4.2) Diffusion Flashcards

1
Q

What is diffusion?

A

The net movement of molecules or ions from a region where they are more highly concentrated to one where their concentration is lower until evenly distributed.

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2
Q

What type of transport is diffusion classified as?

A

Passive transport.

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3
Q

What does ‘passive’ mean in the context of diffusion?

A

Energy comes from the natural, inbuilt motion of particles, rather than from some external source such as ATP.

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4
Q

What affects the rate of diffusion?

A

Concentration differences.

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5
Q

True or False: All particles are constantly in motion due to kinetic energy.

A

True.

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6
Q

What types of molecules can easily diffuse across cell membranes?

A

Small, non-polar molecules such as oxygen and carbon dioxide.

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7
Q

What is facilitated diffusion?

A

A passive process that relies on transmembrane channels and carriers to help charged ions and polar molecules move across the membrane.

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8
Q

What are the two types of proteins involved in facilitated diffusion?

A
  • Protein channels
  • Carrier proteins
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9
Q

Fill in the blank: Facilitated diffusion occurs down a _______.

A

[concentration gradient]

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10
Q

What is the primary reason charged ions and polar molecules do not diffuse easily across membranes?

A

The hydrophobic nature of the fatty-acid tails of the phospholipids in the membrane.

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11
Q

True or False: Facilitated diffusion requires an external input of ATP.

A

False.

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