2.2 Adaptations for Gas Exchange in animals

Question 1

🧬 Exchange of Materials in Organisms
Need for Exchange:

Answer 1

Cells require oxygen, glucose, and water for metabolism.

They produce waste products (CO₂, nitrogenous waste, water) that must be removed.

Question 2

🧬 Exchange of Materials in Organisms
Cell Membrane Transport Mechanisms:

Answer 2

Simple diffusion: Gases (O₂, CO₂) & non-polar molecules pass through the phospholipid bilayer.

Facilitated diffusion: Polar/charged substances use specific channel or carrier proteins.

Osmosis: Movement of water through aquaporins or membrane from high to low water potential.

Active transport: Moves substances against the concentration gradient using ATP and carrier proteins.

Endocytosis/exocytosis: Bulk transport of large particles or fluids.

Surface Area to Volume Ratio (SA:V):

Question 3

🧬 Exchange of Materials in Organisms
Surface Area to Volume Ratio (SA:V):

Answer 3

Exchange happens at surface area, but metabolic needs depend on volume.

As organisms get larger:

Volume increases faster than surface area.

SA:V ratio decreases.

Diffusion becomes less efficient, so specialised exchange surfaces are needed.

Question 4

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Question 5

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Question 6

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Question 7

🌬️ Factors Affecting Diffusion Rate

SA

Answer 7

↑ SA = ↑ diffusion rate

More membrane means more space for molecules to pass through.

Adaptation: Folding of surfaces (e.g. microvilli in intestines) increases SA.

Question 8

🌬️ Factors Affecting Diffusion Rate

diffusion distance

Answer 8

↓ distance = ↑ diffusion rate

Shorter paths reduce time for substances to travel.

Adaptation: Thin exchange surfaces (e.g. one-cell thick alveoli or capillaries).

Question 9

🌬️ Factors Affecting Diffusion Rate

gradient and how this is maintained

Answer 9

↑ gradient = ↑ diffusion rate

Steeper gradient means faster net movement of molecules.

Maintained by:

Ventilation (e.g. lungs bring in O₂, remove CO₂)

Circulation (blood carries O₂/CO₂ to and from tissues)

Cell respiration (uses O₂, produces CO₂)

Water movement (e.g. fish moving keeps fresh water flowing over gills)

Turbulence (mixes water, increases O₂ availability)

Question 10

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Question 11

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Question 12

🦠 Unicellular Organisms (e.g. Amoeba) and Gas Exchange

Answer 12

Question 13

label amoeba

Answer 13

Question 14

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Question 15

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Question 16

🪱 Flatworms (Multicellular Organisms) and Gas Exchange

Answer 16

Question 17

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Question 18

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Question 19

🪱 Earthworms and Gas Exchange

Answer 19

Question 20

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Question 21

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Question 22

Amphibia (Gas Exchange and Circulation):

Answer 22

Question 23

specialised gas exchange surfaces

Answer 23

in large multicellular animals
help overcome problem of low SA to Vol ration and long diffusion distances
circulatory system - helps maintain conc gradient (brings oxygenated blood to tissue and removes carbon dioxide)Haemoglobin has a high affinity for oxygen and absorbs and transports oxygen.

Generally, these gas exchange surfaces must have:
a large surface area
a short diffusion path
ventilation mechanisms for maintaining a concentration gradient
permeability to gases
moist surfaces so oxygen can dissolve in the water and diffuse across them.

Question 24

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Question 25

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Question 26

Gas Exchange in Fish Problem: Adaptation: Gills

Answer 26

Question 27

Gas Exchange in Fish Structure of Gills:

Answer 27

Question 28

Gas Exchange in Fish Ventilation in Fish: Operculum

Answer 28

Question 29

Gas Exchange in Fish Blood Supply:

Answer 29

Question 30

Gas Exchange in Fish Adaptations in Active Fish:

Answer 30

Question 31

Gas Exchange in Fish

Answer 31

Question 32

Gas Exchange in Fish

Answer 32

Question 33

Gas Exchange in Fish

Answer 33

Question 34

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Question 35

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Question 36

Ventilation in Fish Purpose of Ventilation:

Answer 36

Question 37

Ventilation in Fish Bony Fish: Positive Pressure Ventilation

Answer 37

Question 38

Ventilation in Fish Ram Ventilation (in some sharks):

Answer 38

Question 39

Ventilation in Fish Bony Fish vs RAM

Answer 39

Question 40

Ventilation in Fish

Answer 40

Question 41

Ventilation in Fish

Answer 41

Question 42

Countercurrent and concurrent blood flow in fish gills 🦈 Cartilaginous Fish (e.g., sharks)

Answer 42

Question 43

Countercurrent and concurrent blood flow in fish gills 🐟 Bony Fish

Answer 43

Question 44

Countercurrent and concurrent blood flow in fish gills 💡 Why Countercurrent is Better:

Answer 44

Question 45

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Question 46

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Question 47

The gas exchange system in mammals consists of the following: Larynx

Answer 47

this is the ‘voice box’ and contains the vocal cords enabling sounds to be produced.

