Topic 5 Flashcards
Define heterotrophic
Organisms generally eat plants or other animals which have eaten plants
Describe the structure of ATP
Nucleotide with 3 phosphate groups attached
Adenine
Ribose. P. P. P
When energy is needed what happens to ATP
The third phosphate bond can be broken by a hydrolysis reaction, catalysed by ATPase
Result- ADP and Pi and energy
Where does the energy come from to synthesise ATP from ADP
Comes from catabolic (breakdown) reactions or redox reactions
In a chloroplast what happens in the stroma?
Site of light-independent step
The stroma contains all the enzymes needed to complete photosynthesis
What happens in the grana
Site of light-dependent step
Describe the structure and use of the envelope in chloroplast molecules
Made from two layers of membrane, contains ATP synthase enzymes
Explain the electron transport chain
Hydrogen acceptors pick up hydrogen
The acceptor becomes reduced
Electrons passed along a series of carriers known as an ETC
The components of the chain are reduced when they receive the electrons and oxidised again when they pass them on
These redox reactions can release a small amount of energy which is used to drive synthesis of a molecule of ATP
Equation for photosynthesis
6co2 + 6H2O –> C6H12O6 + 6O2
What is the energy from the sun used for in photosynthesis
Energy used to split the strong H-O bond in water molecules
Hydrogen released is combined with co2 to for glucose, oxygen released as waste product
Describe the structure of a granum
Made up of stacks of membrane dics known as thylakoids
This is where the chlorophyll molecules are arranged on the membranes for trapping light energy
Describe chlorophyll, what 5 pigments make it up (give colours)
Chlorophyll Is a group of five closely related pigments:
Chlorophyll a (blue-green)
Chlorophyll b (yellow-green)
Carotenoids (orange carotene and yellow )
Phaephytin (grey)
Which pigment is most abundant in photosynthesising plants
Chlorophyll a
The other pigments are found in varying proportions
What do the photosynthetic pigments do? What is the advantage of having more than one pigment?
Absorb and capture light from particular areas of the spectrum
Far more of the energy from the light falling on the plant can be used than if only one pigment was involved
State 2 chlorophyll complexes and where they are found
Photosystem 1 lamellae
Photosystem 11 grana
Each contain a different combination of chlorophyll pigments and so absorb light in slightly different area of the spectrum. They are different sized particles attached to the membranes in the chloroplast
Describe what is involved in cyclic photophosphorylation
PsI
Light hits molecule, excited electrons leave. Taken up by electron acceptors and passed along ETC to produce ATP
What does non-cyclic photophosphorylation involve?
PsI and PSII
What electron acceptor accepts electrons from ps1
NADP –> reduced NADP
What are the advantages of using ATP as a power supply
ATP is regenerated therefore it doesn’t need to be stored
ATP is small and can pass in/out of cells easily
You can generate ATP in lots of different ways
What is the light- independent stage of photosynthesis
Calvin cycle takes place in the stroma of the chloroplast
Describe the steps of the Calvin cycle
Co2 from air combines with 5c compound (carbon dioxide fixed) Rubisco -rate limiting enzyme Form unstable 6c Splits to 3c Hydrogen added to form 2 Galp (H from reduced NADP)
Define habitat
Place where organisms live
Define population
A group of organisms of that same species living and breeding together in a habitat
Define community
All the populations of the different species of organisms living in a habitat at any one time
Define niche
The role of the organism in the community
Broken down into food niche or the habitats niche
Define abiotic factors
Give examples
Non- living elements of the habitat of an organism
Light Wind/water currents Water availability Soil structure/ mineral content Oxygen availability
Define biotic factors
Examples
Living elements of a habitat Predation Finding a mate Territory Parasitism/disease
Define autotrophic
Make organic compounds from carbon dioxide by photosynthesis
