TOPIC 4 - BIOENERGETICS Flashcards
(30 cards)
What is the word equation for photosynthesis?
carbon diuoxide + water –> oxygen + glucose
What is the balanced symbol equation for photosynthesis?
6CO2 + 6H2O –> 6O2 + C6H12O6
What is photosynthesis?
An endothermic reaction in which energy is transferred from the environment to the chloroplasts by light
Explain the effects of temperature on the rate of photosynthesis
As temp increases, enzymes work faster until optimum temp, beyond this they denature and rate decreases.
Explain the effects of light intensity on the rate of photosynthesis
Light provides the energy required for photosynthesis increasing it to a point. Beyond this point, factors like CO2 limit the rate.
Explain the effects of carbon dioxide concentration on the rate of photosynthesis
As CO2 increases, so does photosynthesis until a point. Beyond that point, factors like temperature and light intensity limit the rate.
Explain the effects of the amount of chlorophyll on the rate of photosynthesis
As chlorophyll increases, so does photosynthesis until a point. Beyond that point, factors like CO2 concentration, light intensity and temp limit the rate.
What is the inverse square law and light intensity in terms of photosynthesis?
As the distance from a light source increases, the light intensity decreases proportionally to the square of the distance. This means if you double the distance from the light source, the light intensity is reduced to 1/4 of its orginal value.
How does the inverse square law and light intensity affect the rate of photosynthesis?
Light intensity is a limiting factor - as light intensity decreases due to increased distance, the rate of photosynthesis decreases.
Why are limiting factors important in the economics of enhancing the conditions in greenhouses?
To gain maximum amount of photosynthesis whilst still maintaining profit
REQUIRED PRACTICAL - pondweed
- Place a test tube rack containing a boiling tube 10 cm away from a light source
- Fill tube with fixed volume of sodium hydrogen carbonate solution
- Place a piece of cut pondweed submerged into tube
- Leave for 5 minutes acclimatise
- Start stopwatch and watch how many bubbles are produced in one minute
- For each light intensity, repeat 3x and calc a mean
- Repeat steps 1-7 for distances at 20cm, 30cm, 40cm
What are the 5 uses of glucose in photosynthesis?
- respiration
- converted into insoluble starch for storage
- produce fat/oil for storage
- produce cellulose for cell wall strength
- produce amino acids for protein synthesis
What is cellular respiration?
An exothermic reaction which is continuously occurring in living cells
Compare aerobic and anaerobic respiration
Aerobic - uses oxygen to transfer energy
Anaerobic - doesn’t use oxygen to transfer energy
What do organisms need energy for? Give 3 answers
- chemical reactions to build larger molecules
- movement
- keeping warm
What is the word equation for aerobic respiration?
glucose + oxygen –> carbon dioxide + water
What is the word equation for anaerobic respiration?
glucose –> lactic acid
Which of the 2 aerobic and anaerobic transfers more energy and why?
Aerobic - the oxidation of glucose is incomplete in aerobic respiration therefore much less energy is transferred than aerobic.
Anaerobic respiration equation in plant and yeast cells:
glucose –> ethanol + carbon dioxide
What is anaerobic respiration called in yeast cells?
Fermentation
What does fermentation have economic importance on?
- bread
- alcoholic drinks
During exercise, what does the body react to?
Increased demand for energy
What increases during exercise and why?
- heart rate, breathing rate, breath volume
- to supply muscles with more oxygenated blood
What takes place if insufficient oxygen is supplied and where?
Anaerobic respiration in muscles
