IB Biology Topic A2.2.2 Microscopy Skills Revision Notes (SL/HL)

IB Biology Topic A2.2.2 Microscopy Skills Revision Notes (SL/HL) | RevisionDojo

Written by official IB examiners

Temporary Mounts Let You View Living Cells Quickly

The first step in observing cells is to prepare a slide.
A temporary mount lets you examine fresh or living specimens without complex preparation.

Tip

These mounts are quick to assemble.
They are ideal for observing dynamic processes such as cell division or the movement of organelles.

How to Prepare a Temporary Mount

Obtain the specimen: select a thin layer of cells or tissue, such as the lower epidermis of a leaf or cells scraped from the inside of your cheek.
Place on the slide: lay the specimen flat on a clean microscope slide.
Add a drop of water or stain: use water to keep the cells hydrated, or apply a stain like methylene blue or iodine to highlight structures such as the nucleus or starch granules.
Lower the cover slip: using forceps, gently lower a cover slip at an angle to avoid trapping air bubbles.
Remove excess liquid: blot away any excess water or stain from the edges of the cover slip with a paper towel.

Common Mistake

Trapping air bubbles under the cover slip is a common error.
Lower the cover slip slowly and at an angle to avoid it.

Choosing the Right Stain

Tip

Use methylene blue to stain animal cells such as cheek cells.
Use iodine to stain plant cells such as banana cells.
These stains highlight key structures like the nucleus or starch granules.

Always Focus From Low Power to Protect the Slide

Focusing correctly is essential for a clear image.

Always start with the lowest magnification, for example 40 times.
1. Position the slide: place it on the stage, secure it with stage clips, and centre the area of interest over the light source.
2. Coarse focus: use the coarse focusing knob to bring the specimen into view, moving the stage away from the objective lens to prevent damage.

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Temporary Mounts Let You View Living Cells Quickly

The first step in observing cells is to prepare a slide.
A temporary mount lets you examine fresh or living specimens without complex preparation.

Tip

These mounts are quick to assemble.
They are ideal for observing dynamic processes such as cell division or the movement of organelles.

How to Prepare a Temporary Mount

Obtain the specimen: select a thin layer of cells or tissue, such as the lower epidermis of a leaf or cells scraped from the inside of your cheek.
Place on the slide: lay the specimen flat on a clean microscope slide.
Add a drop of water or stain: use water to keep the cells hydrated, or apply a stain like methylene blue or iodine to highlight structures such as the nucleus or starch granules.
Lower the cover slip: using forceps, gently lower a cover slip at an angle to avoid trapping air bubbles.
Remove excess liquid: blot away any excess water or stain from the edges of the cover slip with a paper towel.

Common Mistake

Trapping air bubbles under the cover slip is a common error.
Lower the cover slip slowly and at an angle to avoid it.

Choosing the Right Stain

Tip

Use methylene blue to stain animal cells such as cheek cells.
Use iodine to stain plant cells such as banana cells.
These stains highlight key structures like the nucleus or starch granules.

Always Focus From Low Power to Protect the Slide

Focusing correctly is essential for a clear image.

Always start with the lowest magnification, for example 40 times.
1. Position the slide: place it on the stage, secure it with stage clips, and centre the area of interest over the light source.
2. Coarse focus: use the coarse focusing knob to bring the specimen into view, moving the stage away from the objective lens to prevent damage.

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 A2.2.2: Microscopy Skills Notes

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

Temporary Mounts Let You View Living Cells Quickly

How to Prepare a Temporary Mount

Choosing the Right Stain

Always Focus From Low Power to Protect the Slide

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

Temporary Mounts Let You View Living Cells Quickly

How to Prepare a Temporary Mount

Choosing the Right Stain

Always Focus From Low Power to Protect the Slide

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