Question 48

The gas exchange system in mammals consists of the following: Trachea

Answer 48

a pipe that connects the lungs to the pharynx; it has C-shaped rings of cartilage that prevent the trachea collapsing when pressures in the lungs are negative.

Question 49

The gas exchange system in mammals consists of the following: Bronchi

Answer 49

two bronchi branch off the lower end of the trachea delivering air to each lung. Rings of cartilage prevent the bronchi collapsing.

Question 50

The gas exchange system in mammals consists of the following: Bronchioles

Answer 50

smaller branches from the bronchi delivering air to all parts of the lung; muscle permits constriction to control the flow of air in and out of the alveoli.

Question 51

The gas exchange system in mammals consists of the following: Alveoli

Answer 51

the site of gas exchange, these consist of sacs of air surrounded by flattened (squamous) epithelia. The large number of alveoli give a massive surface area to the lungs and the flattened epithelial cells give a short diffusion path. The alveoli are surrounded by capillaries which maintain a concentration gradient. The blood contains haemoglobin which transports oxygen away from the gas exchange surface. Carbon dioxide diffuses from the plasma into the alveoli to be excreted.

Question 52

The gas exchange system in mammals consists of the following: Pleural membranes

Answer 52

these surround the lungs and secrete pleural fluid. The pleural membranes are involved in negative pressure breathing.

Question 53

The gas exchange system in mammals consists of the following: Ribs

Answer 53

protect the heart and lungs.

Question 54

The gas exchange system in mammals consists of the following: Intercostal muscles

Answer 54

these sit between the ribs, contraction of these muscles raises the rib cage in ventilation.

Question 55

The gas exchange system in mammals consists of the following: Diaphragm

Answer 55

a muscle that separates the thorax and abdomen, contraction of this muscle pulls the diaphragm down in ventilation.

Question 56

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Question 57

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Question 58

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Question 59

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Question 60

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Question 61

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Question 62

Structure and Function of the Trachea 1. Ciliated Epithelium

Answer 62

Question 63

Structure and Function of the Trachea 2. Cartilage Rings

Answer 63

Question 64

Structure and Function of the Trachea 3. Smooth Muscle

Answer 64

Question 65

# \

Answer 65

Question 66

Answer 66

A - rings of cartilage B - containing Goblet cells C - oesophagus D- ?

Question 67

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Question 68

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Question 69

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Question 70

Adaptations of the Alveoli for Gas Exchange

Answer 70

Question 71

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Question 72

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Question 73

Inspiration (breathing in):

Answer 73

Question 74

In expiration (breathing out):

Answer 74

The muscles relax and the opposite to the image below happens:

Question 75

Ventilation in mammals

Answer 75

* negative pressure ventilation mechanism * bringing oxygenated air to lungs, removing carbon dioxide rich air from lungs, to maintain conc gradient between blood and alveoli

Question 76

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Question 77

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Question 78

Gas Exchange in Insects Water Conservation Adaptations

Answer 78

Insects have a high surface area to volume ratio, making them prone to water loss. To reduce desiccation, their body is covered in a chitin exoskeleton with a waterproof waxy layer. As a result, gas exchange cannot occur across the body surface.

Question 79

Gas Exchange in Insects Gas Exchange Structures

Answer 79

Spiracles: Small openings on the exoskeleton that allow gases to enter and exit. Tracheae: Tubes lined with chitin that branch from the spiracles. Chitin prevents the tubes from collapsing. Tracheoles: Fine tubes that extend close to cells – this is where gas exchange takes place.

Question 80

Gas Exchange in Insects Mechanism of Gas Exchange

Answer 80

Question 81

Answer 81

tracheole

Question 82

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Question 83

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Question 84

Structure and Control of Spiracles in Insects Location & Arrangement

Answer 84

Question 85

Structure and Control of Spiracles in Insects Function & Adaptation

Answer 85

Question 86

Structure and Control of Spiracles in Insects Control Mechanism

Answer 86

Question 87

Structure and Control of Spiracles in Insects Spiracular Fluttering

Answer 87

Question 88

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Question 89

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Question 90

Ventilation in Insects Inhalation (Air In)

Answer 90

Question 91

Ventilation in Insects Exhalation (Air Out)

Answer 91

Question 92

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Question 93

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Question 94

Insect Flight Muscle and Gas Exchange 🪶 High Metabolic Demand

Answer 94

Question 95

Insect Flight Muscle and Gas Exchange 🧬 Tracheole Penetration

Answer 95

Question 96

Insect Flight Muscle and Gas Exchange ⚡ During Flight

Answer 96