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Title: Cellular respiration notes
Description: Cellular respiration notes including aerobic and anaerobic respiration, human gas exchange and the components of the human respiratory system, inhaled and expired air and the effects of smoking.
Description: Cellular respiration notes including aerobic and anaerobic respiration, human gas exchange and the components of the human respiratory system, inhaled and expired air and the effects of smoking.
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Respiration Notes
Cellular respiration is t
he chemical reactions
that happen in the cells of living
organisms
to sustain
life,
by breaking down food substances to release biochemical energy
...
Respiration is one of the key ways a cell gains useful energy to fuel cellular activity
...
Organisms that use oxygen in respiration are described as aerobic, while those that
do not are anaerobic
...
The energy stored in ATP can then be used to drive processes requiring energy,
including biosynthesis, locomotion or transportation of molecules across cell membranes
...
Although
carbohydratesats
, ,
f
and
proteins
can all be processed and consumed as reactant, this is the preferred method of respiration
...
It can be expressed in C
H O + 6O
>
6 12 6
2
6CO
+ 6H
O + Energy
...
Such organisms need the energy to synthesise new protoplasm, synthesise proteins from amino
acids, conduct active transport, contract muscles, transmit nerve impulses and conduct cell division
...
Anaerobic respiration is energetically less
efficient than aerobic respiration
...
Anaerobic respiration is used mainly by prokaryotes that
live in environments devoid of oxygen
...
E
...
of anaerobes
include yeast, where Ethanol fermentation takes place (C
H O > 2C
H OH +
2CO2
+ Energy)
...
Ethanol is also used as an organic solvent and
disinfectant
...
Ethanol can be mixed with petroleum in
ratios as low as 1:9 to running a car entirely on ethanol
...
Anaerobic respiration also takes place in muscle cells when the limit of oxygen
pumped per minute has been reached
...
Lactic acid is
formed in the process (C
H O > 2C
H O + Energy)
...
Since there is insufficient oxygen to meet the required oxygen
during vigorous muscle contractions, there is an oxygen debt
...
During rest, the breathing rate
continues to be fast for some time so that sufficient oxygen can be taken in to repay the oxygen debt
...
The rest is converted
to glucose
...
Glucose is then
transported back to the muscles
...
Unicellular organisms have a large surface area to volume ratio
and do not need a special gaseous exchange system as gases can be exchanged efficiently
...
These animals use special organs such as lungs and gills so that more efficient gas
exchange can take place
...
The walls of the nostrils bear hairs
...
Air from
the nose enters the pharynx and passes into the larynx and then into the trachea through the
glottis
...
▪
Air is warmed and moistened
...
●
Trachea The trachea (windpipe) is supported by Cshaped rings of cartilage
...
The membrane next to the lumen is the epithelium
...
●
Bronchi and Bronchioles The trachea divides into two tubes called bronchi
...
The bronchi are similar in structure to the trachea
...
Bronchioles are very fine tubes and
they end in alveoli
...
Numerous alveoli are found in
the lungs, providing a large surface area to volume ratio for gaseous exchange
...
This provides a short diffusion distance for gases, ensuring a
faster rate of diffusion
...
The walls are rich with blood capillaries
...
Blood entering the lungs has a lower concentration of
oxygen and a higher concentration of carbon dioxide than the atmospheric air entering the alveoli
...
Oxygen
diffuses from the alveolar air into the blood capillaries and carbon dioxide diffuses in the opposite
direction
...
Oxygen Absorption
1
...
2
...
3
...
4
...
Carbon Dioxide Removal
1
...
2
...
3
...
4
...
Hence, most of the carbon dioxide is carried as hydrogencarbonate ions in the blood
plasma
...
In the lungs, hydrogencarbonate ions diffuse back into the red blood cells where they are
converted into carbonic acid and then into water and carbon dioxide
...
The carbon dioxide is then diffused out of the blood capillaries and into the alveoli, where it is
breathed out
...
Humans possess special breathing mechanisms that increase the rate of
gas exchange
...
The workings of the
intercostal muscles and the diaphragm change the volume of the thoracic cavity
...
The ribs are attached dorsally to (at the back) the
vertebral column so that in can move up and down
...
Humans have 12 pairs of ribs but only the first 10 pairs are attached
to the sternum while the other pairs are free ribs
...
They are antagonistic muscles and when the external intercostal muscles contract, the
internal intercostal muscles relax, and vice versa
...
The diaphragm is made of muscle and elastic tissue
...
The diaphragm muscle contracts and the diaphragm flattens
...
The external intercostal muscles contract and the internal intercostal muscles relax
...
The ribs move upwards and outwards and the sternum moves up and forward
...
The volume of the thoracic cavity increases
...
The lungs expand and air pressure inside decreases as the volume increases
...
Atmospheric pressure is now higher than the pressure within the lungs, forcing air into the lungs
...
The diaphragm muscle relaxes and the diaphragm arches upwards
...
The external intercostal muscles relax and the internal intercostal muscles contract
...
The ribs move downwards and inwards and the sternum moves down to its original position
...
The volume of the thoracic cavity decreases
...
The lungs compress and air pressure inside increases as the volume decreases
...
Atmospheric pressure is now lower than the pressure within the lungs, forcing air out of the
lungs
...
4%
Carbon Dioxide
0
...
When there is too little carbon dioxide in the lungs, breathing movements do not occur
...
The higher the concentration of carbon dioxide, the higher the
breathing rate would be
...
Harmful Chemicals in Tobacco Smoke
●
Nicotine An addictive drug that causes the release of adrenaline
...
It also increases the risk of blood clots in the arteries, which
leads to increased risk of coronary heart disease
...
It reduces the ability of blood to carry oxygen and it narrows the lumen of
arteries, leading to an increase in blood pressure
...
It increases
lung cancer risk and dust particles trapped in the mucus lining the air passages cannot be
removed, increasing risks of chronic bronchitis and emphysema
...
Diseases caused by tobacco smoke
●
Chronic Bronchitis Prolonged exposure to irritant particles that are found in tobacco smoke may
cause chronic bronchitis
...
Excessive
mucus is secreted by the epithelium
...
Mucus and dust
particles that are trapped cannot be removed
...
Persistent coughing is needed to clear the airways and this increases the risk of getting
lung infections
...
The
partition walls between the alveoli break down due to persistent and violent coughing, resulting
in a decreased surface area to volume ratio for gas exchange
...
Breathing becomes difficult and wheezing and severe breathlessness
result
...
Title: Cellular respiration notes
Description: Cellular respiration notes including aerobic and anaerobic respiration, human gas exchange and the components of the human respiratory system, inhaled and expired air and the effects of smoking.
Description: Cellular respiration notes including aerobic and anaerobic respiration, human gas exchange and the components of the human respiratory system, inhaled and expired air and the effects of smoking.