Respiration Flashcards

1
Q

What is the word AND chemical equation for aerobic respiration?

A

glucose + oxygen > carbon dioxide + water + large amount of energy release
C6H12O6 + 6 O2 > 6 CO2 + 6 H2O + energy

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2
Q

What is the overall equation for anaerobic respiration in yeast?

A

glucose > ethanol + carbon dioxide + small amount of energy released

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3
Q

What is the overall equation for anaerobic respiration in human muscles?

A

glucose > lactic acid + small amount of energy released

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4
Q

Describe the process of energy conversion in muscle cells during exercise.

A

During vigorous muscular contractions (exercise), your muscle cells first respire aerobically. You may start panting in order to remove carbon dioxide and take in oxygen at a faster rate. Your heart will also begin to beat faster so that oxygen can be transported to your muscles at a faster rate. However, there is a limit to the increase in the rate of breathing and heartbeat.

When muscular contractions are so vigorous that maximum aerobic respiration is unable to release energy fast enough to meet the demand, your muscle cells carry out anaerobic respiration to release extra energy to keep your muscles contracting. Lactic acid is formed in the process.

Since there is insufficient oxygen to meet the demands of vigorous muscular contractions, the muscles are said to incur an oxygen debt.

During the period of rest, the breathing rate continues to be fast for some time to provide sufficient oxygen to the muscle cells, to repay the oxygen debt. Lactic acid is gradually removed from the muscles and transported to the liver.

In the liver, some of the lactic acid is oxidised to release energy, which is used to convert the remaining lactic acid into glucose. When all the lactic acid has been converted, the oxygen debt is repaid. Glucose is then transported back to the muscles and the body is ready for another race.

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5
Q

How are the lungs adapted for efficient gas exchange?

A

There are numerous alveoli in the lungs, which provides a very large surface area for gaseous exchange. (note: NOT an adaptation of alveoli)
The alveolar wall is only one cell thick, providing a short diffusion distance for gases and hence a faster rate of diffusion.
A thin film of moisture covers the surface of the alveolus, allowing oxygen to dissolve in it.
As the walls of the alveoli are richly supplied with blood capillaries, the continuous flow of blood maintains the concentration gradient of gases.
The movement of air in and out of the alveoli due to breathing maintains a steep concentration gradient of gases for a faster rate of diffusion.

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6
Q

State the functions of the gland cells and ciliated cells.

A

Gland cells secrete mucus to trap dust particles and bacteria.

Ciliated cells have hair-like structures called cilia that sweep the dust-trapped mucus up the trachea.

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7
Q

Describe the removal of carbon dioxide from the lungs, including the role of the carbonic anhydrase enzyme.

A

Tissue cells produce a large amount of carbon dioxide as a result of aerobic respiration.
As blood passes through these tissues via blood capillaries, carbon dioxide diffuses into the blood and enters the RBCs.
The carbon dioxide then reacts with the water in the RBCs to form carbonic acid. This reaction is catalysed by the enzyme carbonic anhydrase, which is present in RBCs.
The carbonic acid is then converted into hydrogencarbonate ions which diffuse out of the RBCs. Hence, most of the carbon dioxide is carried as hydrogencarbonate ions in the blood plasma. A small amount is also carried and dissolved in the RBCs.
In the lungs, hydrogencarbonate ions diffuse back into the RBCs 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 from the lungs when you breathe out.

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8
Q

Describe the role of the diaphragm, ribs and intercostal muscles in breathing

A

Inspiration / Inhalation: [ RICE ]
The diaphragm muscle contracts and the diaphragm flattens.
The external intercostal muscles contract, while the internal intercostal muscle relax.
The ribs move upwards and outwards. The sternum also moves up and forward.
The volume of the thoracic cavity increases.
The lungs expand and the air pressure inside them decreases as the volume increases.
Atmospheric pressure is now higher than the pressure within the lungs, forcing atmospheric air into the lungs.

Expiration / Exhalation: [ ERIC ]
The diaphragm muscle relaxes and the diaphragm arches upwards.
The internal intercostal muscles contract, while the external intercostal muscles relax.
The ribs move downwards and inwards. The sternum also moves down to its original position.
The volume of the thoracic cavity decreases.
The lungs are compressed and the air pressure inside them increases as the volume decreases.
Pressure within the lungs is now higher than atmospheric pressure, forcing air out of the lungs to the exterior environment.

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9
Q

What is the stimulus for breathing?

A

High concentration of carbon dioxide in the blood or alveolar air.

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10
Q

Describe the effect of nicotine in tobacco smoke on health.

A

Properties:
- Addictive drug that causes the release of the hormone adrenaline
- Makes blood clot easily.

Effects on the body:
- Increases heartbeat rate and blood pressure
- Increases the risk of blood clots in the arteries, which leads to increased risk of coronary heart disease

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11
Q

Describe the effect of carbon monoxide in tobacco smoke on health.

A

Properties:
- Combines with haemoglobin in RBCs to form carboxyhaemoglobin
- Increases the rate of fatty deposits on the inner arterial wall, which leads to increased risk of coronary heart disease

Effects on the body:
- Reduces the ability of blood to carry oxygen
- Narrows the lumen of arteries and leads to increase in blood pressure

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12
Q

Describe the effect of tar in tobacco smoke on health.

A

Properties:
- Causes uncontrolled cell division
- Paralyses cilia lining the air passages

Effects on the body:
- Increases the 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

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13
Q

What are the effects of chronic bronchitis and what is it caused by?

A

titties
- Caused by prolonged exposure to irritant particles that are found in tobacco smoke
- The epithelium lining of the air passages, like the bronchi, becomes inflamed
- Excessive mucus is secreted by the epithelium
- The cilia on the epithelium are paralysed, so mucus and dust particles cannot be removed
- The air passages become blocked, making breathing difficult
- Persistent coughing to clear air passages, in order to breathe, increases the risk of getting lung infections

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14
Q

What are the effects of emphysema and what is it caused by?

A
  • Persistent and violent coughing due to bronchitis may lead to emphysema
  • The partition walls between the alveoli break down due to persistent and violent coughing
  • This results in a decreased surface area for gaseous exchange
  • The lungs lose their elasticity and become inflated with air
  • Breathing becomes difficult, and wheezing and severe breathlessness result.
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