IB Biology Topic A2.2.3 Developments in Microscopy Revision Notes (SL/HL)

IB Biology Topic A2.2.3 Developments in Microscopy Revision Notes (SL/HL) | RevisionDojo

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Electron Microscopy: Higher Resolution Through Electrons

Advantages of Electron Microscopy

Reveals ultrastructure: it can show organelles, membranes, and even large molecules like viruses.
High magnification: it reaches up to 500,000 times or more.
Fine detail: it shows the internal organisation of cells and the arrangement of membrane structures.

Two Main Types Of Electron Microscopy

Transmission Electron Microscopy (TEM)
1. Electrons pass through thin sections of the specimen.
2. It reveals internal structures in a 2D cross-section.
3. It is best for viewing organelles, membranes, and internal cellular organisation.
Scanning Electron Microscopy (SEM)
1. Electrons scatter off the surface of the specimen.
2. It produces 3D surface images.
3. It is best for viewing external cell structure and surface topology.

Freeze-Fracture Electron Microscopy: Viewing Membrane Interiors

Definition

Freeze-fracture EM

A specialized technique for studying the internal structure of cell membranes.

Cells are rapidly frozen, usually in liquid nitrogen.
The frozen sample is fractured with a knife.
The fracture often splits membranes along their middle, between the two phospholipid layers.
The fractured surface is coated with platinum or carbon to create a replica.

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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.
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Electron Microscopy: Higher Resolution Through Electrons

Advantages of Electron Microscopy

Reveals ultrastructure: it can show organelles, membranes, and even large molecules like viruses.
High magnification: it reaches up to 500,000 times or more.
Fine detail: it shows the internal organisation of cells and the arrangement of membrane structures.

Two Main Types Of Electron Microscopy

Transmission Electron Microscopy (TEM)
1. Electrons pass through thin sections of the specimen.
2. It reveals internal structures in a 2D cross-section.
3. It is best for viewing organelles, membranes, and internal cellular organisation.
Scanning Electron Microscopy (SEM)
1. Electrons scatter off the surface of the specimen.
2. It produces 3D surface images.
3. It is best for viewing external cell structure and surface topology.

Freeze-Fracture Electron Microscopy: Viewing Membrane Interiors

Definition

Freeze-fracture EM

A specialized technique for studying the internal structure of cell membranes.

Cells are rapidly frozen, usually in liquid nitrogen.
The frozen sample is fractured with a knife.
The fracture often splits membranes along their middle, between the two phospholipid layers.
The fractured surface is coated with platinum or carbon to create a replica.

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 A2.2.3: Developments in Microscopy Notes

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

Electron Microscopy: Higher Resolution Through Electrons

Advantages of Electron Microscopy

Two Main Types Of Electron Microscopy

Freeze-Fracture Electron Microscopy: Viewing Membrane Interiors

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Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

Electron Microscopy: Higher Resolution Through Electrons

Advantages of Electron Microscopy

Two Main Types Of Electron Microscopy

Freeze-Fracture Electron Microscopy: Viewing Membrane Interiors

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