RESPIRATION AND RESPIRATION AND

GAS EXCHANGE

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 CO from the environment evolved: C3, C4, and CAM � 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).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.

Vocabulary words

� aerobic respiration

� air sacs

� alveolus

� anaerobic respiration

� emphysema

� epiglottis

� gas exchange

� gills

� pneumonia� pons� positive pressure breathing� residual volume� respiratory medium� anaerobic respiration

� asthma

� blood pH

� Bohr shift

� breathing

� bronchiole

� bronchus

� C3 pathway

� C4 pathway

� glottis

� glycolysis

� hemocyanin

� hemoglobin

� larynx (voicebox)

� lung Cancer

� lungs

� medulla oblongata

� myoglobin

� nasal cavity

� respiratory medium� respiratory pigments� respiratory surface� rib muscles� spiracle � surface tension� syrinx� thoracic cavity� tidal volume� trachea or windpipe� tracheae� tuberculosis� C4 pathway

� CAM pathway

� cell respiration

� countercurrent exchange

� cutaneous respiration

� diaphragm

� dissociation curve

� nasal cavity

� negative pressure breathing

� nose

� parabronchi

� partial pressure

� pharynx

� photosynthesis

� tuberculosis� ventilation � vital capacity� vocal cords of the larynx

Cellular Respiration- Transformation of chemical energy into ATP

- Overall Reaction: C6H12O6 +6O2 → 6CO2 +6H2O + 36 ATP

1 Glucose molecule 1 Glucose molecule (6C) from digestion

Glycolysis in the cytoplasm �

2 pyruvate molecules (3C)

2 ATPs2 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

NADH and FADH2 are

e- donors that enable the

formation of ATP

Photosynthesis

� Method of converting sun energy into chemical

6 CO2 + 6 H2O + light

energy →C6H12O6 + 6O2

energy into chemical energy usable by cells

� Light reactions

� Dark reactions/Calvin Cycle

Plant adaptations for

acquiring CO2 from the

environment

� C3 (most abundant)

� CO2 converted to a 3C sugar, 3-phosphoglycerate

� RuBisCO (Ribulose-1,5-bisphosphate � 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 cyclepathway/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

Gas exchange supplies oxygen for

cellular respiration and removes CO2

� Gas exchange – uptake of O2 from environment and 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 SA � large

� α 1/d2 � thin

� Moist so gases are dissolved first DIFFUSION

Respiratory surfaces and gas exchange

� Respiratory surface � Simple invertebrates

� Size of organism

� Habitat

� Metabolic demands

� Unicellular organisms

� Entire surface area for

diffusion

� Sponges, cnidarians,

flatworms, roundworms

� diffusion

diffusion

Respiratory surfaces and gas exchange

� More complex animals

� Thin, moist epithelium

Separates medium from � Separates medium from

capillaries

� Entire outer skin � small, long, thin organisms

� Specialized respiratory organs that are extensively

folded and branchedfolded and branched

Gills in aquatic animals

� Outfoldings of the body surface suspended in surface suspended in water

� Sea stars

� Segmented worms or polychaetes

� Molluscs and crustaceans

� Fishes� Fishes

� Young amphibians

� Total surface area is greater than the rest of the body

Water as a respiratory medium

� Surfaces are kept moist

� O2 concentrations in water

are low

Just keep swimming swimmingswimming!

are low

� Ventilation – increasing

flow of respiratory medium

over the surface

� Countercurrent exchange –

process in which two fluids

flow in opposite directions,

swimming!

flow in opposite directions,

maximizing transfer rates

� Why are gills impractical

for land animals?

Air as a respiratory medium

� Air has a higher

concentration of O2

� Tracheal system of insects –network of tubes that bring O2

to every cellconcentration of O2

� O2 and CO2 diffuse

much faster in the air

� less ventilation

� Difficulty of keeping

surface moist

to every cell

Spiraclessurface moist

� Solution: respiratory

infolding inside the

body

Spiracles

Lungs

� Heavily vascularized

invaginations of the body invaginations of the body

surface restricted to one

location

� Found in spiders, terrestrial

snails, vertebrates

� Amphibians supplement

lung breathing with skinlung breathing with skin

� Turtles supplement lung

breathing with moist

surfaces in mouth and anus

Mammalian

respiration

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� “Gulping in” air and pressure

Lung volumes

� Factors

� Sex

� Height

� Tidal volume

� Volume of air inhaled and

exhaled with each breath

� Vital capacity

� Maximum volume inhaled � Height

� Smoking

� Physical activity

� Altitude

� Maximum volume inhaled and exhaled during forced breathing

� Residual volume

� Air left in alveoli after forced

exhalation

Avian breathing

•Air sacs - bellows to keep air flowing through the lungsthrough the lungs•Syrinx – vocal organ of birds

Control

centers in

the brain

regulate regulate

breathing

Gases

diffuse down

pressure

gradients

concentrationand

pressuredrives the

movement of gases into

and out of blood

Respiratory

pigments

� O2 transport

� Low solubility of O2 in � Low solubility of O2 in

H2O

� Respiratory pigments

are proteins with metal

atoms

� Hemoglobin – Fe

� Hemocyanin – Cu� Hemocyanin – Cu

� Allow reversible binding of O2

� Drop in pH results in a lowered affinity of hemoglobin for O2

Respiratory

pigments

� CO2 transport

� 7% in plasma

� 23% bound to

hemoglobin

� 70% as HCO3-� 70% as HCO3

� ***buffer

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 � fetal Hb must be able to bind O2 with greater attraction than maternal Hb

Deep-diving mammals � Seals, whales, dolphins are

capable of long underwater

dives

� Weddell seal � 5% O2 in lungs, 70% in bloodlungs, 70% in blood

� Huge spleen stores huge

volumes of blood

� Large concentrations of

myoglobin in muscles

� Heart rate and O2 � Heart rate and O2

consumption rate decrease

� Blood is redirected from

muscles to brain, spinal

cord, and eyes