1. Respiration and Gas exchange

2. Key concepts Types of respiration
Cellular Respiration is the chemical breakdown of food substances to yield ATP.
Different organisms use different kinds of breathing mechanisms in order to transport oxygen throughout their bodies.
Evolutionary adaptations of gas exchange systems and respiration
Different plant adaptations in acquiring CO2 from the environment evolved: C3, C4, and CAM pathways.
Structural adaptations of respiratory apparatus depend on the animal’s habitat. The three most common respiratory organs are gills, tracheae, and lungs.
The respiratory system and circulatory system cooperate directly with each other.
Mammalian respiration
The respiratory system is divided into the upper respiratory tract (nasal passages, mouth, throat, larynx and trachea) and lower respiratory tract (bronchi and the lungs).
Air enters (inhalation) the respiratory system due to a pressure drop inside the lungs (negative pressure).
Air exits (exhalation) the respiratory system due to an increase in pressure inside the lungs.
Breathing is regulated by control centers in the brain (medulla oblongata and pons)
Gases are transported via passive diffusion throughout the body.
Respiratory diseases and their prevention
Respiratory disorders may be congenital or environmental.
Respiratory disorders can be prevented through a combination of proper diet and lifestyle change.

3. Vocabulary words pneumonia pons positive pressure breathing
residual volume
respiratory medium
respiratory pigments
respiratory surface
rib muscles
spiracle
surface tension
syrinx
thoracic cavity
tidal volume
trachea or windpipe
tracheae
tuberculosis
ventilation
vital capacity
vocal cords of the larynx
aerobic respiration
air sacs
alveolus
anaerobic respiration
asthma
blood pH
Bohr shift
breathing
bronchiole
bronchus
C3 pathway
C4 pathway
CAM pathway
cell respiration
countercurrent exchange
cutaneous respiration
diaphragm
dissociation curve
emphysema
epiglottis
gas exchange
gills
glottis
glycolysis
hemocyanin
hemoglobin
larynx (voicebox)
lung Cancer
lungs
medulla oblongata
myoglobin
nasal cavity
negative pressure breathing
nose
parabronchi
partial pressure
pharynx
photosynthesis

4. 2 pyruvate molecules (3C) Electron Transport Chain
Cellular Respiration - Transformation of chemical energy into ATP - Overall Reaction: C6H12O6 +6O2 → 6CO2 +6H2O + 36 ATP
1 Glucose molecule (6C) from digestion
Glycolysis in the cytoplasm 
2 pyruvate molecules (3C)
2 ATPs
Aerobic Respiration in the mitochondria
Krebs Cycle (2 ATPs)
Electron Transport Chain
(32 ATPs)
 CO2+ H2O
Anaerobic Respiration in
the cytosol 
ethanol/lactic acid/CO2

5. NADH and FADH2 are
e- donors that enable the formation of ATP

6. Photosynthesis Light reactions Dark reactions/Calvin Cycle
6 CO2 + 6 H2O + light energy → C6H12O6 + 6O2
Photosynthesis
Method of converting sun energy into chemical energy usable by cells
Light reactions
Dark reactions/Calvin Cycle

7. Plant adaptations for acquiring CO2 from the environment
C3 (most abundant)
CO2 converted to a 3C sugar, 3-phosphoglycerate
RuBisCO (Ribulose-1,5-bisphosphate carboxylase/oxygenase) enzyme catalyzes carbon fixation
prone to photorespiration, lessens efficiency of food production during hot and dry days C4
store CO2 in specialized compartments
convert CO2 into a 4C compound, oxaloacetate
converted into the 3C sugar and CO2 used in the C3 pathway/Calvin cycle
minimizes photorespiration and enhances sugar production
CAM
succulent plants
f ix CO2 at night and store it as 4C organic acids
minimizes water loss and enhances sugar production

9. Gas exchange supplies oxygen for cellular respiration and removes CO2
Gas exchange – uptake of O2 from environment and discharge of CO2
Mitochondria need O2 to produce more ATP, CO2 is the by-product
C6H12O6 + 6O2  6CO2 + 6H2O + 36 ATP
Diffusion rate
α SA  large
α 1/d2  thin
Moist so gases are dissolved first
DIFFUSION

