Complete breakdown of glucose in the presence of oxygen to release a
large amount of energy in the form of ATP molecules which are used to
drive other chemical reactions in cytoplasm and nucleus Carbon dioxide
and water are waste products
C6H12O6+6O2 --> 6CO2 + 6H2O + Energy
Some energy released as
heat energy to keep warm
38 molecules of ATP built when one molecule of glucose
is completely oxidised to carbon dioxide and water
ATP readily breaks down to adenosine
diphosphate in presence of appropriate
enzyme
Releases energy and phosphate ion
which is used to drive other
chemical reactions
Glycolysis in cytosol
Krebs Cycle
Electron Transport Chains
Mitochondira
Main site of ATP production in
aerobic respiration
Cylinder/Rod Shaped
Double Membrane
Separated by inter membrane space
Outer Membrane is a
smooth continuous
boundary
Inner membrane folded
extensively to form cristae
which project into semi fluid
matrix
Contain circular DNA and
70S ribosomes like bacteria
Once free living bacteria that were ingested by ancestral
eukaryotic cell and stable symbiotic relationship was
established
ANAEROBIC
RESPIRATION
Energy Released from food by breaking it down
chemically but reactions do not use oxygen
although carbon dioxide is often produced
C6H12O6 --> 2C2H5OH + 2CO2 + Energy
Muscles
During exercise, person
starts panting and heart beats
faster
Remove carbon dioxide and take in more oxygen
at a higher rate ; oxygen brought to muscles
faster
Limit on rate of breathing and heartbeat reached so
oxygen may not be delivered to muscle cells fast
enough to meet demands of aerobic respiration
Pyruvic acid buildup exceeds
its oxidation to carbon dioxide
and water using oxygen
Pyruvic acid converted to lactic acid by
enzyme called lactate dehydrogenase
Small amount of
energy released in
the form of ATP
2 molecules of ATP produced for every
glucose molecule used
After exercise, lactic acid from anaerobic respiration
removed
Lactic acid diffuses from muscles to
bloodstream, carrying it to the liver
Lactic acid converted to pyruvic
acid by enzyme lactate
dehydrogenase
Some pyruvic acid oxidized to form
carbon dioxide and water
Release energy in the form of ATP molecules
Energy used to convert
pyruvic acid to glucose
Creates oxygen debt
Oxygen deficit
Amount of oxygen needed but not supplied
from outside of body by breathing
3dm3 of oxygen per min must be supplied to
meet energy demands of exercise aerobically,
but not achieved until 6 min after exercise
began
During lag time, oxygen reserves used
Oxygen in myoglobin
in muscles
Muscle tissues hold
ATP in the form of
creatine phosphate
Oxygen debt
Extra amount of oxygen after exercise,
when rate of oxygen uptake is not resting
requirement of 0.25dm3 per min yet
Used to remove lactic acid from anaerobic respiration
Causes muscle fatigue
Glucose --> Pyruvic Acid/Pyruvate --> Carbon Dioxide + Water
HUMAN GAS EXCHANGE SYSTEM
Passage of Air
Air enters body through tw external nostrils which lead to two
nasal passages
Nostrils bear a fringe of hair to trap dust and
foreign particles
Air warmed and moistened so harmful chemicals are detected by sensory cells in
mucous membrane
Mucus on mucous membrane
also traps dust and foreign
particles
Air passes through internal
nares into pharynx
Air passes into larynx then into trachea through glottis
Epiglottis at the top of trachea stops
food and drink from entering air
passages when we swallow
Divides into two tubes called
the bronchi
Right bronchus divides
into three bronchial
tubes
Left bronchus divides
into two bronchial tubes
Divide into
bronchioles
Alveoli
Thin, moist and well
supplied with blood
capillaries
Blood capillaries transport oxygen
away from lungs and carbon dioxide to
lungs
Maintains large difference in concentration of
gases between blood and alveolus
Maintains steep diffusion gradient
for gases
Gaseous exchange takes
place through walls of
alveoli
Wall is made up of one layer of flattened cells and endothelium
of capillary also one cell thick so that the diffusion distance is
short
Thousands of alveoli in
each lung
Provides large surface area
for gaseous exchange
Inner surface of alveoli coated with
film of moisture
Oxygen dissolves, facilitating diffusion
Some moisture evaporates into alveoli
and saturates air with water vapour
Epithelial cells of alveoli
secrete surfactants
Disrupt cohesive forces between water
molecules
Lowers surface tension of fluid lining alveoli
Increases resistance of lung to stretch
Diagram
Supported by C shaped rings of
cartilage to prevent them from
collapsing when we breathe in
Epithelium
Gland cells
Secrete mucus to trap dust particles
and bacteria
Ciliated cells
Bear cilia to sweep particles up bronchi an
trachea into pharynx
Pleura membrane lies
in the thoracic cavity
Thin layer of lubricating fluid between pleura
allows membranes to glide over each other
easily
Chest wall supported by ribs
External and internal intercostal
muscles found between ribs
Air pressure in lungs reduced below
atmospheric pressure
Air enters lungs, inflating alveoli till pressure in lungs is
equal of atmosphere
Lung capacity and breathing rate
Tidal air is the volume of air inhaled and exhaled
during resting breathing pattern
Complemental air or inspiratory reserve volume is
additional volume of air that can be taken in when
taking a deep breath
Supplemental air or expiratory reserve volume
is the additional volume of air that is forced
out by the most powerful expiratory effort
after normal expiration
1500cn3
Vital capacity is volume of air
expelled by most vigorous
expiratory effort after deepest
inspiration
Residual air is volume of air in
lungs after strongest expiration
Breathing rate about 16 per
min at rest and 20 to 30
breaths per min during
exercise