Table of contents

1. Introduction to Microbiology3h 22m
2. Disproving Spontaneous Generation1h 18m
3. Chemical Principles of Microbiology3h 38m
4. Water1h 28m
5. Molecules of Microbiology2h 23m
6. Cell Membrane & Transport3h 28m
7. Prokaryotic Cell Structures & Functions5h 52m
8. Eukaryotic Cell Structures & Functions2h 18m
9. Microscopes2h 46m
10. Dynamics of Microbial Growth4h 36m
11. Controlling Microbial Growth4h 10m
12. Microbial Metabolism5h 16m
13. Photosynthesis2h 31m
14. DNA Replication2h 25m
15. Central Dogma & Gene Regulation7h 14m
16. Microbial Genetics4h 44m
17. Biotechnology3h 0m
18. Viruses, Viroids, & Prions4h 56m
19. Innate Immunity7h 15m
20. Adaptive Immunity7h 14m
21. Principles of Disease6h 57m

6. Cell Membrane & Transport

Simple and Facilitated Diffusion

Microbiology

6. Cell Membrane & Transport

Simple and Facilitated Diffusion

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Multiple Choice

Which type(s) of molecules cannot enter/exit the cell via simple diffusion and require facilitated diffusion?

Nonpolar oxygen gas molecules.

Charged Ca²⁺ ions

Nonpolar carbon dioxide gas molecules.

Nonpolar water molecules

Charged Na⁺ ions

b and e only

a, c, and d only

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Verified step by step guidance

Understand the concept of simple diffusion: Simple diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration without the need for energy or assistance from transport proteins. It typically involves small, nonpolar molecules.

Identify the characteristics of molecules that can pass through the cell membrane via simple diffusion: Nonpolar and small molecules, such as oxygen (O2) and carbon dioxide (CO2), can easily diffuse across the lipid bilayer of the cell membrane.

Recognize the role of facilitated diffusion: Facilitated diffusion is a process that allows molecules that cannot directly diffuse through the cell membrane to pass through with the help of transport proteins. This process is necessary for polar or charged molecules.

Analyze the given molecules: Nonpolar oxygen gas (O2) and carbon dioxide gas (CO2) can diffuse through the membrane via simple diffusion. Water molecules, although polar, can also pass through the membrane due to their small size, often through specialized channels called aquaporins.

Determine which molecules require facilitated diffusion: Charged ions like Ca2+ and Na+ cannot pass through the hydrophobic lipid bilayer without assistance. They require transport proteins to facilitate their movement across the cell membrane, thus needing facilitated diffusion.