100% satisfaction guarantee Immediately available after payment Both online and in PDF No strings attached
logo-home
Summary Notes on Gas Exchange - AQA A Level Biology £10.49
Add to cart

Summary

Summary Notes on Gas Exchange - AQA A Level Biology

 0 purchase

Summary notes on Gas Exchange - AQA A Level Biology A* and A quality Tailored to mark schemes as with all of my notes AQA mark scheme specific Used past papers mark schemes to make all of my notes

Last document update: 1 year ago

Preview 2 out of 14  pages

  • September 7, 2023
  • January 27, 2024
  • 14
  • 2023/2024
  • Summary
All documents for this subject (187)
avatar-seller
studytogether
For all parts of the specification you MUST learning the phrasing of the Learning Outcomes


3.3.2 Gas exchange
Summary notes
Learning Outcome
a Adaptations of gas exchange surfaces, shown by:
- Gas exchange across the body surface of a single celled organism.
b - In the tracheal system of an insect (tracheae, tracheoles and spiracles)
c - Across the gills of fish (gill lamellae and filaments including the counter-current principle)
d - By the leaves of dicotyledonous plants (mesophyll and stomata).
e Structural and functional compromises between the opposing needs for efficient gas exchange
and the limitations of water loss shown by terrestrial insects and xerophytic plants
f The gross structure of the human gas exchange system limited to the alveoli, bronchioles, bronchi,
trachea and lungs.
g The essential features of the alveolar epithelium as a surface over which gas exchange takes place
h Ventilation and the exchange of gases in the lungs. The mechanism of breathing to include the
role of the diaphragm and the antagonistic interaction between the external and internal
intercostal muscles in bringing about pressure changes in the thoracic cavity.

Students could be given the values of pulmonary ventilation rate (PVR) and one other measure,
requiring them to change the subject of the equation.
PVR = tidal volume x breathing rate

i Be able to interpret information relating to the effects of lung disease on gas exchange and / or
ventilation
j Be able to interpret data relating to the effects of pollution and smoking on the incidence of lung
disease.
k Be able to analyse and interpret data associated with specific risk factors and the incidence of lung
disease.
L Be able to evaluate the way in which experimental data led to statutory restrictions on the
sources of risk factors.
m Be able to recognise correlations and causal relationships
n Be able to use Spearman’s rank correlation.

3.3.2 a - Adaptations of gas exchange surfaces, shown by gas exchange across the body surface
of a single celled organism.

Single-celled organisms have no specialised gas exchange surfaces or transport systems. Instead,
they rely upon diffusion alone to exchange gases. Typically these organisms have flat cells or
foldings in their cell surface membrane. This increases their surface area (and therefore SA:VOL)
and ensures a short diffusion distance. Small multi-cellular organisms without specialised gas
exchange surfaces also typically have flat body shapes for the same reason as above.




Single-celled amoeba Multicellular flatworm

, 3.3.2 b - Adaptations of gas exchange surfaces in the tracheal system of an insect (tracheae,
tracheoles and spiracles)

3.3.2 e - Structural and functional compromises between the opposing needs for efficient gas
exchange and the limitations of water loss shown by terrestrial insects

As multicellular organisms with a small SA:VOL (compared to single celled organisms) , adult
insects cannot rely upon diffusion across their surface to exchange gases – the rate of diffusion
would be too slow. Instead, insects have a gas exchange system called the tracheal system. This is
not too dissimilar in structure to the human gas exchange system. Both systems work by a basic
principle that air enters an opening into the animal’s body and travels down a series of smaller
and smaller tubes deeper into the animal before gas exchange occrs.

Human
component of gas Insect
“equivalent”
exchange system

Mouth Spiracle

Trachea Tracheae

Bronchioles Tracheoles

Cartilage rings to Chitin rings to
support trachea support tracheae


The major differences are that a human only has one opening with the atmosphere (one mouth)
whereas insects typically have many openings (spiracles) along their abdomen. In addition,
Humans exchange gases into the blood from alveoli. The blood then carries oxygen and carbon
dioxide to/from muscles around the body. On the other hand, insect have no transport system so
exchanges gases directly from their tracheal system into muscles (not into blood)


Spiracle
Muscle (opening to
atmosphere)




Tracheae

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

Guaranteed quality through customer reviews

Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.

Quick and easy check-out

Quick and easy check-out

You can quickly pay through credit card for the summaries. There is no membership needed.

Focus on what matters

Focus on what matters

Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!

Frequently asked questions

What do I get when I buy this document?

You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.

Satisfaction guarantee: how does it work?

Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.

Who am I buying these notes from?

Stuvia is a marketplace, so you are not buying this document from us, but from seller studytogether. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy these notes for £10.49. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

69252 documents were sold in the last 30 days

Founded in 2010, the go-to place to buy revision notes and other study material for 15 years now

Start selling
£10.49
  • (0)
Add to cart
Added