4.3 - Exchange of Gases in the Lungs

Question 1

Essential Feature of Gas Exchange Surface 1

Answer 1

Large surface area to volume ratio- allows maximum area available for the transfer of gases

Question 2

Essential Feature of Gas Exchange Surface 2

Answer 2

Very thin diffusion pathways - allows the transferred gas to quickly pass between the membranes without having to stay in a cell for too long

Question 3

Essential Feature of Gas Exchange Surface 3

Answer 3

Partially Permeable Membrane - so the materials can actually get through easily

Question 4

Essential Feature of Gas Exchange Surface 4

Answer 4

Constant Movement of Environmental Factor - air - to maintain a fresh supply and therefore a concentration gradient.

Question 5

Essential Feature of Gas Exchange Surface 5

Answer 5

Constant Movement of Internal Factor - blood - to maintain a diffusion gradient

Question 6

Feature of Alveoli and Blood Supply 1

Answer 6

RBCs slowed down - this increases the time given for diffusion to occur

Question 7

Feature of Alveoli and Blood Supply 2

Answer 7

RBC flattened on capillary wall - reduces the distance between alveolar air and RBCs

Question 8

Feature of Alveoli and Blood Supply 3

Answer 8

Capillary wall and Alveolar wall are very thin - shortens the distance between alveolus and RBC

Question 9

Feature of Alveoli and Blood Supply 4

Answer 9

Alveoli and capillaries have an overall high surface area

Question 10

Feature of Alveoli and Blood Supply 5

Answer 10

Constant flow of environmental and internal media to maintain a concentration gradient

Question 11

How do genetic differences arise?

Answer 11

Due to individual genes an organism possesses:

1) mutations - sudden change to a chromosome may be passed onto offspring
2) meiosis - random combination and crossing over of alleles causes varied combinations
3) fusion of gametes - because some alleles are inherited off either parent and there are millions of gamete possibilities, further variety is added

Question 12

How do environmental influences affect variation?

Answer 12

The affect the way the phenotypes of organisms are expressed depending on the place and the way and organism lives

Question 13

Describe the representation of variation due to genetic factors.

Answer 13

Variations due to genetic factors are controlled by a single gene and can therefore only be placed into categories. This means data as a result of singly genetic variation will be discrete and categoric.

Question 14

Describe the representation of variation due to environmental factors.

Answer 14

Polygenes or environmental factors can determine whether a species has a certain characteristic which isn’t categoric, like height.