Topic 5: On the Wild Side Flashcards
(82 cards)
1
Q
define habitat
A
the place where an organism lives
2
Q
define population
A
organisms of the same species living in a habitat
3
Q
define community
A
all the different populations of different species living in a habitat
4
Q
define niche
A
the role an organism plays in a habitat
5
Q
define abiotic
A
non-living elements of an organisms habitat
6
Q
define biotic
A
the living elements of an organism’s habitat
7
Q
define succession
A
the process by which communities of organisms colonise an area, then over time, are replaced by others that are usually more varied
8
Q
define ecosystem
A
the interaction of living organisms with abiotic factors
9
Q
give examples of biotic factors and their influence
A
new predators - in a balanced ecosystem predators catch enough prey to survive but not so much that they wipe out a population but a new predator could cause imbalance
competition - if two species compete for one resource and one is better adapted, the other will decrease in size until there are too few to successfully breed
new pathogens - the populations living in an ecosystem would likely have no immunity or resistance and their population would likely decrease or die out
10
Q
give examples of abiotic factors and their influence
A
light intensity - more light increases rate of photosynthesis, increasing rate of growth
carbon dioxide concentration - photosynthesis rate increases with more CO2, increasing rate of growth
soil pH - affects enzymes
can add
11
Q
describe primary succession
A
- pioneer species colonises bare land; seeds and spores are blown in by the wind and begin to grow
- harsh abiotic conditions eg. no soil for water retention, only pioneer species can survive
- pioneers change the conditions by dying and microorganisms decompose the humus to form soil and roots stop existing land from getting blown away
- less hostile conditions and the basic soil can retain water, grasses and small plants adapted to shallow/nutrient-poor soil arrive, their roots form a network to keep the soil in place
- new species change the env. and make it less suitable for the previous species
- soil becomes deeper and more nutrient-dense, biodiversity increases
- the final species to colonise becomes the dominant species, forming a climax community
12
Q
outline secondary succession
A
as there is already a soil layer, it starts at a later stage to primary succession
the pioneer species in secondary succession are larger plants
13
Q
what is the equation for photosynthesis
A
6CO2 + 6H2O –> C6H12O6 + 6O2
14
Q
define phosphorylation
A
adding phosphate to a molecule
ADP is phosphorylated to ATP
15
Q
define photophosphorylation
A
adding phosphate to a molecule using light
16
Q
define photolysis
A
the splitting of a molecule using light energy
17
Q
define hydrolysis
A
the splitting of a molecule using water, ATP is hydrolysed to ADP
18
Q
how is ATP used as an energy source in cells
A
- cells can’t directly get energy from glucose, so it is broken down in respiration, releasing energy to photophosphorylate ADP, forming ATP
- this reaction is catalysed by ATP synthase and the energy is stored as chemical energy in the phosphate bond
- ATP diffuses to the part of the cell that needs energy and is broken down back into ADP and inorganic phosphate via hydrolysis, releasing chemical energy from the phosphate bonds to be used by the cell - the reaction is catalysed by ATPase
the ADP and inorganic phosphate are recycled and the process restarts
19
Q
label this chloroplast
A
20
Q
what is the structure and function of the chloroplast envelope
A
it is a double membrane that helps to keep the reactants for photosynthesis close to their reaction sites
21
Q
what is the structure and function of thylakoids
A
they are filled with ATP synthase and have a large surface area to allow as much light energy to be absorbed as possible
they are stacked into grana to have a large surface area and absorb max light
22
Q
what is the structure and function of a thylakoid membrane
A
they contain photosynthetic pigments and chlorophyll that can absorb various wavelengths of light, the pigments are attached to proteins and collectively called a photosystem
there are 2 photosystems: photosystem I and photosystem II
23
Q
what is the structure and function of the stroma
A
it is a gel -like substance surrounding the thylakoids that contains all enzymes, sugars and organic acids required for the light independent reaction to take place
24
Q
outline the light-dependent reaction in photosynthesis
A
it needs light energy and takes place in the thylakoid membranes of chloroplasts
photosynthetic pigments in photosystems absorb light energy and convert it to chemical energy
- Light energy excites electrons in the chlorophyll to a higher energy level
- electrons release energy as they are passed along the electron transport chain
- energy released is used to pump hydrogen ions across the thylakoid membrane, which then diffuse back again via ATP synthase, adding an inorganic phosphate group to ADP, forming ATP via photophosphorylation
- light energy splits water into protons (H+), electrons and oxygen
- the electrons are used in the ETC
- NADP is reduced to form reduced NADP
ATP transfers energy and reduced NADP transfers hydrogen to the light-independent reaction
25
what products of the light-dependent reaction are used in the light-independent reaction in photosynthesis
ATP and reduced NADP from the light-dependent reaction supply the energy and hydrogen to make glucose from CO2
