B4: Bioenergetics Flashcards
Why are plants ‘producers’ in the food chain?
They are autotrophs, they can make their own food
Word equation for photosynthesis?
Carbon dioxide + water -(light and chlorophyll)- glucose + oxygen
Balanced symbol equation for photosynthesis?
6CO2 + 6H2O -(light and chlorophyll)- C6H12O6 + 6O2
Where does a plant get CO2 and water?
CO2- diffuses into the leaf through the stomata
Water: from the ground through the xylem into leaves
What are the four limiting factors of photosynthesis?
Temperature, carbon dioxide concentration, light, chlorophyll amount
What is the relationship between temperature and the rate of photosynthesis? Why?
The higher the temperature, the higher the rate of photosynthesis (direct proportion). This is because the higher the temperature, the more kinetic energy the particles have and more collisions!
What is the relationship between light intensity/ carbon dioxide and the rate of photosynthesis? Why?
The more co2/light, the higher the rate (direct proportion)
What would a graph of temperature and the rate of photosynthesis look like? What happens at the top?
A negative parabola? The enzymes denature at the top and the reaction cannot continue
What would a graph of co2/light and rate of photosynthesis look like? What happens at the top?
An increasing line then a plateau and a horizontal line. The rate becomes constant as the factors have reached their optimum
Why might a plant have less chlorophyll?
- magnesium deficiency or other nutrients
-tobacco mosaic virus or other diseases - loss of leaves
Relationship between light intensity and distance? Calculation?
Inversely proportional (as distance increases light decreases)
Inversely proportional square law : light intensity = 1/distance^2
What can a farmer do to a greenhouse to increase yield?
REQUIRED PRACTICAL: rate of photosynthesis (pondweed)
Method?
1) place pondweed into a beaker of water
2) use a light a set distance away from the beaker
3) record te number of bubbles in three minutes
4) repeat steps for different distances
REQUIRED PRACTICAL: rate of photosynthesis (pondweed)
Variables:
Independent: distance
Dependent: gas produces
Control: temperature, carbon dioxide
Use of glucose in plants? (6)
RESPIRATION: glucose is a substrate and used in respiration
CELLULOSE: cellulose strengthens cell wall
STARCH: starch is made of glucose polymers, it is stored in the plant as grains and is insoluble so wont affect osmosis
SUCROSE/FRUCTOSE: attracts animals to eat and germinate seeds
FATS AND OLIS: for extra energy storage, helps germination
AMINO ACIDS: Glucose + nitrates - amino acids -proteins
Is photosynthesis an endo or Exothermic reaction?
Endothermic
Is respiration an endo or Exothermic reaction?
Exothermic
Word equation for aerobic respiration
Glucose + oxygen - carbon dioxide + water
Symbol equation for aerobic respiration?
C6H12O6 + 6O2 - 6CO2 + 6H2O
Where does aerobic respiration take place?
Mitochondria
Word equation for anaerobic respiration in humans (and some bacterial cells)?
Glucose - lactic acid
Word equation for anaerobic respiration (fermentation) in plants and yeast?
Glucose - ethanol + carbon dioxide
Which respiration produces more energy and why?
Aerobic bc the glucose is fully
Broken down
What is the body’s reaction to more exercise?
- increased breathing rate and volume
-increased heart rate
What is oxygen debt?
The amount of extra oxygen the body needs after exercise to react with the accumulated lactic acid and remove it from all cells
What is metabolism?
The sum of all reactions in a cell or the body
