Describe a pyramid of energy and the reasons for its shape.
Outline the conversion of light energy to chemical energy in photosynthesis.
Explain the conversion of the chemical energy of organic compounds into ATP in aerobic cell respiration.
Food miles are included in the calculation of the total energy input used to produce foods and transport them to the consumer. The daily per capita total energy input to the US food system was calculated to be - 23.1 kJ for fats, sugars, snacks and baked goods
State two problems caused by long distance food transport.
Discuss the impact on the environment and human health caused by the consumption of foods with high and low total energy input.
In a rock pool a student observes four different species of animal. She sees 43 flat periwinkles (Littorina littoralis), ten rough periwinkles (Littorina saxatilis), three shore crabs (Carcinus maenas) and one common goby (Pomatoschistus microps).
How many populations and communities did she see in the pool?
Populations | Communities | |
---|---|---|
A. | 1 | 4 |
B. | 2 | 3 |
C. | 3 | 2 |
D. | 4 | 1 |
Which is not essential in a viable mesocosm?
Every cell is surrounded by a cell surface membrane which regulates the movement of materials into and out of the cell.
Draw an annotated diagram of the fluid mosaic model of membrane structure.
Describe the processes involved in absorbing different nutrients across the cell membrane of villus epithelium cells lining the small intestine.
Explain the events that occur during a nerve impulse and how the impulse is propagated along an axon.
The Haberlea rhodopensis plant is capable of tolerating extreme dryness. Chlorophyll levels and CO2 assimilation were evaluated during dehydration and rehydration using plants grown in shade and sunlight. Graph A shows the changes in chlorophyll content with increasing dehydration and during rehydration. Graph B shows the changes in CO2 assimilation with increasing dehydration and during rehydration. Water content / % Water content / % Key: □ shade □ sunlight [Source: adapted from K Georgieva, et al., (2013), 15th International Conference on Photosynthesis, pages 536-542]
State the level of chlorophyll at 50% water content for plants growing in sunlight, giving the units.
Outline the effect of sunlight and shade on CO2 assimilation during dehydration.
Compare the effect of rehydration on chlorophyll levels in plants grown in shade and sunlight.
Using the data, deduce, with a reason, two stages of photosynthesis that may be limited during dehydration in a plant.
How do greenhouse gases contribute to global warming?
Which conditions favour peat formation?
Which excretory product occurs in which group of organisms?
Carbon dioxide | Uric acid | Oxygen | |
---|---|---|---|
A. | mammals | birds | plants |
B. | mammals | plants | birds |
C. | plants | mammals | birds |
D. | birds | plants | mammals |
The diagram shows interactions between food chains in an ecosystem in the African savannah.
[Source: © International Baccalaureate Organization 2018]
Which arrows indicate the flow of chemical energy?