26
does the light dependent or independent reaction include photophosphorylation
the light dependent reaction
it includes two types; cyclic and non-cyclic
both processes produce different products
cyclic - ATP
non-cyclic - ATP and reduced NADP
27
explain non-cyclic photophosphorylation
1. light energy is absorbed by PSII, it excited electrons in chlorophyll making them move to a higher energy level
the high energy electrons then move along the electron transport chain to PSI
2. the electrons that leave PSII and move along the electron transport chain have to be replaced
light energy splits water into protons (H+ ions) and oxygen ; this is photolysis
reaction: H2O --> 2H+ + 2e- + 0.5O2
3. as the excited electrons move along the electron transport chain, they lose energy
the energy is used to transport protons into thylakoids so the thylakoid has a higher proton concentration that the stroma; forming a proton gradient across the membrane
protons move down this concentration gradient into the stroma via ATP synthase (enzyme)
the energy from this movement combines ADP and inorganic phosphate to form ATP
4. light energy is absorbed by PSI, exciting the electrons again to an even higher energy level
the electrons are transferred to NADP along with a proton (H+) from the stroma, to form **reduced NADP**
add revision guide pics or toher
28
explain cyclic photophosphorylation
uses only PSI
- light hits PSI and electrons are excited to a higher energy level and leave the photosystem
these move along the electron transport system, releasing energy as they do so
- this energy released allows H+ ions to be actively transferred from a low concentration in the stroma to a high concentration in the thylakoid membrane
- H+ ions diffuse back across the thylakoid membrane into the stroma via ATP synthase enzymes embedded in the membrane
- The movement of H+ ions cause the ATP synthase enzyme to catalyse the production of ATP
- the electrons rejoin PSI at the end of the electron transport chain
29
what is chemiosmosis
the process where the movement of H+ ions across a membrane generates ATP, it occurs in photosynthesis and respiration
30
what organic substances are made by the products of the calvin cycle
carbohydrates
lipids
amino acids
nucleic acids
31
how are carbohydrates made from the products of the calvin cycle
simple sugars like glucose - made by joining two GALP molecules
polysaccharides like starch/cellulose - made by joining hexose sugars together in different ways
32
how are lipids made from the products of the calvin cycle
GP is synthesised to form fatty acids
GALP is synthesised to form gLycerol
lipids are then made from glycerol and fatty acids
33
how are amino acids made from the products of the calvin cycle
they can be made from GP
34
how are nucleic acids made from the products of the calvin cycle
the sugar in RNA (ribose) is made using GALP
GALP is also used to make DNA
35
what is the calvin cycle also known as
light independent reaction
carbon dioxide fixation
36
outline the calvin cycle
1. CO2 enters leaf via stomata and diffuses into chloroplasts Stroma
CO2 combines with RuBP (5C) (ribulose bisphosphate) and this is catalysed by the enzyme RUBISCO to form an unstable 6C
this quickly breaks down into 2 lots of GP (glycerate 3-phosphate), a 3C compound
2. 2ATP (from the light dependent reaction) is hydrolysed and NADPH is used to get H to turn GP into GALP, both of which as 3C compounds
some GALP —> converted to useful organic compounds eg. glucose
some GALP —> continues in calvin cycle to regenerate RuBP
3. there are 2 GALP molecules with 6C overall
5C/6C are used to regenerate RuBP using ATP
so only 1C is left to make glucose
so 1/6 of a glucose molecule is produced every Calvin Cycle turn
which means 6 turns = 1 glucose molecule
37
what is a producer
the first trophic level in a food chain because it produces it's own food
38
define biomass
the mass of living material in an organism, it's what gets passed on between trophic levels
39
why is not all sunlight used by plants for photosynthesis
some light may be:
- wrong wavelength
- reflected off the leaf
- transmitted through the leaf
- hit a part of the leaf that can't photosynthesise
40
define net primary productivity (NPP)
the biomass, it is what the producer passes on to the primary consumer
41
what is gross primary productivity (GPP)
the quantity of energy that an organism takes in, some of which is lost in plant respiration
42
what is the calculation for net primary productivity
NPP = GPP - respiratory loss
43
why is not all energy from an animal passed on to the next trophic level
not all parts are consumed and some can't be digested ; eg. bones/ tendons and ligaments
some of the energy of the animal would have been used for it's own metabolic processes like respiration
44
what is the calculation for net productivity and when is it used
net productivity = gross productivity - respiratory loss
with animals
45
define climate change
the change in weather patterns in a particular area over a period of time eg. more monsoons/ global warming/ changing rainfall patterns
46
outline dendrochronology and how it’s used
dendrochronology - method of assessing a tree’s age by using it’s tree ring
scientists take cores through tree trunks and date each ring by counting back from when the core was taken
the thickness of the rings indicate the climate; a thicker ring means better climate
eg. warmer/less wind/light rain etc.
47
outline pollen in peat bogs and how it’s used
pollen is often preserved in peat bogs (due to the acidity and anaerobic nature), the bogs accumulate in layers so the age of preserved pollen increases with depth
1. scientists take cores from peat bogs and extract pollen grains from differently aged layers
2. they identify the plan species the pollen came from
only mature plant species produce pollen so samples only show the successful species from that time
3. the species is then compared to the climate that the species thrives in today
4. this is thought to be the climate at that time
48
how have temperature records been kept
since the 1850's temperature has been measures worldwide using thermometers
gives a reliable, short-term record of climate change
49
define species
a group of organisms with similar physiological features that can breed together to produce fertile offspring
50
how can plants use hexose sugars
- be respired to release energy
- convert into starch for storage
- convert into cellulose for cell wall structure
- convert into sucrose for transport
51
how can dendrochronologists learn about the climate going beyond the lifespan of living/recently chopped trees
examine fossilised trees
examine ancient objects made of wood eg. building parts/ furniture
52
what are ice cores and how are they used
ice forms from the compaction of snow, so it contains tiny bubbles of air from the era when it was formed
The gas content of the trapped air bubbles can be analysed for gas content and compared to the present-day atmosphere
53
why has ocean warming increased carbon dioxide
because it's less soluble in warm water than cold water
54
why might a woman piece of data be bad or not good to use for a future trend etc.
- only one set of data (reference location, species etc.)
- no statistical tests to see if the results were significant
- error bars not present
- no mean so no repeats
- not enough data collected
- fluctuation
- can’t assume a trend would continue
55
why is peer review important in science
- determine whether the research falls within the scope of the (scientific) journal being submitted to
- ensure experiment is repeatable
- check results were analysed appropriately
- prevent the publication of flawed scientific research
56
how do you calculate efficiency of biomass transfer
Efficiency of biomass transfer = (biomass transferred/biomass intake) x 100
aka biomass of B/biomass of A
57
why does more of the sun's radiation reach the earth than goes back into space
Shortwave radiation reaches Earth, longwave radiation is re-emitted by Earth
- Very little shortwave radiation from the sun is absorbed by greenhouse gases in Earth's atmosphere
- Most of the re-emitted longwave radiation is absorbed by greenhouse gases
58
sources of greenhouse gases
- cattle farming
- respiration
- peat bog degradation
- use of artificial fertilisers
59
how do greenhouse gases affect the climate
they trap infrared radiation/heat energy in the atmosphere, causing temperatures to increase
60
what is Q10 temperature coefficient
the ratio of the rate of an enzyme reaction taking place at two temperature differing by 10˚C/K
higher/lower
61
how can forests be managed sustainably
- replace trees that are cut down with rapidly growing trees
- cut down the older trees
62
what is the consequence of chopping down trees
- less photosynthesis, so less CO2 is fixed and more is in atmosphere
- CO2 is a greenhouse gas, so more infrared radiation will be trapped in the atmosphere, increasing temperatures
63
is CO2 reduced/oxidised in photosynthesis
CO2 is reduced to form organic molecules
64
where is chlorophyll found in a chloroplast?
in the thylakoid membrane
65
outline how you could study the Hill reaction
Hill reaction: PSI in LDR NADP is reduced and O2 is released from water
1. cut some leaves (eg. spinach) into pieces, removing any tough stalks
2. using a pestle and mortar, grind the leaf pieces up with some chilled isolation solution (sucrose, KCl, phosphate buffer, pH7)
3. filter the liquid into a beak via a funnel lined with muslin cloth, transfer the liquid to centrifuge tubes and centrifuge at high speed for 10 minutes to allow chloroplasts to gather at the base of each tube in a 'pellet'
4. get rid of the liquid at the top, leaving the pellets at the bottom. re-suspend the pellets in a fresh, chilled isolation solution - this is the chloroplast extract and should now always be stored on ice
5. set up a colorimeter with a red-filter and zero it with a cuvette containing the extract and distilled water
6. set up a test tube rack at a set distance from a bench lap and switch on the lamp
7. put a test tube in the rack, add a set volume of chloroplast extract and DCPIP, mix together
8. take a sample and add to a clean cuvette immediately, measuring absorbance with the colorimeter
9. repeat every 2 minutes for the next 10 minutes
10. repeat experiment 2x more, controlling distance from light, time etc.
66
explain the results that should be seen from the Hill reaction cp
The hill reaction occurs in photosystem I, during the light dependent stage of photosynthesis where NADP acts as a proton acceptor from split water, forming NADPH and O2 is released
the rate of this reaction can be investigated using a redox indicator dye (eg. DCPIP) to isolated chloroplasts
the dye can act like NADP and act as an e- acceptor, getting reduced
the reduction of the dye will show a colour change (DCPIP goes blue --> colourless); the rate of colour change can be measured to calculate the rate of the hill reaction
a graph of absorbance against time can help to visualise these results
67
how could the effect of temperature on seedling growth rate be studied
1. last seedlings of the same species and age in soil trays, measuring the height of each
2. put the trays in incubators at different temps
3. ensure other variables are controlled (water content of soil, light intensity, CO2 conc etc.)
4. after a period of incubation record the change in height of each seedling
5. calculate the average growth rate by doing: avg seedling height change / incubation period
68
how could the effect of temperature on brine shrimp hatch rate be studied
1. put an equal number of brine shrimp eggs in water baths at diff temps (10, 20...)
2. control all other variables in each water bath (water volume, salinity, O2 conc)
3. record the no. of hatched brine shrimp every 5 hrs
4. calculate hatching rate using
no. hatched brine shrimp water bath / number of hours
69
how can the effect of temperature on enzyme catalysed reactions be studied
1. set up boiling tubes with the same volume and concentration of hydrogen peroxide, adding equal volumes of a suitable buffer solution to each tube
2. set up the apparatus as shown in the diagram
3. put each boiling tube in a water bath (10, 20, 30 etc.) along with another tube containing catalase
4. add the same volume and conc of catalyse t each boiling tube, quickly attaching the bung and delivery tube
5. record the O2 produced every 10 seconds in the first minute, using a stopwatch to measure time
plot a graph and draw a tangent at 0 to get initial rate!!!
70
outline transects and how they're used
belt transect: data is collected along the transect, using frame quadrants placed next to each other
71
outline how climate change could be reduced
biofuels:
fuels made from biomass (material that is/was recently living) eg. crops
they are a sustainable resource and when they are burnt they don't increase atmospheric CO2 concentration
reforestation:
CO2 is fixated into carbon compounds and stored in trees as plant tissues
72
how might people disagree on methods of reducing climate change
biofuels:
famers might support because governments might fund crop farming for them
drivers might support because bio-fuels can be cheaper than oil-based
consumers might oppose because using farmland for fuel could cause food shortage
conservationists might oppose because forests have been cleared to grow biofuel crops
73
outline how you would study various abiotic factors in a given habitat
**climate**: temperature using a thermometer
**oxygen availability**: (only done in aquatic habitats) an oxygen sensor can measure the amount of O2 dissolved in the water
**solar input**: light sensor
**edaphic factors** (soil conditions): mix a sample of soil with water and a pH indicator solution
**topography**: measure relief using height reading at different points using a GPS
74
why is a cold buffer solution and sucrose used in studying the hill reaction
cold and buffer stops enzyme denaturation
sucrose stops osmotic water loss from chloroplasts
75
is NADPH formed in cyclic or non-cyclic photophosphorylation
non-cyclic
sooooo **N**on-cyclic = **N**ADPH
76
what should you mention when talking about glucose --> starch
forming glycosidic bonds between glucose molecules via condensation reactions
77
where does the light dependant vs independent reaction take place
dependent: thylakoids
independent: stroma
78
why is CO2 linked to plant growth
CO2 is fixed to produced GALP which is used to form carbs etc. this leads to increased growth ratw
79
outline a method to study the species' present in two different areas
- randomly generated coordinates via random no. generator
- quadrat 10 times MINIMUM in each place
- count the species in each quadrat
- calculate the total species in the given area
- calculate mean and standard deviation for each one
80
why do plants have less net emissions than meat
they **remove** CO2 from the atmosphere and use it to produce organic compounds via photosynthesis
animals respire more than plants and sometimes produce methane
81
why is deforestation bad
cuts down trees which are carbon sinks
burning of these trees releases CO2 into the atmosphere
without trees there’s less photosynthesis to remove CO2 from the atmosphere
82
how do pioneer species change bare rock
eg. lichens
help to slowly brew apart the surface and the fragmented rock plus the humus after the plant dies forms a basic soil layer
