Topic 5 - On the Wild Side Flashcards
What is a Light-Dependent Reaction?
Using light and hydrogen energy from photolysis to produce reduced NADP and ATP
What is a Light-Independent Reaction?
Uses reduced NADP and ATP to reduce CO2 to carbohydrates
What is Predation?
The relationship between organisms in which one benefits and feeds off of the other
What is a Population?
A group of organisms living in the same area belonging to the same species with the ability to interbreed
What is a Community?
A group of organisms living in the same area, all belonging to different species
What are the Different Abiotic Factors?
- Solar Energy Input
- Climate
- Topography
How is Solar Energy Input Effected?
- Latitude
- Season
- Cloud Cover
(Viral for photosynthesis and acts as an environmental cue for reproduction)
What is Topography?
The slope of land and it’s drainage
What is an Edaphic Factor?
Factors associated with soil pH and the mineral concentration
What is Mutualism?
A relationship between species where both partners benefit.
E.g humans and digestive bacteria
What is a Density Dependent Biotic Factor?
Where the effects depend on the population density. (E.g the larger the population density, the greater the competition between species)
What is an Anthropogenic Factor?
Abiotic or biotic factors that occur because of human activity
What is Primary Succession?
When new habitats form where there has never before been a community
What is Secondary Succession?
When habitats form where an existing community has been cleared
What are Pioneer Species?
The first species to colonise the forming habitat. They can usually cope with extreme conditions (e.g lack of soil or water)
What is a Climax Community?
Usually dominated by trees, this is a stable community that is achieved in succession and is usually unchanged
What is Deflected Succession?
A form of succession that remains stable because of human activity
What is Primary Productivity?
The rate in which energy is transferred into organic molecules in an ecosystem
What is an Autotroph?
Also known as a producer, these are organisms that make their own organic compounds
What is a Chemosynthetic Autotroph?
Organisms that make organic molecules from chemical reactions instead of light
What is Photolysis?
The splitting of water, using light energy
How is Hydrogen Stored in Carbohydrates?
Hydrogen and CO2 react and the CO2 is reduced to form glucose
Why is Photosynthesis Important?
- Animals can’t make all organic molecules so are dependent on the plants
- Oxygen is released so that organisms can anaerobically respire
What is the Thylakoid Membrane?
- System of flattened sacs
- Proteins and electron carriers are stored here
What is a Thylakoid Space?
- The fluid within the thylakoid membrane
- Contains enzymes for photolysis
What is the Stroma?
- Fluid surrounding thylakoid membranes
- Contains all enzymes for light-dependent reactions
What is a Starch Grain?
Stores photosynthesis products
What is a Granum?
Stack of thylakoids
What is the Inner Membrane of a Chlorophyll Molecule?
Contains transporter molecules which regulate passage of substances
Explain the Process of the Light-Dependent Reaction?
- Light energy raises 2 electrons in each chlorophyll
- Electrons become ‘excited’
- Electrons travel through electron carriers in electron transport chain
- PSII electrons pass through oxidation/reduction reactions and lose energy as they do so
- Lost energy used to make ATP
- Lost electrons are replaced
- Photolysis occurs to create O2, H and electrons
What is the Name of the Process That Makes ATP in Photosynthesis?
Photophosphorylation
What is the Structure of ATP Made Up Of?
- Adenine (organic base)
- Ribose (sugar)
- 3 phosphate groups
What Happens When the 3rd Phosphate Group in ATP is Removed?
It becomes hydrated and bonds with surrounding water molecules
How is ATP Produced?
From ADP and an inorganic phosphate
Where does the Light-Independent Reaction Occur?
Stroma in the chloroplast
Where Does the Light-Dependent Reaction Occur?
Thylakoid Membrane in the Chloroplast
Explain the Process of the Light-Independent Reaction?
- CO2 combines with 5C compound (RuBP)
- This is catalysed by RuBISCO
- 6C compound breaks down into X2 3C compound (GP)
- 3C compound is reduced, forming sugar phosphate (GALP)
- (For reduction, H from LD reaction used and ATP provides energy)
- GALP forms 6C sugar (hexose) or recreates RuBP for repeat of cycle
- Hexose can convert into amino acids/lipids
What is Carbon Fixation?
When inorganic carbon in CO2is converted to organic molecules
What is a Trophic Level?
The position of a species in the food chain
What is a Primary Consumer?
A herbivore
What is a Secondary Consumer?
Carnivores (feed on Primary consumers)
What is a Tertiary Consumer?
Carnivores at the top of the food chain (also known as top carnivores)
What is a Food Web?
A system of interlocking food chains in an ecosystem
What is a Detritivore?
Primary consumers that feed in dead organic material (e.g woodlice and earthworms)
What are Decomposers?
Bacteria and fungi species that feed on remains of dead organisms
Why is Only a Small Amount if Light Absorbed in Photosynthesis?
Because chlorophyll can only absorb certain wavelengths
What are the Limiting Factors of Photosynthesis?
- Light Intensity
- Temperature
- CO2 concentration
What is Gross Primary Productivity (GPP)?
The rate that energy is incorporated into organic molecules by an ecosystem
How is the Percentage Efficiency of Photosynthesis Calculated?
GPP divided by light energy arriving at plant X 100
