Unit 4 Flashcards
(8 cards)
when light is absorbed by chlorophyll, it excites … (1 mark)
electrons
oxygen is produced when water molecules are split in the process of … (1 mark)
photolysis
the products of the light dependent reactions that are used in the light independent reactions are reduced NADP and … (1 mark)
ATP
describe the structures in a chloroplast that are involved in the light dependent reactions of photosynthesis (3 marks)
- thylakoids
- made of membranes
- arranged in circular piles/ stacks called grana
- photosynthetic pigments are held (chlorophyll pigments are contained in the grana, sandwiched between lipid and proteins of the thylakoid membrane)
- arranged as quantasomes/photosystems
suggest two advantages if growing crops in glasshouses with artificial lighting rather than growing them in open air (2 marks)
- crops can be grown out of season/ all year long
- plants photosynthesis 24 hours a day
- less physical damage from whether and animals
- easier pest control
- control of: carbon dioxide, humidity, temperature and water supply
explain how increases in carbon dioxide and methane, released into the atmosphere, may be contributing towards the estimated changes in mean temperature (3 marks)
- carbon dioxide and methane are both greenhouse gases
- they trap/ absorb heat/ infrared/ long wave radiation
- reflected from earth’s surface/ re-radiation
- mean temperature of earth’s surface increases
explain the difference between abiotic and biotic factors (1 mark)
- abiotic factors are the non living factors (physical and chemical environments)
- biotic factors are the living factors (predators, parasites ad disease causing organisms)
explain how a quadrat would be used to obtain the mean density of 2 species (3 marks)
- several/ many/ more than 2 reading
- use of random quadrat positions
- using a sequence of random numbers using a computer software (random number generator)
