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Biology Edexcel A Alevel > Topic 5 > Flashcards

Topic 5 Flashcards

(79 cards)

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1
Q

Ecosystem

A

the interaction between living organisms and the environment in a given area.

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2
Q

Community

A

the interaction of different species in the same area

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3
Q

Population

A

members of the same species that occupy the same area

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4
Q

Habitat

A

Place where an organism lives

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5
Q

What 5 biotic factors effect the numbers and distribution of organisms

A 
competition for resources, 
grazing, 
predation, 
disease and parasitism 
mutualism
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6
Q

Name 5 abiotic factors that effect the numbers and distribution of organisms

A 
Solar energy input, 
climate, 
oxygen concentration, 
pollution 
catastrophe.
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7
Q

When are 2 species able to share the same habitat

A

Only if they occupy different niches

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8
Q

What happens if 2 species live in the same habitat and have exactly the same ecological niche

A

They will compete until the better adapted of the two outcompetes the other and excludes it from the habitat.

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9
Q

Mutualism

A

A relationship between two species in which both species benefit

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10
Q

What are the first organism to colonise bore surfaces

A

lichen

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11
Q

What is primary succession?

A

when there has never been a community before

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12
Q

What happens in colonisation

A

pioneer species colonise as they are the only organisms that can cope with extreme temperatures, lack of soil, water and nutrients.

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13
Q

What do pioneer species do?

A

they start to break up the rock surface which allows organic matter to accumulate, allowing a new species to join

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14
Q

what might cause the climax community to change

A

unless the conditions in the habitat changes the climax community is stable

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15
Q

what is a dominant species of a community?

A

the one that exerts an overriding influence over the rest of the plants etc. sometimes there is more than one and they are often the most abundant species.

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16
Q

what is secondary succession?

A

on bare soil where an existing community has been cleared eg ploughed field or a forest fire

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17
Q

what is often a feature of pioneer species?

A

seeds widely dispersed by wind, rapid growth, short life cycle and abundant seed production.

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18
Q

What is deflected succession?

A

when human activity causes a community to remain stable because it prevents succession from running its course

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19
Q

What is the equation for photosynthesis?

A

6CO2 + 6H2O ——> C6H12O6 + 6O2

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20
Q

what is the overall aim of photosynthesis

A

to split apart the strong bonds in water molecules, storing the hydrogen in a fuel (glucose) by combining it with carbon dioxide and releasing oxygen into the atmosphere.

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21
Q

How is energy stored in ATP

A

ADP + Phosphate ion join together forming ATP in water. To make ATP the phosphate ion must be separated from the water molecule which requires energy.

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22
Q

What is it called when ADP and phosphate join together?

A

Phosphorylation

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23
Q

What is it called when ADP and phosphate break apart?

A

Hydrolysis

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24
Q

How is energy released from ATP in water?

A

The 3rd phosphate ion becomes hydrated forming bonds with the surrounding water molecules. In which lots of energy is released.

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25
What is the structure of ATP
adenine, ribose, 3 phosphate groups
26
Where does the light dependent reaction take place?
Thylakoid membranes
27
Explain the stages of the light dependant reaction
#NAME?
28
What is used in the light independent reactions
carbon dioxide
29
What happens in the Calvin cycle
-CO2 combines with 5C compound RuBP and is catalysed by Rubisco -The 6C compound formed is unstable so breaks down into 2 GP molecules -GP is reduced using the hydrogen from reduced NADP and energy stored in ATP into GALP -2/12 GALPs formed create a 6C su
30
What are the products of the light independent reaction used for?
They are used by plants and animals in respiration and in the synthesis of new biological molecules eg polysaccharides, amino acids, lipids and nucleic acids.
31
What is the role of the outer membrane in a chloroplast?
permeable to CO2 and H2O
32
What is the role of the inner membrane in a chloroplast?
Regulate the passage of substances
33
What is the role of the stroma in a chloroplast?
light independent reaction occurs here
34
What is the role of a starch grain in a chloroplast?
stores the products of photosynthesis
35
What is the role of dna loop in a chloroplast?
contains genes for some of their proteins
36
What is the role of a granum in a chloroplast?
contains a stack of thylakoids
37
What is the role of thylakoid membranes in a chloroplast?
contains chlorophyll and electron carriers and is involved in light dependant reactions
38
What is the role of thylakoid space in a chloroplast?
contains enzymes for photolysis
39
How do you calculate net primary productivity
NPP = GPP - Plant Respiration
40
What is gross primary productivity?
The rate at which energy is incorporated into organic molecules by an ecosystem
41
What is net primary productivity?
The rate at which energy is transferred into the organic molecules that make up new plant biomass
42
What are 4 ways we can recognise that climate change is real?
CO2 levels, temperature records, pollen in peat bogs and dendrochronology
43
why do peat bogs highlight a changing climate?
peat is the accumulation of partially decayed organic matter. Pollen can be used to reconstruct the past climates.
44
Why is pollen useful
each plant has a distinctive type of pollen and pollen has a tough outer layer and are produced in vast amounts
45
How can our knowledge of dendrochronology tell us about past climates?
If a ring in a tree was bigger then the conditions for the tree were likely better
46
which is the most potent greenhouse gas
methane
47
How long does methane stay in the atmosphere?
it only stays in the atmosphere for 12 years before it reacts with oxygen to form CO2 and water
48
Why is methane harmful?
it absorbs more infrared radiation than a molecule f CO2 does
49
Why is it though that increased CO2 levels cause global warming?
There is a strong correlation between temperature and carbon dioxide concentration
50
How are global trends predicted?
Extrapolation- extending the line
51
What assumptions are made when we extrapolate
we have enough data to establish the trend accurately and that present trends continue
52
why might these models have limitations
Limited data, limited knowledge, changing trends, limitations of computers and failure to include all factors
53
What are the possible effects of climate change?
changing rainfall patterns and changing seasonal cycles
54
What impact of the effects of climate change might it have on plants and animals
distribution of species, altered development and life cycles
55
How might climate change impact the distribution of species?
Some species may benefit from the change in climate and become dominant while others may be lost due to competition.
56
How might climate change impact the development of plants?
For plants photosynthesis may initially be faster but eventually enzymes will no longer be at optimum and start to denature.
57
How might climate change impact the development and life cycle of animals
If environmental cues trigger their behaviour or development. Spawning and hatching and growth rates are most likely to be effected.
58
Why do reactions occur in enzymes slowly at low temperatures?
Enzymes and substrate have low kinetic energy so move slowly and do not collide often
59
What is it called where the rate of reaction is highest?
Optimum temperature
60
What happens once the temperature becomes too high?
The shape of its active site is lost and the enzyme substrate complex no longer forms as it is denatured.
61
What is the impact on plants if enzymes denature
Higher temp and lower soil moisture as the enzymes denature
62
How does evolution occur
Through gene mutation and natural selection
63
WHat is evolution
change in allele frequency over time
64
How is new evidence analysed by the science community?
Scientific journals, peer review process and scientific conferences.
65
What is proteomics
Study of proteins
66
What is genomics
the study of genomes (DNA)
67
What are the 4 methods proteomics and genomics?
DNA Hybridisation, DNA profiling, DNA and protein sequencing and DNA molecular clocks
68
What is crucial to speciation?
Reproductive isolation (some kind of isolating mechanism) that prevents successful interbreeding and prevents gene flow
69
What is allopatric speciation?
geographic isolation which results in speciation
70
What is sympatric speciation?
a species evolves into a new species without a physical barrier
71
What can influence conclusions about controversial issues?
They can be impacted by who is reaching those conclusions
72
How does photosynthesis impact the carbon cycle?
The reduction of CO2 into organic substance and the release of oxygen as a waste product
73
How does biomass impact the carbon cycle?
Plant material accounts for the majority of photosynthesis in the world
74
How does respiration impact the carbon cycle?
The oxidation of organic substance into simpler inorganic compounds such as COs and water
75
How does death and decay impact the carbon cycle?
CO2 is released during the breakdown by microbes
76
What are the 2 factors likely responsible for the carbon cycle not being in balance?
combustion of fossil fuels and deforestation
77
What 2 factors can we do to help maintain the balance?
Sustainable resources including biofuels and reforestation
78
How does using sustainable resources help manage the conflict between human needs and conservation?
They are renewable and carbon dioxide neutral
79
How does reforestation help manage the conflict between human needs and conservation?
Newly planted trees are rapidly growing and photosynthesising with little respiration so they are net absorbers.

Biology Edexcel A Alevel (15 decks)

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