IB Biology Topic B3.1.1 Gas Exchange as a Vital Function in All Organisms Revision Notes (SL/HL)

IB Biology Topic B3.1.1 Gas Exchange as a Vital Function in All Organisms Revision Notes (SL/HL) | RevisionDojo

Written by official IB examiners

Gas Exchange Supplies Oxygen and Removes Carbon Dioxide for Every Cell

Definition

Gas exchange

The process by which oxygen enters the body and carbon dioxide is expelled.

Every living organism needs gas exchange to take in oxygen and release carbon dioxide.
Cells need this oxygen for cell respiration, the process that releases the energy they run on.
Respiration also produces carbon dioxide, which is toxic if it builds up, so it must be removed.

Surface Area to Volume Ratio Falls as Organisms Get Bigger

As an organism grows, its volume rises much faster than its surface area.
This gives a large organism less surface area for each unit of volume that needs oxygen.

Analogy

Picture a small cube next to a large cube.
Double the length of each side and the surface area grows four times, but the volume grows eight times.
So a bigger body has proportionally less outer surface to exchange gases through.

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

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Note

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Tip

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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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Gas Exchange Supplies Oxygen and Removes Carbon Dioxide for Every Cell

Definition

Gas exchange

The process by which oxygen enters the body and carbon dioxide is expelled.

Every living organism needs gas exchange to take in oxygen and release carbon dioxide.
Cells need this oxygen for cell respiration, the process that releases the energy they run on.
Respiration also produces carbon dioxide, which is toxic if it builds up, so it must be removed.

Surface Area to Volume Ratio Falls as Organisms Get Bigger

As an organism grows, its volume rises much faster than its surface area.
This gives a large organism less surface area for each unit of volume that needs oxygen.

Analogy

Picture a small cube next to a large cube.
Double the length of each side and the surface area grows four times, but the volume grows eight times.
So a bigger body has proportionally less outer surface to exchange gases through.

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 B3.1.1: Gas Exchange as a Vital Function in All Organisms Notes

Gas Exchange Supplies Oxygen and Removes Carbon Dioxide for Every Cell

Surface Area to Volume Ratio Falls as Organisms Get Bigger

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

Gas Exchange Supplies Oxygen and Removes Carbon Dioxide for Every Cell

Surface Area to Volume Ratio Falls as Organisms Get Bigger

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

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics