Biology - Unit 4 Flashcards
What are photoautotrophs?
Organisms which make organic molecules using light energy
What are chemoautotrophs?
Organisms which make organic molecules using chemical energy
What are heterotrophs?
Organisms which rely on ready-made energy-storing organic molecules from other organisms
Where does the light dependent reaction take place?
Thylakoid membrane site
Where does the light independent reaction take place?
Stroma
What is the Rf value of a pigment?
Distance moved by pigment/Distance moved by solvent
What are the names of the five pigments in chlorophyll?
Beta carotene Phaeophytin Xanthophyll Chlorophyll a Chlorophyll b
What occurs in photoexcitation?
Electrons get excited by light and move away from molecule
What occurs in photoionisation?
Electrons get too excited by light and leave the molecule
What is the method of cyclic photophosphorylation?
Electron in PS1 excited by light
Electron passed down ETC generating ATP
What wavelength of light does PS1 absorb?
700
What wavelength of light does PS2 absorb?
680
What does cyclic photophosphorylation produce?
ATP
What is the method of non-cyclic photophosphorylation?
Water splits in to proton and hydroxide ion
Oxygen produced and electron passed on
Electron enters PS2
PS2 hit by light and electron passed onto electron acceptor
Electron passed down ETC into PS1 producing ATP
PS1 hit by light and electron excited into NADP
Proton from the water accepted by NADP to form reduced NADP
What occurs in the Calvin Cycle?
GALP turned into RuBP
Reaction between RuBP and carbon dioxide catalysed by RUBISCO to produce a 6-carbon compound
6C compound splits into 2 molecules of GP
NADP formed and ATP broken up to form 2 GALP molecules
Some GALP used to produce amino acids and glucose and some fed back into the cycle
What is ecology?
The study of the interactions that determine the distribution and abundance of organisms within a particular environment
What is a habitat?
The place where an organism lives
What is a population?
A group of organisms of the same species, living and breeding together in a habitat
What is a community?
All the populations of the different species of organisms living in a habitat at any one time
What is a niche?
The role of an organism in its community
What are abiotic factors?
The non-living elements of the habitat of an organism
What are biotic factors?
The living elements of a habitat which affect the ability of a group of organisms to survive there
What is the process of primary succession?
Empty inorganic surface Opportunists - Lichens, algae, mosses Rock broken into grains to form humus Grasses and ferns establish root systems Death and decay adds nutrients Larger species supported
What is a climax community?
Where the biodiversity and range of species is generally constant
What is the process of secondary succession?
Bare earth, grass, weeds Grass stage Grass and shrubs Young forest Mature forest
What is a plagioclimax?
A final community which is partially the result of human intervention
What are examples of abiotic factors?
Light Temperature Wind and water currents Water availability Oxygen availability Edaphic factors - Soil structure and mineral content
What are examples of biotic factors?
Predation Finding a mate Territory Parasitism and disease Competition
What is the effect of light on organisms?
Plants are dependent on light for photosynthesis
Plants in low light levels need adaptations to cope - Earlier reproduction, Extra chlorophyll
Animals are affected as a result of plant distribution
What is the effect of temperature on organisms?
Range of temperature in which an organism can grow and successfully reproduce
Extremes not average determine habitat
Many animals have adaptations to cope
What is the effect of wind and water currents on organisms?
Wind increases heat and water loss
Less likely to survive in strong winds
Habitats can be destroyed
In water currents, have to flow with the current, be strong swimmers or hang on tight
Can be sudden increase due to flooding
What is the effect of water availability on organisms?
Affected by amount of precipitation, rate of evaporation and edaphic factors like loss through drainage
Can die if not adapted and severe water stress
Sudden increase can lead to a huge habitat change so population sizes increase
What is the effect of oxygen availability on organisms?
When water is cold or fast flowing, sufficient oxygen dissolves in it
If warmer or still and stagnant, oxygen content drops
In waterlogged soil, there is little oxygen
Some plants have adaptations to cope in waterlogged conditions
What is the effect of edaphic factors like soil structure and mineral content on organisms?
Sand has a loose, shifting structure
Can only grow on it if adapted
Soils with lots of sand are light and easily worked and warmed but drain easily
Leaching of minerals occurs when water is easily drained
Ideal soil has particles of varying sizes
What is the predator-prey cycle?
Prey population increases
More food so predator numbers increase
Therefore, prey numbers decrease
Predator numbers decrease
What is the effect of finding a mate on organisms?
Abundancy of a type of animal will increase with availability of a mate
What is the effect of territory on organisms?
Territories normally used to ensure a breeding pair has sufficient resources
Type and size of territory determines species
What is the effect of parasitism and disease on organisms?
Diseased animals are weakened and often unable to reproduce successfully
Sick predators less likely to catch prey
Sick prey more likely to get caught
Parasites more likely when population density is higher
What is intraspecific competition and what are possible results of it?
Competition for a limited resource between members of the same population or species
Results:
-Some individuals may not survive or reproduce, slowing population growth
-If sufficient resources, there will be little competition so population growth maximises
What is interspecific competition and what are possible results of it?
Different species within a community compete for the same resources
Results:
-Reduced abundancy of a species
-Possible exctinction
What is Gross primary productivity (GPP)?
The rate at which energy is incorporated into plants
What is net primary productivity (NPP)?
Energy stored in body tissues
GPP - plant respiration
Describe the carbon cycle in nature
Carbon dioxide removed by photosynthesis
Added in organically by respiration of plants, animals and decomposers
Added in inorganically by fossil fuel combustion and weathering of carbonate rocks
What is used as evidence of global warming?
Drilling into ice and taking ice cores
Dendrochronology
Peat bogs - Looking at pollen grains in it
What factors affect the ability for oceans to be efficient carbon sinks?
Water temperature and ocean currents
What is proteomics?
The study of proteomes
What is a proteome?
All the proteins produced from a genome