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Biology {Gas Exchange and Consequences of Smoking Summer} :tada: - Coggle…
Biology {Gas Exchange and Consequences of Smoking Summer} :tada:
Gas Exchange in Plants
Role of Stomata
Night- guard cells closed, no photosynthesis, (glucose used up/ stored as starch), lose water through osmosis (flaccid) no gas exchange.
Day- guard cells open, photosynthesis, absorb water by osmosis (turgid) more gas exchange.
Net gas exchange is dependent of light intensity
Structure of the Leaf
broad and flat- larger surface area to absorb light, and have more stomata
thin structure- short diffusion distance
stomata- pores open allowing gas exchange to take place
guard cells- open and close for gas exchange
spongy mesophyll- air space increases , larger surface area for diffusion
Structure of the Human Thorax
trachea-
windpipe= draws air from outside to the lungs
bronchi-
2 tubes that the trachea splints into
bronchioles-
branches of bronchi
alveoli
air sacs at the ends of the bronchioles
diaphragm
a sheet of muscle at the bottom of the thorax
ribs-
bones that surround the lungs and give them protection
intercostal muscles-
muscles located between the ribs
pleural membrane-
a moist membrane between thorax and lungs that act as lubrication
Consequences of Smoking
Carbon Monoxide
reduces O2 carried as it binds irreversibly to haemoglobin making carboxy haemoglobin
Tars
carcinogen-
causes lung cancer
chronic bronchitis-
destroys/damages cilia, which carry dust and microbes trapped by mucus away from the lungs, causing the build-up potentially leading to bronchitis as the lining, epithelium of the bronchi becomes irritated. (smoker's cough)
emphysema-
breaks walls of alveoli causing them to merge together, reducing the surface area to volume ratio, less gas exchange, less oxygen is carried to blood.
Nicotine
highly addictive
heart disease-
narrows blood vessels, increasing blood pressure and resting heart rate
Coronary Heart Disease-
coronary arteries narrow that supply heart with blood, meaning less blood will be supplied to them: less oxygen, reduces rate of aerobic respiration which increases risk of heart attack and strokes as coronary arteries are blocked by cholesterol (blood clots)
Investigate effect of light on net gas exchange from a leaf using a hydrogen carbonate indicator:
DORIC:
D:carbon dioxide production O: pondweed R:3 times I:light intensity C: volume and concentration of indicator, temperature, species of pondweed,time
Safety Hazards
keep away from electrical wiring, light source could get hot
Hydrogen Carbonate Indicator
sensitive to changes in pH (CO2 is acidic) very high levels- yellow very low levels- purple average levels- red
Accuracy
it is difficult to tell at which point the indicator changes colour**
Method
1) Fill the boiling tube with a fixed volume of hydrogen carbonate indicator.
2) Place tube rack at a set distance from light source.
3) Add pondweed with the cut stem facing up.
4) Record initial colour of indicator and start stop watch.
5) After 30 mins, record the final colour of the indicator.
6) Repeat with 3 more distances from the light source . The more carbon dioxide released the higher the net gas exchange.
Equipment:
boiling tube, ruler, stop watch light source, tube rack, measuring cylinder, glass rod
Adaptations of Alveoli
large surface area
highly folded and a lot of alveoli to allow for faster diffusion
thin walls-
diffusion distance is short
moist surface-
gases can dissolve for faster diffusion (stops inner walls from sticking together)
good blood supply-
maintains a high concentration gradient so diffusion is faster
permeable-
gases can go through
Gas Exchange in Humans
Gas Exchange-
transfer of oxygen into the blood and carbon dioxide out of the blood across the alveoli walls
Inhalation-
ribs move up and out and diaphragm contracts and flattens so volume increases and pressure decreases so air moves into lungs to expand. (external intercostal muscles contract and internal intercostal muscles relax)
Exhalation-
ribs move down and in and diaphragm relaxes and curves to decrease volume and increase pressure so air moves out of the lungs to deflate. (external intercostal muscles relax and internal intercostal muscles contract)
Investigate breathing in humans (effect of exercise)
1) Count the number of breaths you take each minute while at rest.
2) Do the same after jogging for 5 minutes.
3) Repeat experiment 3 times to take an average for reliability
DORIC
D- rate of breath per minute O-human R- 3 times I- activity level C- time, person used, how much activity done
