Biochemistry

Enzymes

Word and chemical equations

Energy transfer

Nutrition

Digestion

Transport and circulation

Gas exchange

Transpiration and translocation

Tropisms

MYP Biology Gas Exchange Notes

What Is Gas Exchange?

Definition

Gas exchange

The transfer of oxygen into the body and carbon dioxide out across a specialized surface.

Gas exchange is the movement of oxygen into an organism and carbon dioxide out of it.

All living cells need oxygen for aerobic respiration and must remove carbon dioxide to maintain healthy internal conditions.

Gas exchange happens wherever gases cross a specialized surface, such as alveoli, gills, tracheoles, or stomata.

Hint

You don't need to memorize these but it's good to know:
- Alveoli -> air sacs in the lungs of mammals (and some reptiles)
- Gills -> how fish breathe
- Tracheoles -> respiratory tubes
- Stomata -> gas exchange on plants

What Makes an Effective Gas Exchange Surface?

Effective gas exchange surfaces share structural features that maximise the rate at which gases can move across them.

Across organisms, these adaptations tend to follow the same principles:

Large surface area: Allows more gas to diffuse across at the same time.
Very thin barriers: Reduces the distance gases must travel.
Moist surfaces: Allows gases to dissolve before crossing membranes.
Steep concentration gradients: Maintained by blood flow or ventilation to keep gases moving in the right direction.

Hint

If a structure is thin, moist, and highly folded, it is probably adapted for rapid gas exchange.
Again, form follows function!

How Does Gas Exchange Occur in Human Lungs?

Human lungs exchange gases in tiny air sacs called alveoli that sit next to an extensive capillary network.

Oxygen moves from the air inside each alveolus into the blood, while carbon dioxide moves from the blood into the alveolus to be exhaled.

Key structural features:

Millions of alveoli provide a large surface area
Alveolar and capillary walls are each one cell thick

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Definition

Paywall

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

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MYP Biology Gas Exchange Notes

What Is Gas Exchange?

What Makes an Effective Gas Exchange Surface?

How Does Gas Exchange Occur in Human Lungs?

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What Is Gas Exchange?

What Makes an Effective Gas Exchange Surface?

How Does Gas Exchange Occur in Human Lungs?

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Cells7 subtopics

Organisms7 subtopics

Processes10 subtopics

Metabolism4 subtopics

Evolution7 subtopics

Interactions with environment6 subtopics

Interactions between organisms5 subtopics

Human interactions with environments3 subtopics

Biotechnology3 subtopics

MYP Biology Gas Exchange Notes

Cells7 subtopics

Organisms7 subtopics

Processes10 subtopics

Metabolism4 subtopics

Evolution7 subtopics

Interactions with environment6 subtopics

Interactions between organisms5 subtopics

Human interactions with environments3 subtopics

Biotechnology3 subtopics

What Is Gas Exchange?

What Makes an Effective Gas Exchange Surface?

How Does Gas Exchange Occur in Human Lungs?

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

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What Is Gas Exchange?

What Makes an Effective Gas Exchange Surface?

How Does Gas Exchange Occur in Human Lungs?

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

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