Respiration

Question 1

How did oxygen build up in the atmosphere

Answer 1

Cyanobacteria in oceans started producing oxygen via photosynthesis

Question 2

what was Earth’s first mass extinction

Answer 2

oxygen build up killed anaerobic bacteria

Question 3

What does oxygen serve as

Answer 3

an electron acceptor in the oxidation of carbon-based fuels

Question 4

what are the four reasons oxygen is consumed

Answer 4

1. Stable and abundant in the atmosphere
2. Reduction of O2 = large free energy release/e- transfer
3. aerobic metabolism = 4x more energy/mol glucose oxidized than anaerobic
4. can diffuse across membrane and bind to heme moieties in proteins = O2 delivery to organs and electron transfer functions

Question 5

How does gas exchange take place

Answer 5

via diffusion, gas diffuses down pressure gradients created by differences in partial pressures, requires a large surface area

Question 6

Respiration in worms

Answer 6

they do not have a RS, open CS = capillaries near surface, diffusion over whole body occurs

Question 7

What are the two sources animals can extract O2 from?

Answer 7

air and water

Question 8

What is the differences of O2 in air vs. water

Answer 8

less O2 available in water (water = denser and more viscous = harder to move), obtaining O2 from water requires more effort

Question 9

What two factors affect O2 solubility?

Answer 9

temperature and solute concentration (proportional)

Question 10

How do aquatic animals extract O2 from water

Answer 10

Gills

Question 11

What are gills

Answer 11

Internal or external outfoldings of the body that create a large surface area for gas exchange

Question 12

How do fish gills work?

Answer 12

Fish gills use a countercurrent exchange system —> blood flows in the opposite direction to water passing over the gills
Blood PO2 is always < Water PO2 (blood = less saturated) so oxygen diffuses down the pressure gradient

Question 13

how efficient are fish gills

Answer 13

more than 80-90% of the O2 in the water is removed

Question 14

What RS do insects use

Answer 14

tracheal system = network of tubes throughout the body that supplies O2 to every cell
CS and RS = separate

Question 15

what are some components of the tracheal system and what is their function?

Answer 15

Spiracles = openings connected to trachea, gated to minimize water loss
Sacs = air storage

Question 16

what must large insects do to meet O2 demands?

Answer 16

they must actively ventilate their TS

Question 17

How do amphibians breathe

Answer 17

Through positive pressure breathing which ventilated their lungs by forcing air down the trachea (air forced in/out)

Question 18

How do birds breath?

Answer 18

Have 8/9 sacs that keep air flowing through the lungs, with air passing through in one direction. Air is passed through the entire system in two cycles of inhalation and exhalation. Highly efficient

Question 19

Pathway of air through a bird

Answer 19

1st inhalation —> posterior air sacs —> 1st exhalation —> lungs —> 2nd inhalation —> anterior air sacs —> 2nd exhalation

Question 20

what is inhalation/exhalation in birds

Answer 20

inhalation = air sacs fill
exhalation = air sacs empty and lungs fill

Question 21

What is the pathway of air through the RS in mammals?

Answer 21

Nostrils —> pharynx —> larynx —> trachea —> bronchi —> bronchioles

Question 22

what do nostrils do

Answer 22

filter, warm, humidify and sample air for odors

Question 23

what does the pharynx do

Answer 23

directs air to lungs and food to stomach

Question 24

how is food prevented from entering the trachea

Answer 24

swallowing moves larynx upward and the epiglottis covers the glottis in the pharynx

Question 25

why does air not go to the stomach?

Answer 25

there is no negative pressure

Question 26

How is the respiratory system kept clean?

Answer 26

mucus escalator = cilia and mucus line the epithelium of the air ducts and move particles up to the pharynx, allows particles to be swallowed into the esophagus

Question 27

What is the impact of the CFTR gene

Answer 27

Cl-/HCO3- imbalances

Question 28

What is the role of Cl- in mucous production?

Answer 28

Cl- allows for the flow of water, low Cl- levels = no hydrated mucous = thick and sticky

Question 29

What are alveoli function and structure

Answer 29

site of gas exchange, air sacs at tips of bronchioles with a moist film of epithelium

Question 30

why are alveoli susceptible to contamination

Answer 30

lack cilia

Question 31

what do alveoli secrete and why?

