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Flashcards by alexinnes99, updated more than 1 year ago
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| Question | Answer |
| what is an Ecosystem? | Where a plant or animal lives, its habitat. such as a garden or rainforest |
| What does a kite diagram show? | It shows the distribution of organisms in an area. A kite diagram is a chart that shows the number of animals or plants against distance along a transect. |
| what does a transect line show? | its shows the zonation in the distribution of organisms. The number of organisms of each species can be observed and recorded at regular intervals along the transect. |
| what is biodiversity? | the range of different plants and animals in the world or in a particular habitat. |
| how do you find the population size (using the capture/recapture method)? | population size = No. in 1st sample x No. in 2nd sample ----------------------------------------------- No. in 2nd sample previously marked |
| using a capture/ recapture method you must assume . . . . | -there are no deaths or reproduces -no movement from the organism in/out of area -the marking do not affect the organisms survival rate -the marks do not rub off |
| balanced symbol equation for photosynthesis | 6C0 + 6H O --> C H O + 6O |
| simple sugars such as glucose (in plants)can be : | -used in respiration, releasing energy -converted in cellulose to make cell walls -converted into proteins for growth and repair -converted into starch, fats oils for storage |
| why is starch used for storage? | Because it is insoluble and does not move away from storage area, and does not affect the water concentration of cells |
| what are the two stages of photosynthesis? | -water is split up by light energy releasing oxygen gas and hydrogen ions -Carbon dioxide combines with hydrogen ions producing glucose and water |
| Jan Baptist van Helmont (1580-1644) | Van Helmont grew a willow tree in a weighed amount of soil. After five years, he discovered that the willow tree weighed about 74 kg more than it did at the start. As the weight of the soil had hardly changed, van Helmont concluded that plant growth cannot only be due to minerals from the soil. |
| Joseph Priestley (1733 - 1804) | Joseph Priestley carried out an experiment that showed that plants produce oxygen. He put a mint plant in a closed container with a burning candle. The candle flame used up the oxygen and went out. After 27 days, Priestley was able to re-light the candle. This showed that plants produce a gas that allows fuels to burn. This gas is oxygen. |
| what can change the rate of photosynthesis? | -amount of carbon dioxide -amount of light -temperature (increasing enzyme activity) |
| Cross section of a Leaf | |
| Adaptations of a leaf | -Transparent epidermis Allows more light to reach the palisade cells -Palisade cell layer at top of the leaf and containing most of the chloroplasts To absorb more light -Spongy layer with air spaces Allows carbon dioxide to diffuse from the stomata to the photosynthesising cells, and to provide a very large internal surface area to volume ratio -thin so gases can diffuse easy -broad to absorb most light possible |
| what pigments do leafs have and why? | chlorophyll a and b, carotene, xanthophyll so that the cells can absorb the maximum amount of light, a wider range of wavelengths of light and more. |
| diffusion | Diffusion occurs when particles spread. They move from a region where they are in high concentration to a region where they are in low concentration. Diffusion happens when the particles are free to move |
| osmosis | Osmosis is the movement of water from a less concentrated solution to a more concentrated solution through a partially permeable membrane. |
| Lysis | bursting an animal cell by osmosis |
| Crenation | shrinking an animal cell by osmosis |
| Turgid | a plant cell fully inflated with water |
| Plasmolysed | a plant cell that has lost water causing the cell membrane to be pulled away from the inside of the cell wall |
| Flaccid | a plant cell that is limp through a reduction of pressure inside the cell |
| phloem | Phloem vessels are involved in translocation. This is the movement of food substances from the stems to growing tissues and storage tissues. On the other hand, phloem consists of columns of living cells. |
| xylem | Xylem vessels are involved in the movement of water through a plant from its roots to its leaves. water is: -Is absorbed from the soil through root hair cells -Is transported through the xylem vessels up the stem to the leaves - (transpiration) Xylem vessels consist of dead cells. They have a thick, strengthened cellulose cell wall with a hollow lumen |
| transpiration | Water on the surface of spongy and palisade cells (inside the leaf) evaporates and then diffuses out of the leaf. |
| how does LIGHT affect transpiration? | In bright light transpiration increases The stomata (openings in the leaf) open wider to allow more carbon dioxide into the leaf for photosynthesis |
| how does TEMPERATURE affect transpiration? | Transpiration is faster in higher temperatures Evaporation and diffusion are faster at higher temperatures |
