Across Membranes

Transporters

Cell Biology

9. Transport Across Membranes

Transporters

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Multiple Choice

How do transporters and channels select which solutes they help move across the membrane?

They only transport solutes that are hydrophobic.

They select solutes based solely on the direction of the concentration gradient.

They allow all solutes to pass through indiscriminately.

They recognize specific solutes based on size, shape, and chemical properties.

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Verified step by step guidance

Understand the role of transporters and channels: Transporters and channels are membrane proteins that facilitate the movement of specific solutes across the cell membrane. They are selective in their function, meaning they do not allow all solutes to pass through indiscriminately.

Recognize the basis of selectivity: Transporters and channels recognize solutes based on specific criteria such as size, shape, and chemical properties (e.g., charge or polarity). This ensures that only compatible solutes are transported.

Differentiate between hydrophobic and hydrophilic solutes: Hydrophobic solutes can often diffuse through the lipid bilayer without the need for transporters or channels. However, hydrophilic solutes (e.g., ions, sugars) require these proteins for transport due to their inability to pass through the hydrophobic core of the membrane.

Understand the role of concentration gradients: While the direction of the concentration gradient influences the movement of solutes (e.g., passive transport moves solutes down their gradient), it is not the sole determinant of selectivity. The structural and chemical compatibility of the solute with the transporter or channel is critical.

Conclude with the correct answer: Transporters and channels select solutes based on their size, shape, and chemical properties, ensuring specificity in the transport process and maintaining cellular homeostasis.