Answer 31

surfacants (detergent) which break surface tension

Question 32

How do mammals ventilate their breathing

Answer 32

negative pressure breathing = pulls air into lungs

Question 33

what is tidal volume

Answer 33

the volume of air inhaled with each breath

Question 34

what is the vital capacity

Answer 34

maximum tidal volume

Question 35

What occurs during inhalation

Answer 35

diaphragm contracts (moves down) increasing lung volume, rib cage expands

Question 36

what occurs during exhalation

Answer 36

diaphragm relaxes (moves up) and ribs cage gets smaller

Question 37

what remains after exhalation and why

Answer 37

residual volume of air to prevent collapse of lungs

Question 38

What are the partial pressure s of O2 and Co2 in the blood arriving in the lungs relative to alveoli

Answer 38

low O2, high CO2

Question 39

where does each gas diffuse in the alveoli

Answer 39

O2 diffuses into blood, Co2 diffuses into air

Question 40

what occurs in tissue capillaries for diffusion

Answer 40

pressure gradients favour diffusion of O2 into the IF and CO2 into the blood

Question 41

Where does O2 diffuse to

Answer 41

1. alveolar spaces ---> lung capillaries 2. Systemic capillaries ---> tissues

Question 42

Where does Co2 diffuse to

Answer 42

1. tissues ---> systemic capillaries 2. lung capillaries ---> alveolar spaces

Question 43

What is the pathway of oxygenated air following inhalation

Answer 43

Alveolar spaces, AV/lung capillaries , pulmonary veins, heart, systemic arteries, systemic capillaries, tissue

Question 44

What is the pathway of Co2 in deoxygenated blood following diffusion out of the body tissue

Answer 44

tissue, systemic capillaries, systemic veins, heart, pulmonary arteries, lung capillaries, AV spaces, exhalation

Question 45

What are respiratory pigments

Answer 45

proteins that transport oxygen and increase the amount of oxygen the blood can carry

Question 46

what respiratory pigments is used by arthropods and molluscs and what is its binding component

Answer 46

hemocyanin, copper

Question 47

what respiratory pigment do most vertebrates and some invertebrates use

Answer 47

hemoglobin,

Question 48

what are hemoglobins structure

Answer 48

made of dimers (alpha and beta subunits ---> 2 each) which contain 4 iron-containing heme groups

Question 49

how many oxygen molecules can each hemoglobin molecule carry

Answer 49

up to four

Question 50

What is binding affinity defined by

Answer 50

kd (dissociation constant)

Question 51

How does affinity affect Hb ability to bind

Answer 51

high affinity = low saturation of O2 needed to bind low affinity = high saturation needed to bing

Question 52

What does oxygen bind to in hb

Answer 52

Iron (protoporphyrin)

Question 53

What are the qualities of the tense state

Answer 53

low affinity, deoxygenated, compact structure (hard for O2 to bind), low cooperativity

Question 54

what are the characteristics of the relaxed state of Hb

Answer 54

high affinity, oxygenated, open structure (easy for O2 to bind), high cooperativity

Question 55

what does the dissociation curve for hemoglobin and oxygen essentially mean

Answer 55

in areas of high oxygen availability, oxygen is not needed to be unloaded so saturation is high (lungs), in tissues at rest, oxygen availability is lower due to respiration of the tissues, meaning some oxygen needs to be unloaded from the hemoglobin leading to lower saturation, in tissues during exercise lots of oxygen is being consumed so there is little oxygen availability meaning lots of oxygen needs to be unloaded leading to low saturation

Question 56

What factors cause a shift right and why

Answer 56

increased PCO2, Lower pH, increased temperature, and increased BPG Lowers the oxygen affinity of Hb ---> oxygen is unloaded easier assisting O2 delivery

Question 57

What is BPG and how does it affect Hb?

Answer 57

Product of glycolysis, fits into the whole in the Hb of the T state preventing O2 from binding favours T state, not R state

Question 58

What are the characteristics of myoglobin and what is its function

Answer 58

emergency store of oxygen (for the heart), monomeric = 1 subunit = no cooperativity = no R/T state found in muscles

Question 59

Where is Co2 transported

Answer 59

7% = blood plasma 23% = binds to amino group of Hb 70% = transported as bicarbonate

Question 60

What is carbon monoxide poisoning caused by

Answer 60

Co binds to heme group in Hb more strongly than O2, creating HbCO

Question 61

How is breathing controlled

Answer 61

sensors in aorta and carotid arteries monitor Co2 and O2 concentrations in blood and signal breathing control centers

Question 62

What are the breathing control centers

Answer 62

main = medulla oblongata, additional = pons

Question 63

What are some adaptations in marine animals (6)

Answer 63

large blood to body volume ratio stockpile O2 Store O2 in myoglobin of muscles change buoyancy for passive gliding anaerobic respiration decrease blood supply to muscles