Respiration + Gas Exchange Flashcards
Aerobic Respiration
https://www.bbc.co.uk/bitesize/guides/zm6rd2p/revision/1
The release of a relatively large amount of energy in
cells by the breakdown of glucose in the presence of
oxygen
Occurs in all cells (mitochondria)
Key: Different to breathing/ventilation
Aerobic Respiration equation
Glucose + Oxygen -> Carbon Dioxide + Water
C6H12O6 + 6O2 → 6CO2 + 6H2O
Anaerobic Respiration
It is the release of a relatively small amount of energy in cells by the breakdown of food substances in the absence of oxygen.
Glucose is not completely broken down, so much less energy is released than during aerobic respiration.
Build-up of lactic acid in muscles during vigorous exercise -> oxidised later to carbon dioxide and water
This causes an oxygen debt - excess post-exercise oxygen consumption (EPOC) - ‘repaid’ after the exercise stops -> we keep breathing deeply for a few minutes after finished exercising.
Anaerobic Respiration equation - in animals
Glucose -> Lactic Acid
Anaerobic Respiration equation - in plants/yeasts
Glucose -> Ethanol + Carbon Dioxide
- Used during brewing, bread making
Inhalation
Intercostal muscles: Contract
Ribs: move up and out
Diaphragm: Pulled flat
Exhalation
Intercostal Muscles; relax
Ribs: Down and In
Diaphragm: Dome - shaped (goes up)
ATP
ATP provides energy for cells
Experiment: Production of Carbon Dioxide by small organisms
- Soak dried beans in water for a few days (so they start to germinate
- Put hydrogen carbonate indicator, gauze and beans in test tube with rubber bung.
- Because beans are respiring, hydrogen carbonate indicator will go from orange (atmospheric levels) -> yellow (presence of CO2)
Control: Glass beads
Experiment: Production of heat by small organisms
- Soak dried beans in water for a few days (so they start to germinate
- Boil different batch of peas to denature enzymes
- Wash peas in bleach to remove microbes, then distilled water
- Put both peas in vacuum flask with thermometer and seal with cotton wool (allows CO2 to escape)
- Measure initial temp and final temp
- Increase in temp in vacuum flask with soaked peas as they are respiring
Adaptations of Alveolus for gas exchange
- High Surface Area
- Thin walls (1 cell thick) = short diffusion distance
- Good blood supply = maintains steep conc. gradient
- Permeable Walls = even gas diffusion
What happens in an alveolus
Gas Exchange (between air in lungs and blood in capillaries)
O2 diffuses out
CO2 diffuses in
Biological Consequences of Smoking
Chemicals in Cigarettes
- Tar
- Carbon Monoxide
- Tobacco
Chemicals in Cigarettes - Tar
Paralyses/destroys cilia so mucus cannot be sept out of lungs = smokers cough
Chemicals in Cigarettes - Carbon Monoxide
Binds irreversibly to haemoglobin so reduces capacity of blood to carry oxygen
Chemicals in Cigarettes - Nicotine
Narrows blood vessels = increases blood pressure + heart rate
Coronary Heart Disease
when your coronary arteries become narrowed by a build-up of fatty material within their walls.
So less blood to heart, so less oxygen to heart
So muscle cells respire less
Build up of lactic acid from anaerobic respiration
Heart attack
Lung diseases
Emphysema
Bronchitis
Emphysema
Reduces S.A of alveoli -> less oxygen into the blood causing shortness of breath
Bronchitis
Inflammation of bronchi -> shortness of breath
How do plants exchange gases
Diffusion
Gas exchange in plants
- When plants photosynthesise, they use up CO2, and produce O2 as a waste product
- When plants respire, they use up O2, and produce CO2 as a waste product
How does O2 leave the plant as a waste product of photosynthesis?
Diffuses out of stomata
