Section 4 - Respiration and gas exchange Flashcards
word Equation of anaerobic respiration in humans
Glucose -> lactic acid + energy
word equation for anaerobic respiration in plants and fungi
Glucose -> ethanol + carbon dioxide
Symbol and word equation for aerobic respiration
Glucose + oxygen -> carbon dioxide +water
C6H12O6 + 6O2 -> 6CO2 + 6H2O
Respiration definition
Respiration is turning the chemical energy in food into energy we can use in our body
Name and explain 6 adaptation of a leaf for gas exchange
- Broad - large SA for diffusion
- Air space - this maintains a concentration gradient
- Thin - short diffusion distance
- Stomata - lets gases exchange as they can move in and out of the leaf
- Chloroplasts - increases rate of photosynthesis
- Stomata can close or open by guard cells - increase gas exchange and prevents water loss so it doesn’t dry out
Explain how guard cells open and close
Open: Water enters guard cells by osmosis guard cells become turgid and open
Closes: water leaves guard cells by osmosis guard cells become flaccid closing stomata
How does the stomata manage the water levels in the leaf
When the leaf is full of water, the water moves into the guard cell so it opens and the leaf can lose water
Describe the structure of the thorax
The lungs are surrounded by the ribs and the intercostal muscles. There is a trachea which is connected to the left and right bronchus, then the bronchioles branch out from each bronchus. On the end of the bronchioles are the alveoli. On the outside of the lung there are pleural membranes.
Describe the relationship between photosynthesis and respiration
Plants carry out photosynthesis to produce glucose. To enable this process to occur the leaf cells absorb carbon dioxide and release oxygen.
At the same time the leaf is respiring. This means that they are using oxygen and producing carbon dioxide. When the rate of photosynthesis and respiration are equal the plant is at compensation point.
Describe how the time of day/ weather effects photosynthesis and respiration
If the leaves are in bright sunlight then the rate of photosynthesis will be higher than the rate of respiration.
If there is no light or it is dim the rate of respiration will be higher then the rate of photosynthesis and there will be a net production of CO2
Name the layers of the leaf top down
- Waxy cuticle
- Upper epidermis
- Palisade cells (contain chloroplast) (part of the mesophyll)
- Spongy cells (part of the mesophyll)
- Lower epidermis
- Guard cells
Explain the process of inhalation
- Diaphragm contracts and flattens and external intercostal muscles contract
- Rib cage moves up and out
- Volume of thorax increase
- Pressure decreases
- Air is drawn in
Explain exhalation
- Diaphragm relaxes and external intercostal muscles relax
- Rib cage moves down and in
- Volume of thorax decreases
- Pressure increases
- CO2 is pushed out
Ventilation definition
The movement of air in and out of the lungs
Explain how gas exchange in the alveoli works
Blood which is low on oxygen enters the capillary of the alveoli, CO2 moves into the alveoli from the blood and oxygen moves into the blood from the alveoli
How has the alveoli adapted for gas exchange
- Walls are only one cell thick - provides a short diffusion distance
- Large surface area - Allows more O2 to diffuse in and CO2 to diffuse out
- Good blood supply - maintains the concentration gradient
- Moist- Molecules can on,y cross membranes when dissolved in water
Name for effects of smoking
- Smokers cough
- Lung cancer
- Emphysema
- Carbon monoxide poisoning
Respiration definition
“An exothermic reaction which transfers energy from glucose and is continuously occurring in living cells”
Photosynthesis equation
6H2O + 6CO2 -> C6H12O6 +6O2
Where does aerobic respiration take place
Mitochondria
Where does all respiration take place
cells
What colour does hydrogen carbon indicator turn when a leaf has been in light and why
purple, because the leaf has been photosynthesising so it is using up all the CO2
What colour does hydrogen carbon indicator turn when a leaf has been in darkness and why
Yellow because the leaf has been respiring so it releases a lot of carbon dioxide
How can smoking cause lung cancer
- Chemicals in cigarettes smoke called carcinogens, they are found in the tar which collects in the lungs
- The carcinogens mutate and form a tumour
How can smoking cause emphysema
Smoking damages the walls of alveoli which fuse together to create enlarged and irregular air spaces
This reduces the SA for gas exchange so less oxygen is carried to the blood
How can smoking cause Carbon monoxide poisoning
- The carbon monoxide found in cigarette smoke combines tightly with haemoglobin to form carboxyhemoglobin
- Less oxygen is carried round the body
How can smoking cause smokers cough/chest infections
Tar damages the cilia which usually catches the dust and bacteria and clear mucus
So when cilia is damaged chest infections and smokers cough is more likely
How can smoking cause bronchitis
Tar irritates the brochi and the bronchioles which encourages mucus to be produced but it can’t be cleared as the cilia are damaged
This causes chronic bronchitis
How does light effect the rate of photosynthesis
If the light intensity increases so does the rate of photosynthesis but only up to a certain point
How does carbon dioxide effect the rate of photosynthesis
Increasing the carbo dioxide levels increases the rate of photosynthesis up to a certain point
How does temperature effect the rate of photosynthesis
As temperature increases so does the rate of photosynthesis because the is more kinetic energy for the enzymes but if it gets to hot the enzymes will denature
How are leaves adapted for photosynthesis
1) Leaves are broad, so there’s a large surface area exposed to light.
2) Most of the chloroplasts are found in the palisade layer so they’re near the top of the leaf where they can get the most light.
3) The upper epidermis is transparent so that light can pass through it to the palisade layer.
4) The phloem and xylem deliver water and other nutrients to every part of the leaf and take away the glucose produced by photosynthesis. They also help to support the leaf structure.
5) The waxy cuticle helps to reduce water loss by evaporation.
