B4 Bioenergetics Flashcards
(39 cards)
Word Equation for Photosynthesis
Water + carbon dioxide»_space; oxygen + glucose
Symbol Equation for photosynthesis
6H20 + 6CO2»_space; 6O2 + C6 H12 O6
Where does photosynthesis occur?
Chloroplast
Word Equation Aerobic respiration
Glucose + oxygen»_space; carbon dioxide + water
Symbol equation Aerobic Respiration
C6 H12 O2 + 6O2»_space; 6O2 + 6H2O
Where does aerobic respiration occur?
Mitochondria
Word equation anaerobic respiration in muscles
Glucose»_space; lactic acid
Word equation anaerobic respiration in yeast
Glucose»_space; ethanol + carbon dioxide
Where do both types of anaerobic respiration occur?
Cytoplasm
What happens to oxygen that plants produce?
Diffuses out of stomata as a waste product
Describe how guard cells close stomata
- Ions transported out of guard cells
- Water leaves guard cells by osmosis
- Reduces turgor
- Flaccid guard cells straighten
- Stoma closes
Describe how guard cells open stomata
- Ions transported into guard cells
- Water enters guard cells by osmosis
- Increases turgor
- Turgid guard cells curve
- Stoma opens
Why store glucose as starch?
It is insoluble rather than the soluble glucose that could be lost. Starch can be converted back when needed.
SCARF
5 uses of glucose in a plant
- Starch (as a store)
- Cellulose (for cell walls)
- Amino Acids (to make proteins & grow)
- Respiration (energy for this)
- Fats (as a store)
Limiting factors for photosynthesis
- Light intensity
- Temperature
- Carbon dioxide
- Chlorophyll
What is glucose combined with to make amino acids?
Glucose + NITRATE IONS»_space; amino acids»_space; proteins
Describe how rate of photosynthesis changes with light intensity
At the start, increasing light intensity increases the rate of photosynthesis (ROP)
Eventually, increasing light intensity stops increasing ROP
This means the ROP plateaus. It hasn’t stopped, it just stopped increasing!!
Describe how rate of photosynthesis changes with carbon dioxide concentration
At the start, increasing CO2 concentration increases the rate of photosynthesis (ROP)
Eventually, increasing CO2 concentration stops increasing ROP
This means the ROP plateaus. It hasn’t stopped, it just stopped increasing!!
Describe how rate of photosynthesis changes with temperature
At the start, there is not much
energy to catalyse the reaction
It peaks at the optimum temperature
The enzyme begins to denature and the ROP decreases
How to reduce light as a limiting factor to increase crop yields
- Greenhouses to enable maximum transition of light
- Artificial lighting with increased light intensity to provide optimum wavelength
These mean that the plant’s growing season is lengthened = more profit
These modifications to growing areas are commonly seen in illegal marijuana plants
How to reduce temperature as a limiting factor
- Greenhouses to trap heat inside
- Industrial greenhouses fitted with windows/vents to allow cooling
How to reduce water as a limiting factor
- Irrigation systems used to increase yields
- Plants sprayed with water to keep humidity high
reduces rate of transpiration, minimising water loss
Photosynthesis RPA Method
- Cut pondweed and secure it in a boiling tube, cut end up
- Add 20ml of Sodium Hydrogen Carbonate as a CO2 source
- Put in a beaker of water (heat protection)
- Ruler next to beaker. Lamp at set distance.
- Count bubbles in set time
- Move lamp back set distance and repeat for a mean
Improvements for Photosynthesis RPA
- Use LED bulb (heat not produced)
- Measure volume of oxygen with a gas syringe instead of counting bubbles
