Bioenergetics Flashcards
Is photosynthesis endo or exothermic?
endothermic - it takes in energy from the light
What is the word equation for photosynthesis?
carbon dioxide + water —–> glucose + oxygen
light
What four factors affect the rate of photosynthesis?
- Amount of chlorophyll
- Light intensity
- Level of CO2
- Temperature
What happens when temperature increases?
Enzymes work faster until around 45° where the enzymes denature
What are 5 ways glucose is used/stored in a plant?
- For respiration
- Making cellulose
- Making amino acids
- Stored as oils / fats
- Stored as starch
When is starch converted into glucose in a plant?
When there is no photosynthesis occuring
e.g. at night or in winter
How do you use pondweed to measure the effect of light intensity on photosynthesis?
- Cut off a piece of pondweed and put it into a test tube with water and put the cut end on top. Place a funnel above the pondweed with a measuring cylinder on top.
- Place the test tube 10cm away from an LED light source
- Let the test tube sit there for 5 mins to adjust to the climate
- Measure the volume of oxygen released from the pondweed in 1 min and repeat 3 times.
- Repeat from 20cm, 30cm, 40cm.
What is the inverse square law?
1/distance^2
If you halve the distance the light intensity will be 4x greater, if you third the distance the light intensity will be 9x greater e.t.c.
Why is it inaccurate to count the bubbles produced from pondweed yourself?
- bubbles can move too fast to count
- not all bubbles are the same size
How do greenhouses increase the yield of crops?
- They have light: windows and artificial lights
- High heat: greenhouse traps sun’s heat, heater (+ ventilation when too hot)
- High CO2 levels: using paraffin heater
- Being indoors keeps pests and diseases away
What is the word equation for aerobic resipiration?
glucose + oxygen –> carbon dioxide + water
–> (+ lots of energy)
What is the word equation for anaerobic respiration?
glucose —> lactic acid
–> (+ little energy)
What is the word equation for fermentation?
glucose –> ethanol + carbon dioxide
What is anaerobic respiration?
The incomplete breakdown of glucose, making lactic acid
What is fermentation?
Anaerobic respiration in yeast cells
What can fermentation be used to make?
bread + beer / alcohol
Why do you increase respiration during exercise?
More muscles contract and therefore require more energy so respiration increases to meet the demand
How does your body respond to exercise?
- Breathing rate increases
- Breathing volume increases
- Heart rate increases
What effect does lactic acid have on muscle?
When it builds up in muscle, it causes pain and muscle fatigue so muscles stop contracting efficiently
What is oxygen debt?
The amount of extra oxygen needed after exercise to react with lactic acid to remove it from the cells
this is why you continue heavy breathing after exercise
Where is lactic acid converted into glucose?
In the liver
It is transported by blood
Describe how vigorous exercise leads to oxygen debt
During exercise, it’s harder for the body to supply oxygen to the muscles so anaerobic respiration takes place creating lactic acid
Define metabolism
the sum of all chemical reactions in a cell or the body
What 3 large molecules can glucose form when joined together?
small molecule –> large molecule
- Starch
- Cellulose
- Glycogen
