c10 respiration Flashcards
what is respiration?
the oxidation of food molecules to release energy
why do living things respire?
living organisms respire as they need energy to move, grow, excrete and reproduce. energy is obtained from food consumes and to use the energy available in food, living things need to break down the food molecules through a process called oxidation. the oxidation of food molecules to release energy is called respiration.
two types of respiration?
aerobic and anaerobic repiration
what is aerobic respiration?
aerobic respiration is the process of breaking down food molecules (glucose) in the presence of oxygen with the release of a large amount of energy. carbon dioxide and water are released as waste products.
word and chemical eqn of aerobic respiration in humans
chemical equation: C6H12O6 + 6O2 = 6CO2 + 6H2O + energy
word equation: glucose + oxygen -> carbon dioxide + water + large amount of energy
site of aerobic respiration
mitochondria of all cells, is catalysed by enzymes (meaning reaction is affected by temperature)
processes that consume energy (7 examples)
- synthesis of new protoplasm for growth and repair
- synthesis of proteins from amino acids
- active transport in the absorption of food substances by the small intestine
- muscular contractions such as heartbeats and respiratory movements
- transmission of nerve impulses
- cell division (growth)
- released as heat. this heat energy is circulated around your body by the blood to keep you warm (to maintain body temperature)
what is anaerobic respiration?
anaerobic respiration is the process of breaking down food molecules in the absence of oxygen. it releases significantly less energy in comparison to aerobic respiration
site of anaerobic respiration and when it happens
happens in the muscle cells when aerobic respiration is unable to meet the demand for energy in the cells
word and chemical eqn for anaerobic respiration in humans
chemical equation: C6H12O6 -> 2C3H6O3 + small amount of energy
word equation: glucose -> lactic acid + small amount of energy
another term for anaerobic respiration in humans?
lactic acid fermentation
another term for anaerobic respiration in yeast
alcoholic fermentation
chemical and word eqn for alcoholic fermentation
chemical equation: C6H12O6 -> 2 C2H5OH + 2 CO2
word equation: glucose -> ethanol + carbon dioxide + small amount of energy
atp
molecule of energy
what is alcoholic fermentation?
many microorganisms can respire aerobically and anaerobically. am example is yeast. the little amount of energy released from anaerobic respiration is enough for the yeast to survive, but they cannot be very active under such conditions. yeast releases ethanol and carbon dioxide as waste products during anaerobic respiration., also called alcoholic fermentation.
what happens during exercise and why? (16 part, the whole process, from change to norm)
- during vigorous muscular contractions, your muscle cells first respire aerobically
- you may begin panting in order to remove carbon dioxide and take in oxygen at a faster rate
- your heart will begin to beat faster so that oxygen and glucose can be transported to your muscles at a faster rate
- however, there’s a limit to the increase in the rate of breathing and heartbeat
- when aerobic respiration is unable to release energy fast enough to meet the demand, muscle cells carry out anaerobic respiration to release extra energy
- lactic acid is formed in the process
- energy is released from anaerobic respiration and aerobic respiration helps the muscle keep contracting
- since there’s insufficient oxygen to meet the demands of vigorous muscular contractions, ,the muscles are said to incur an oxygen debt
- lactic acid concentrations build up slowly (accumulate) in the muscles, and may eventually become high enough to cause muscular fatigue and muscular pains
- the body then needs to rest and recover
- during this period of rest the breathing rate continues to be fast for some time
- this is to provide sufficient oxygen to muscle cells to repay the oxygen debt
- lactic acid is also removed from the muscles and transported to the liver
- in the liver, ,some of the lactic acid is oxidised to release energy. this energy is then used to convert the remaining lactic acid into glucose.