| how does HUMIDITY affect transpiration? | Transpiration is faster in windy conditions Water vapour is removed quickly by air movement, speeding up diffusion of more water vapour out of the leaf |
| how does WIND affect transpiration? | Transpiration is slower in humid conditions Diffusion of water vapour out of the leaf slows down if the leaf is already surrounded by moist air |
| Nitrates (Nitrogen) | For proteins, which are needed for cell growth Nitrogen is needed to make amino acids for proteins |
| Phosphates (Phosphorus) | For respiration and growth Phosphorus is needed to make DNA and cell membranes |
| Potassium compounds (Potassium) | For respiration and photosynthesis Potassium is needed in enzymes involved in respiration and photosynthesis |
| Magnesium compounds (Magnesium) | For photosynthesis Magnesium is needed to make chlorophyll |
| Nitrate | Poor growth, yellow leaves |
| Phosphate | Poor root growth, discoloured leaves |
| Potassium | Poor growth of fruit and flowers, discoloured leaves |
| Magnesium | Yellow leaves |
| what is active transport? | the root hair cells have carrier molecules on their cell membranes. These pick up the mineral ions and move them across the membrane into the cell against the concentration gradient. Active transport needs energy from respiration to happen. |
| what effects the rate of Decay? | Temperature Amount of oxygen Amount of water The presence of microorganisms |
| what are saprophytes? | bacteria and fungi that cause decay by releasing enzymes onto the dead animal or plant. These break down complex compounds into simple soluble ones that can be absorbed by decomposers. Organisms that feed on dead material in this way are called saprophytes. |
| what are detritivores? | detritivores help speed up decay by feeding on detritus. This is dead and decaying material. They break it down into smaller pieces, so increasing the surface area for the bacteria and fungi. |
| Examples of detritivores? | -Earthworms that help break down dead leaves -Maggots that feed on animal tissue -Woodlice that break down wood |
| how does LOW temperature effect the rate of decay? | Low temperatures slow decay Reduced rates of reaction, and rate of growth and reproduction of decomposers reduced |
| how does HIGH temperature effect the rate of decay? | High temperatures prevent decay Enzymes and proteins denatured, decomposers killed |
| how does the amount of oxygen effect the rate of decay? | Lack of oxygen reduces the rate of decay Oxygen is needed for respiration by decomposers |
| how does the amount of water effect the rate of decay? | Lack of water reduces the rate of decay Water is needed for transport and to support reactions inside decomposers |
| How does canning prevent decay? | The sealed can is heated to kill bacteria. When it cools, no more bacteria can enter. |
| How does cooling prevent decay? | The food is kept at a low temperature (4°C) so bacteria cannot reproduce (they are not killed). |
| How does freezing prevent decay? | Bacteria cannot reproduce at low temperatures and the water in the food is frozen. |
| How does drying prevent decay? | Removing water prevents the microorganisms from growing, or digesting the food. |
| How does adding salt or sugar prevent decaying? | Removes water by osmosis |
| How does adding vinegar prevent decaying? | Reduces the pH to prevent the enzymes in the microorganisms from working. |
| what are the effects of insecticides? | insecticides like DDT don't break down quickly. It's been responsible for a large reduction in bird numbers since intensive farming became widespread. DDT accumulates in food chains - as consumers eat large numbers of prey containing the insecticide. |
| what is intensive farming? | Food production in this field has been increased by growing high-yield crops, removing other plants and pests and adding fertiliser to the soil. |
| what is Biological control? | Biological control is an alternative to using pesticides. By releasing a natural predator into the crop growing area, the number of pests can be reduced. |
| disadvantages of biological control? | This can have unforeseen consequences as the numbers of different organisms in the food web are changed. There have been examples of the predator becoming a more serious pest than the original problem. |
| what is hydroponics farming? | the process of growing plants in sand, gravel, or liquid, with added nutrients but without soil. Due to the costs involved, hydroponics is used only for high-value crops. Monitoring and adjusting the concentrations of minerals in the solution enable the grower to control growth. |
| examples and explanation of organic farming | -Fertiliser. Recycles waste, improves soil structure. Difficult to apply and cannot control mineral content -Crop rotation. Single crop. Reduces disease and damage to soil composition. Less productivity. Less efficient to grow different crops. -Weeding/Herbicides. Less environmental damage, or health risk Labour intensive -Nitrogen-fixing plants Nitrogen fertilisers Cheaper, longer lasting Reduces area available for growing crops if part of a crop rotation |
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