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  • Created by: hatty101
  • Created on: 11-06-14 19:23
Compare the biodiversity of natural and artificial ecosytems
The biodiversity in natural ecosystems is higher than artifical ecosytems
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Recall the balanced symbol equation for photosynthesis
6CO2 + 6H2O --> C6H12O6 + 6O2
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Explain why plants carry out respiration at all times
Plants are living organisms so need to respire and release energy at all times
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Name the main parts of a leaf
Cuticle, upper & lower epidermis, spongy mesophyll cells and palisade cells
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Explain how leaf cells are adapted for photosynthesis
Epidermis is transparent so light passes through; upper palisade layer contains most of leaf's chloroplasts so it receives most light; mesophyll cells are loosely spaced so diffusion takes places and has large surface area so gas can enter and exit
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Explain the net movement of particles in diffusion
Move from high concentration to low concentration as a consequence from random movement of particles
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Describe the process of osmosis
Movement of water across a partially-permeable membrane from a high water concentration to low water concentration
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What is transpiration
The evaporation and diffusion of water from inside leaves
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Explain why plants need nitrates, phosphates, potassium and magnesium
Nitrates: to produce amino acids to provide protein for cell growth | Phosphates: to make DNA and cell membrane, involved in respiration and growth | Potassium: help enzyme action (in photosynthesis and respiration) | Magnesium: to make chlorophyll
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Relate mineral deficiencies to their symptons
Nitrate: poor growth and yellow leaves | Phosphate: poor root growth and discoloured leaves | Potassium: poor flower and root growth and discoloured leaves | Magnesium: yellow leaves
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Describe the effects of temperature, oxygen and water on the rate of decay
Increases rate of decay
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Explain how food preservation methods (canning, cooling, freezing) reduce the rate of decay
Canning: foods are heating to kill bacteria and seal in a can to prevent entry of bacteria | Cooling: slows down bacterial and fungal growth and reproduction | Freezing: kill some bacteria and fungi and slow down their growth and reproduction
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Describe how plants can be grown without soil (hydroponics)
This system uses a regulated recycling flow of aerated water containing minerals.
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Explain the advantages and disadvantages of biological control
Advantages: It can avoid the disadvantages of artificial insecticides and do not need replacing | Disadvantages: It can introduce species that eat other useful species, they can become pest themselves,effect food chains which cause unexpected results
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Explain what it means for an ecosystem to be self supporting
Interdependence in food webs, with energy being transferred from one organism to the other. The exchange of gases in photosynthesis and respiration are an overall balance.
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Describe what zonation is
A gradual change in the distribution of species across a habitat
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Explain how isotopes have increased our understanding of photosysnthesis
The usage of a green alga called Chlorella and isotope of oxygen, O18 in a water molecule, showed that light energy is used to split water, not carbon dioxide.
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Explain the effects of limiting factors on the rate of photosynthesis
Light: Photosynthesis only takes place in daytime. Carbon dioxide and higher temperature is also needed for photosynthesis
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Explain how the rate of diffusion can be increased
Shorter distance for the molecules to travel, a bigger concentration gradient, greater surface area for the molecules to diffuse into or from
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Describe the structure of xylem and phloem
xylem vessels – thick strengthened cellulose cell wall with a hollow lumen (dead cells) | phloem – columns of living cells
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Explain how the cellular leaf structure is adapted to reduce water loss
The guard cell changes the size of the stomotal openings, they also contain chloroplasts so photosynthesis will produce sugars which would increase turgor pressure,
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Describe how mineral elements are used to produce useful plant compounds
Nitrogen produces nitrates, phosphorous produces phosphates, potassium produces potassium compounds and magnesium produces magnesium compounds
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Explain how minerals are taken up by root hairs using active transport
A system of carriers transport selected minerals across the cell membrane. Active transport enables mineralsin low concentrations to enter root hairs containing high concentrations. This uptake against the concentration gradient requires energy.
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Explain why increasing temperature, oxygen and water affect the rate of decay
Temperatures at an optimum between 25-37 degrees C will increase respiration rate but higher temperatures will denature enzymes. Oxygen will mean bacteria will respire for reproduction and growth. Water will increase growth and reproduction.
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Explain how saprophytic fungi use extra cellular digestion
It produces enzymes to digest food outside their cells and then reabsorb the simple soluble substances.
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Explain the advantages and disadvantages of hydroponics
better control of mineral levels and disease • lack of support for plant • requires an addition of fertilisers.
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Explain how intensive food production improves the efficiency of energy transfer
It reduces or removes competing organisms such as pests and weeds. Keeping animals insides sheds means they use less energy to keep warm and move, and more energy on growth or production of eggs for hens.
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Explain how leaves are adapted for photosynthesis
Broad so large surface area; thin so gases can diffuse through easily; contain chlorophyll and other pigments chlorophyll and other pigments to absorb light from different parts of the spectrum; network of vascular bundles for support and transport
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Explain how food preservation methods (drying, adding salts or sugar, adding vinegar) reduce the rate of decay
Drying: Removes water so bacteria cannot feed and grow | Salts & sugars: Kill some bacteria and fungi as high osmotic concentration will remove water from them | Vinegar: Will produce acidic conditions which will kill most bacteria and fungi.
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Other cards in this set

Card 2


Recall the balanced symbol equation for photosynthesis


6CO2 + 6H2O --> C6H12O6 + 6O2

Card 3


Explain why plants carry out respiration at all times


Preview of the front of card 3

Card 4


Name the main parts of a leaf


Preview of the front of card 4

Card 5


Explain how leaf cells are adapted for photosynthesis


Preview of the front of card 5
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