- when all the lactic acid is used up the oxygen debt is repaid
- glucose is then transported back to the muscle. ready for exercise again
difference between respiration and photosynthesis (5)
- energy released vs energy stored in carbohydrate molecules
- oxygen is used whereas carbon dioxide and water are given off vs carbon dioxide and water are used whereas oxygen is given off
- catabolic process, resulting in the breakdown of carbohydrate molecules vs anabolic process, resulting in the building up of carbohydrate molecules
- occurs at all times in all cells, independent of chlorophyll and sunlight vs occurs only in cells containing chlorophyll and in the presence of sunlight
- results in a loss of dry mass vs results in a gain of dry mass
l: respiration, r: photosynthesis
(glucose used = lost in dry mass)
flow of air in human respiratory system (7 parts)
nasal cavity -> pharynx -> larynx -> trachea -> bronchi -> bronchioles -> alveoli
define breathing
breathing is the transport of oxygen from the outside air to the cells, and carbon dioxide from the cells to the outside air. this is not the same as cellular respiration, which is the process by which an organism breaks down food molecules to release energy for life processes.
constituents of the human respiratory system (7 parts)
nasal passages pharynx larynx trachea bronchi, branches into bronchioles lungs related muscles: ribs, diaphragm
nasal cavity functions (3)
- the fringe of hair and mucous layer on the walls of the nasal cavity trap dust and foreign particles.
- as air passes through the air passages, it is warmed and moistened
- harmful chemicals may be detected by the sensory cells in the mucous membrane
trachea function
epithelium of trachea and bronchi:
- gland cells secrete mucus that trap dust particles and bacteria in the air that is channelled to the lungs
- ciliated cells have hair-like structures known as cilia that sweep the trapped particles and bacteria in mucus up the bronchi and trachea, into the pharynx
bronchi what is + function
what is nasal cavity/nasal passage
passaged leading from the nostrils lined with a moist mucous membrane
what is trachea
a tube supported by c-shaped cartilage connecting the larynx and the lungs. the c-shaped cartilage prevents the trachea from collapsing as the air pressure in the lungs changes. it branches into two bronchi, one to each lung.
what is pharynx
common passage for the opening of the oesophagus and the trachea
bronchi and bronchioles what is + function
- the trachea divides into two tubes called bronchi (singular: bronchus)
- each bronchus carries air into the lung. the bronchi are similar in structure to the trachea
- each bronchus branches repeatedly, giving rise to numerous bronchioles
- each bronchiole ends in a cluster of air sacs or alveoli (singular: alveolus)
bronchioles what is
alveoli (air sacs) what is?
site of gaseous exchange
about alveoli
- concentration gradient of oxygen should be maintained such that concentration of oxygen in alveolar air is greater than that in the blood, so that oxygen can enter the blood by diffusion
- concentration gradient of carbon dioxide should be maintained such that the concentration of carbon dioxide in alveolar air is lower that that in the blood, so that carbon dioxide can leave the body by diffusion
adaptations of alveolus (4)
- the numerous alveoli in the lungs increase the surface area to volume ration for gaseous exchange
- the alveolar wall and capillary wall are only one cell thick, this reduces diffusion distance for gases, ensuring faster rate of diffusion
- the inner alveolar surface is coated with a thin film of moisture. this allows oxygen to dissolve in it
- concentration gradients of gases between blood and alveolar air are maintained by:
(a) continuous flow of blood in blood capillaries surrounding alveoli
(b) movement of air in and out of alveoli due to breathing
how is oxygen transported in the body?
- oxygen molecules bind to haemoglobin (Hb) reversibly in red blood cells to form oxyhaemoglobin
- 1 haemoglobin molecule binds with 4 oxygen molecules.
haemoglobin and oxygen bind in high o2 conditions to form oxyhaemoglobin. - reaction reverses in low o2 concentrations.
how is carbon dioxide transported?
- carbon dioxide molecules from respiring cells enter the red blood cells in the bloodstream.
the carbon dioxide then reacts with water in the red blood cells to form carbonic acid.
this reaction is catalysed by the enzyme carbonic anhydrase which is present in rbcs
word eqn: carbon dioxide + water ⇌ carbonic acid
chemical: co2+h2o ⇌ h2co3 - the carbonic acid is then converted into hydrogencarbonate ions which diffuse out of the red blood cells. hence, most of the carbon dioxide is carried as hydrogencarbonate ions in the blood plasma.
