IB Biology Topic A2.1.5 Spontaneous Formation of Vesicles by Coalescence of Fatty Acids Into Spherical Bilayers Revision Notes (HL)

IB Biology Topic A2.1.5 Spontaneous Formation of Vesicles by Coalescence of Fatty Acids Into Spherical Bilayers Revision Notes (HL) | RevisionDojo

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Early Membranes: Why Compartmentalization Was Essential

For life to emerge, internal chemistry had to be separated from the external environment.
Membranes provide this separation, allowing cells to maintain stable internal conditions (compartmentalization).
Before true cells existed, simple vesicles (droplets enclosed by lipid bilayers) could have acted as protocells, protecting and concentrating molecules.

Amphipathic Molecules: How Bilayers Form Spontaneously

Definition

Amphiphatic

A molecule with both hydrophilic (water-attracting) and hydrophobic (water-repelling) regions, such as a phospholipid.

On prebiotic Earth, amphipathic molecules like fatty acids were likely present in the "soup" of organic compounds.
Fatty acids have:
1. Hydrophilic head: polar, attracted to water.
2. Hydrophobic tail: non-polar, repelled by water.
When placed in water, these molecules naturally arrange to minimise energy:

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Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

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Early Membranes: Why Compartmentalization Was Essential

For life to emerge, internal chemistry had to be separated from the external environment.
Membranes provide this separation, allowing cells to maintain stable internal conditions (compartmentalization).
Before true cells existed, simple vesicles (droplets enclosed by lipid bilayers) could have acted as protocells, protecting and concentrating molecules.

Amphipathic Molecules: How Bilayers Form Spontaneously

Definition

Amphiphatic

A molecule with both hydrophilic (water-attracting) and hydrophobic (water-repelling) regions, such as a phospholipid.

On prebiotic Earth, amphipathic molecules like fatty acids were likely present in the "soup" of organic compounds.
Fatty acids have:
1. Hydrophilic head: polar, attracted to water.
2. Hydrophobic tail: non-polar, repelled by water.
When placed in water, these molecules naturally arrange to minimise energy:

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

IB Biology Topic A2.1.5: Spontaneous Formation of Vesicles by Coalescence of Fatty Acids Into Spherical Bilayers Notes

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

Early Membranes: Why Compartmentalization Was Essential

Amphipathic Molecules: How Bilayers Form Spontaneously

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

Early Membranes: Why Compartmentalization Was Essential

Amphipathic Molecules: How Bilayers Form Spontaneously

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account