Topic 5 Flashcards
Explain how abiotic factors influence a population
-Abiotic: light, water, space
-Ideal temperature leads to optimal metabolic rate, not much energy required to maintain body temperature
Explain niche
-The role a species has within a habitat
-E.g organisms it eats or is eaten by, O2 breathed in and CO2 out
-Only occupiable by one species, if there are 2 there will be slight differences - they will also compete leading to lower survival rate
Explain succession
-Process of ecosystem change, ecosystems are dynamic
-Primary succession: occurs on newly formed land, where bare rock only lays
-Secondary: occurs on land cleared of all plants but soil remains e.g after a forest fire or deforestation
Explain primary succession
-Occurs on newly formed land, where bare rock only lays
-Seeds/Spores e.g lichen are blown by wind and begin to grow (pioneer species)
-Abiotic factors are harsh, there are no soil to retain water, pioneer species grow due to their adaptations to the harsh enviroment
-Pioneer species changes the abiotic conditions, death and decay of their organic matter forms basic soil
-Conditions become less hostile, soil can retain water giving rise to new organisms to move in and grow which eventually dies and decays providing more soil and minerals, this repeats over time
-New species e.g grass moving in may change enviroment tailoring it less to previous species
-Small trees/shrubs begin to grow outcompeting previous species creating biodiversity
Explain secondary succession
-Occurs same way as primary however soil layer already exists
-Pioneer species would be shrubs or larger plants
-Each stage has different plants and animals with better adaptions outcompete the existing organisms and become dominant species
-As succession goes on, ecosystem becomes more complex and diverse
-Final stage is climax community, the ecosystem is large and barely changes over time
Explain photophosphorylation
Explain photolysis
Explain hydrolysis
Explain redox
-Addition of phosphate to a molecule using light
-Splitting of a molecule using light
-Splitting of a molecule using water
-Reduction = gain electrons e.g gain H or lose O
-Oxidation = lose electrons e.g lose H or gain O - always involves reduction of another molecule
Explain photosynthesis
-Process where energy from light is used to break apart bonds in H2O
-Hydrogen from breakdown is stored in glucose when formed with CO2
-O2 is released into the atmosphere
-6CO2 + 6H2O + Energy -> C6H12O6 + 6O2
-Energy is stored in glucose in plants until released by respiring
Explain ATP
-During respiration, glucose is broken down releasing energy to synthesise ATP via phosphorylation
-ATP synthase catalyses the reaction
-ATP diffuses to the part of cell requiring energy
Explain light-dependent reaction
-Needs light, occurs in thylakoid membrane of grana, produces ATP and NADP
-Products are used in LIDR to convert CO2 to glucose
-PS2 absorbs light, which excites electrons
-Electrons passes through ETC to PS1 via redox reactions, as it moves, the energy of them is used to produce ATP via chemiosmosis
-PS1 absorbs the light energy, electrons excite once again through another ETC producing ATP via chemiosmosis
-At the end of the ETC, in the stroma, the electron pair adds to NADP forming reduced NADP
-Energy from light has produced ATP (photophosphorylation), PS2 has a net loss of 2 electrons
-Enzyme in PS2 splits water using light energy (photolysis) producing O2 + 2e which replaces the lost electrons in PS2
Explain how ETC works
-As electron pair moves through, energy of electrons pump H+ ions from stroma into the thylakoid membrane
-Thylakoid membrane is impermeable to protons therefore H+ ions cannot diffuse back
-Creating a greater concentration inside the thylakoid membrane than stroma named the electrochemical / proton gradient
-This gradient is enhanced for when NADP is converted to reduced NADP, using a H+ ion from the stroma decreasing its proton concentration outside the thylakoid membrane
-Also when photolysis of water occurs, 2e and O2 is produced with 2H+ inside the thylakoid membrane
-Inside the thylakoid, ATP Synthase provides a channel for ions to move into the stroma, the movement of these ions allows the enzyme to produce ATP from ADP + Pi (this is chemiosmosis)
Explain chemiosmosis
-Inside the thylakoid, ATP Synthase provides a channel for H protons to move into the stroma, the movement of these protons allows the enzyme to produce ATP from ADP + Pi
-Movment of protons helps form a greater proton gradient inside the stroma than thylakoid
Explain light-independent reaction / calvin cycle
-Cycle which occurs in stroma
-Uses ATP and reduced NADP frem LDR for CO2 (1C) to make into glucose
-1) Fixation: -Cycle which occurs in stroma
1C CO2 reacts with 5C RuBP cataylsed by Rubisco to make 2x GP (3C)
2) Reduction: 2x GP (3C) is reduced into 2x GALP (3C) using reduced NADP -> NADP for Hydrogen and ATP -> ADP + Pi for energy
-GALP can be removed for the plant to make glucose or other molecules like amino acids
-1C will stay on the side for the cycle to make 5 more C for glucose
-3) Regeneration: RuBP (5C) is regenerated using ATP -> ADP + Pi on GALP (3C) allowing the cycle to continue
-CO2 is 1C, glucose is 6C - the cycle must occur 6 times to make glucose from CO2
What can be made from products of LIDR
-Carbs: joining 2 GALP
-Lipids: made using glycerol, synthesised by GALP
-Lipids: fatty acids synthesised from GP
-Amino acids: some are made from GP
-Nucleic Acids: Sugar in RNA (ribose) made using GALP
Explain energy transfer through an ecosystem
-Plants are primary producer, energy through photosynthesis
-Producers store sunlight energy as biomass
-Energy is transferred through the eating of living organisms.
-Producers are eaten by organisms named primary consumer
-Primary consumer is eaten by secondary and then tertiary
-Not all energy is transferred, energy loss due to respiration
Explain why not all energy is transferred to the next trophic level
-90% of all energy is lost in various ways
-Plants reflect or fail to absorb light due to light hitting the root which is unable to photosynthesise
-Some foods are not fully eaten e.g bone so energy go to decomposers
-30% of total energy available is lost to enviroment e.g by respiring for movement or body heat
-10% become biomass, this is named the net productivity aka energy available to the next throphic level
-GPP = NPP - R