10. Respiratory surfaces and gas exchange
Size of organism
Habitat
Metabolic demands
Unicellular organisms
Entire surface area for diffusion
Simple invertebrates
Sponges, cnidarians, flatworms, roundworms
diffusion

11. Respiratory surfaces and gas exchange
More complex animals
Thin, moist epithelium
Separates medium from capillaries
Entire outer skin
Extensively folded and branched respiratory organs

12. Gills in aquatic animals
Outfoldings of the body surface suspended in water
Sea stars
Segmented worms or polychaetes
Molluscs and crustaceans
Fishes
Young amphibians
Total surface area is greater than the rest of the body

13. Water as a respiratory medium
Just keep swimming swimming swimming!
Adv - Surfaces are kept moist
Disadv - O2 concentrations in water are low
Ventilation – increasing flow of respiratory medium over the surface
Countercurrent exchange – process in which two fluids flow in opposite directions, maximizing transfer rates
Why are gills impractical for land animals?

15. Air as a respiratory medium
Adv - Air has a higher concentration of O2
Adv - O2 and CO2 diffuse much faster in the air  less ventilation
Disadv - Difficulty of keeping surface moist
Solution: respiratory infolding inside the body
Tracheal system of insects – network of tubes that bring O2 to every cell
Spiracles

16. Lungs
Heavily vascularized invaginations of the body surface restricted to one location
Found in spiders, terrestrial snails, vertebrates
Amphibians supplement lung breathing with skin
Turtles supplement lung breathing with moist surfaces in mouth and anus

17. Mammalian respiration

18. Lung ventilation through breathing
Positive pressure breathing in frogs
“Gulping in” air
Negative pressure breathing in reptiles and mammals
Rib muscles and diaphragm change lung volume and pressure

19. Lung volumes Factors Tidal volume Vital capacity Sex Height
Volume of air inhaled and exhaled with each breath
Vital capacity
Maximum volume inhaled and exhaled during forced breathing
Residual volume
Air left in alveoli after forced exhalation
Factors
Sex
Height
Smoking
Physical activity
Altitude

20. Avian breathing
Air sacs - bellows to keep air flowing through the lungs
Syrinx – vocal organ of birds

21. Control centers in the brain regulate breathing

22. Gases diffuse down pressure gradients concentration and pressure drives the movement of gases into and out of blood

23. Respiratory pigments Low solubility of O2 in H2O
Respiratory pigments are proteins with metal atoms
Hemoglobin – Fe
Hemocyanin – Cu
Allow reversible binding of O2
Cooperativity
Drop in pH results in a lowered affinity of hemoglobin for O2

24. Respiratory pigments Low solubility of O2 in H2O
Respiratory pigments are proteins with metal atoms
Hemoglobin – Fe
Hemocyanin – Cu
Allow reversible binding of O2
Cooperativity
Drop in pH results in a lowered affinity of hemoglobin for O2

25. Respiratory pigments CO2 transport 7% in plasma
23% bound to hemoglobin
70% as HCO3- *
*buffers resist pH changes
Respiratory pigments

26. Fetal hemoglobin HbF has greater affinity to O2 than Hb
low O2% by time blood reaches placenta
fetal Hb must be able to bind O2 with greater affinity than maternal Hb

27. Deep-diving mammals
Seals, whales, dolphins are capable of long underwater dives
Weddell seal  5% O2 in lungs, 70% in blood
Huge spleen stores huge volumes of blood
Large concentrations of myoglobin in muscles
Heart rate and O2 consumption rate decrease
Blood is redirected from muscles to brain, spinal cord, and eyes

28. Respiratory disorders
Asthma – chronic inflammatory lung disease
Bronchitis – inflammation of bronchi (chronic/acute)
Emphysema – damage to alveoli
Cystic fibrosis – abnormality in mucus producing glands
Pneumonia – lung inflammation
Tuberculosis – airborne chronic bacterial infection
Lung cancer – normally begins in bronchi, usually carcinomas