Respiration and Gas Exchange Flashcards
(20 cards)
What is respiration
The process from which energy is released
Chemical and word equation for aerobic respiration
Glucose + oxygen–> carbon dioxide + water + energy (ATP)
C6H12O6 + 6O2–> 6CO2 + 6H2O + energy
Word equation for anaerobic reparation in animals
Glucose–> lactic acid + energy + energy
Word equation for anaerobic reparation in plants
Glucose–> ethanol + carbon dioxide + energy
Experiment to see that heat and carbon dioxide are wast products of respiration
Bubble gas released through limewater
= goes milky if CO2
Record temperature before experiment and after= there will be a rise.
Role of diffusion in gas exchange
Oxygen enters the blood and carbon dioxide leaves the blood.
Gases diffuse across the walls of the alveoli.
- Oxygen goes into the blood as there is a lower concentration in the blood
- Carbon dioxide diffuses into the lungs as there is a lower conc of it In the lungs
Gas exchange in plants
Photosynthesis= co2 taken in and o2 given out.
Respiration= o2 taken in, co2 given out.
What does the overall amount of CO2 and O2 depend on?
Light intensity.
How is the structure of a leaf adapted to gas exchange?
Spongy mesophyll= internal air spaces increase surface area for the leaf to absorb more CO2. Loosely packed and are covered by a thin film of water.
Guard cells around the stomata= guard cells open and close stoma depending on how much water there is (turgid or flaccid)
How does stoma control gas exchange in the leaf
In the light, water is taken in by osmosis for photosynthesis making the plant turgid. This opens stoma and allows gas exchange to occur.
At night= water is not taken in as photosynthesis cannot occur, so plant becomes flaccid. This closes the stoma.
How can you carry out an experiment to see the effect of light on gas exchange?
1) place a pond weed in water with hydrogen carbonate indicator (og orange)
2) have a lamp at set distances (close= high light intensity and far away= low light intensity)
3) repeat at different distances
Indicator is yellow when there is a lot of CO2= high light intensity,
Purple when there is little CO2= low light intensity.
What happens when we breathe in?
Intercostal muscles contract
Diaphragm contracts and moves down.
Volume of thorax increases and rib age moves up and out
pressure decreases=Air sucked in.
What happens when we breathe out
Intercostal muscles relax
Diaphragm relaxes and moves in
Ribcage moves in and down and thorax volume decreases
Pressure increases, air is pushed out.
Adaptations of alveoli
Folded= large surface area for gas exchange to occur Thickness= alveoli walls are one cell thin= short diffusion distance. Capillaries= rich blood supply maintains conc. gradient. Ventilated= each alveolus is well ventilated so co2 is removed and O2 levels are replenished= high conc. gradient.
Effects of smoking on the lungs
Cigarettes contain harmful chemicals
E.,g nicotine= addictive drug
Carbon monoxide= poisonous.
How does smoking affect air passages ?
Cigarette smoke damages cilia hairs so they cannot sweep out the mucus with trapped pathogens. To get rid of it, smokers cough a lot and this damages the walls of the alveoli= bronchitis
Effect of smoking on alveoli
Smoke damages the walls of the alveoli causing them to break down and join together= large gaps= small surface area (emphysema)
This reduces efficiency of gas exchange so oxygen levels in blood are low= exercise is difficult.
Effects of smoking in terms of carbon monoxide?
Incomplete combustion from cigarette smoke= CO
Combines with haemoglobin in red blood cells= reduces the blood’s oxygen carry capacity= strain on circulatory system and an increased risk of coronary heart disease and strokes.
How does smoking cause lung cancer
Tobacco smoke contains many carcinogens, including tar which increases the risk of mouth, Throat and lung cancer.
Effect of exercise in breathing?
1) Count breath in 10 seconds from a stationary person and multiply by 6 to get results for one minute.
2) repeat again, but after doing exercise.
Plot results on graph= overall trend is that breathing rate increase as intensity of exercise increases too.