carbonic acid ⇌ hydrogen ion + hydrogen carbonate ion
h2co3 ⇌ h+ +hco3- - in the lungs, hydrogen carbonate 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 then diffuses out of the blood capillaries and into the alveoli, where it is expelled when you breathe out
thoracic cavity and intercostal muscles
the ribs support the chest wall
two sets of muscles can be found between the ribs: external intercostal muscles and internal intercostal muscles
they are antagonistic muscles (work opposite of one another)
intercostal muscles move the rib cage up and down during breathing
thorax is separated from abdomen by diaphragm (muscle and elastic tissues)
mechanism of inspiration (inhalation)
when you inspire (breathe in), the following events take place:
your diaphragm muscle contracts and diaphragm flattens
your external intercostal muscles contract while your internal intercostal muscles relax. your ribs move upwards and outwards. your sternum(middle of ribcage) also moves up and forward
volume of thoracic cavity increases
your lungs expand and air pressure inside them decreases as the volume increases.
atmospheric pressure is now higher than the pressure within your lungs
this forces atmospheric air into your lungs.
mechanism of expiration (exhalation)
when you expire (breathe out), the following events take place:
your diaphragm muscles relaxes and diaphragm arches upwards
your internal intercostal muscles contract while your external intercostal muscles relax.
your ribs move downwards and inwards. your sternum also moves down to its original position.
the volume of your thoracic cavity decreases.
your lungs are compressed and air pressure inside them increases as the volume decreases.
pressure within the lungs is now higher than atmospheric pressure.
the air is forced out of your lungs to the exterior environment.
differences in inspired and expired air
decrease: oxygen, dust particles (trapped) increase: carbon dioxide, temperature, water vapor saturation. same: nitrogen
stimulus for breathing
the stimulus for breathing is a high concentration of carbon dioxide in the blood or alveolar air, and not a lack of oxygen. when there is too little carbon dioxide in the lungs, breathing movements do not occur.
an experiment conducted on measuring the number of breaths per minute taken by the human subjects breathing in:
atmospheric air composed of 21% oxygen and 0.03% carbon dioxide
100% pure oxygen
air composed of 90% oxygen and 10% carbon dioxide
harmful chemicals in tobacco smoke (4)
nicotine
carbon monoxide
tar
irritants (e.g. hydrogen cyanide, acrolein, formaldehyde)
harmful properties of nicotine
- addictive drug that causes the release of the hormone
- adrenaline makes blood clot easily
- increases heartbeat rate and blood pressure
- increases risk of blood clots in arteries, which leads to increased - risk of coronary heart disease
harmful properties of carbon monoxide
- combines with haemoglobin to form carboxyhaemoglobin (has higher affinity with haemoglobin that o2, irreversible reaction
- increases the rate of fatty deposits on the inner atrial wall (causing coronary heart disease)
causes:
- reduces ability of blood to carry oxygen
- narrows the lumen of arteries and leads to increase in blood pressure and an increase in blood pressure and an increased risk of coronary heart
harmful properties of tar
carcinogenic (cancer causing)
- causes uncontrolled cell division
- paralyses cilia lining in the air passages
causes:
- increases risk of cancer in lungs
- dust particles trapped in the mucus lining the air passages cannot be removed, increasing the risks of chronic bronchitis and emphysema
harmful properties of irritants (hydrogen cyanide, acrolein, formaldehyde)
- paralyses cilia lining the air passages
- dust particles trapped in the mucus lining the air passages cannot be removed, increasing the risks of chronic bronchitis and emphysema
what is chronic bronchitis?
- the epithelium lining in the airways is inflammed
- there is excessive mucus secretion
- the cilia lining the airways are paralysed and unable to remove mucus and dust
- symptoms include:
- breathing difficulties due to blocked airways
- persistent cough (body’s response to clear blocked airways and breathe). increasing risks to lung infections.
what is emphysema
the disease causes
- the partition walls to break down due to persistent and violent coughs from bronchitis
- this reduces the surface area to volume ratio for gaseous exchange
- the lung lose their elasticity and become inflated with air
- symptoms include:
- breathing difficulties
- wheezing and severe breathlessness
what is lung cancer
- cancer is the uncontrolled division of cells producing outgrowths or lumps of tissues.
- smoking also increases the risk of cancers of the mouth, throat, pancreas, kidneys and urinary bladder
