Edexcel Additional Science Biology Topic 2- Life Processes


a mind map showing the key points from topic 2 of edexcel's addditional science course
Mind Map by lewis001, updated more than 1 year ago More Less
Created by hchen8nrd about 9 years ago
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Edexcel Additional Science Biology Topic 2- Life Processes
  1. Respiration
    1. The process of breaking down glucose to release energy, which goes on in every living cell
      1. Aerobic Respiration- uses oxygen, it's the most efficient way to release energy from glucose. Muscles need the 02 to respire and gain energy etc.
        1. Glucose + Oxygen -> Carbon Dioxide + Water (+ Energy)
          1. Anaerobic Respiration- happens during quick and intense exercise, when there's not enough oxygen. It doesn't release as much energy and produces a build up of lactic acid which can result in cramps
            1. After anaerobic respiration you have an oxygen debt, the amount of O2 needed to 'repay' is called EPOC. Excess Post-Exercise Oxygen Consumption. Your breathing rate gets higher after you stop to get O2 into your system, additionally your heart rate stays up to get O2 to your muscles. it converts lactic acid into CO2 and H20
              1. Glucose -> Lactic Acid (+ Energy)
                1. Cardiac Output= Heart Rate x Stroke Volume
      2. Waste and Raw Materials
        1. Waste and Raw Materials diffuse in and out of cells. Diffusion is the movement of particles from an area of high concentration to low concentration
          1. The circulatory system carries glucose, O2 and C02 around the body in the blood. Glucose comes from the digestive system; oxygen from breathing and C02 is breathed out. Capillaries supply the glucose and 02 and take away C02
            1. When cells respire, O2 and glucose is used up so the concentration is low. The concentration of the substances in the blood is lower so they diffuse from the capillary into the blood
              1. When cells respire they produce CO2. The concentration of CO2 in cells is higher than in the capillaries so it diffuses out. The bigger the difference in concentration the faster the rate of diffusion.
        2. Photosynthesis
          1. Photosynthesis is the process of making 'food' in plants. The 'food' is glucose. it happens inside chloroplasts. the chlorophyll inside absorbs energy from sunlight and uses it to convert C02 and H20 into O2 and glucose
            1. Carbon Dioxide + Water -> Glucose + Oxygen
              1. Adapt- ations of Leaves
                1. they're broad so they have a large surface area exposed to light
                  1. Contain lots of chloroplasts and chlorophyll to absorb light
                    1. they're thin- decrease the distance C02 has to diffuse
                      1. they've got holes called stomata; they open and close to let gases like C02 and 02 in and out
                        1. Limiting Factors
                          1. Light- Not enough light slows down the rate of photosynthesis. light provides energy for photosynthesis, if you increase the intensity the rate of photosynthesis will also increase to a point. Beyond that it wont make a difference because another factor will be limiting
                            1. C02- the amount available will also affect the rate of photosynthesis because it's a raw material needed. increasing the quantity will increase the rate up to a point but other limiting factors will prevent it from increasing any further
                              1. Temperature- generally if temp is a limiting factor it is because it's too low the enzymes needed for photosynthesis dont work and if its too hot the enzymes will be denatured.
                          2. Structure Of Leaves
                            1. Epidermis is thin and transparent to allow more light to reach the palisade cells
                              1. thin cuticle made of wax to protect the leaf but not block out light
                                1. there's a palisade layer of cells at the top of the leaf containing chloroplasts to absorb light
                      2. Transport in Plants
                        1. OSMOSIS- the movement of water particles through a semi-permeable membrane from an area of high concentration to low concentration
                          1. Takes in water by osmosis. Their long hairs stick out into the soil. The entire branch of a root is covered in millions of these cells; this gives the plant a karge surface area for absorbing water. there's usually a higher concentration of water in the soil than in the roots, so water can enter via osmosis
                            1. Minerals are taken in by active transport. the concentration in the soil is usually lower than in the root hair cell so minerals can get in by diffusion. Active transport uses energy from respiration to help the plant pull minerals into the root against the concentration gradient.
                              1. Plants have tube networks to move substances to and from cells
                                1. XYLEM- transports water and minerals from the roots to the rest of the plant.
                                  1. TRANSPIRATION
                                    1. transpiration is the loss of water in a plant and is caused by the evaporation and diffusion of water in leaves
                                      1. when water is lost, it creates a slight shortage. so more water is pulled up through the xylem vessels to replace it. this is a transpiration stream which is a side effect of the way leaves are adapted to photosynthesis. their stomata allows gases to be exchanged but also allows water to escape.
                                  2. PHLOEM- transports sugars from the leaves to growing and storage tissues
                              2. ROOT HAIR CELLS
                            2. Distribution of Organisms
                              1. Environ- mental Factors
                                1. environmental factors could effect the distribution of organisms
                                  1. Temperature measure using a thermometer or probe
                                    1. Soil pH- use indicator liquid or an electronic pH monitor
                                      1. Light Intensity- use an electronic light sensor
                                  2. METH -ODS
                                    1. POOTERS- jars with a rubber bung. 2 straws stick out of the bung and into the jar; one is longer than the other. the shorter one has mesh covering the opening inside the jar to prevent insects getting sucked into your mouth. the larger tube is used to put over the insect and using the short one suck. So it ends up in the jar
                                      1. PITFALL TRAPS- place a steep sided container into the ground so that the opening is at ground level. put the lid on stones so it's raised but insects can still crawl under. leave over night and see how many insects have fallen in.
                                      2. SWEEP NETS- a net lined with strong cloth for collecting insects, spiders etc from long grass. Stand in your first sample area and sweep the net and turn the insects out into a container and count them.
                                        1. POND NETS- used for collecting insects, water snails etc from ponds and rivers. sweep it along the bottom, turn it out and count.
                                        2. QUADRANTS- a square frame that is divided up and encloses an area. Random areas of the quadrant are chosen and the organisms counted, this is repeated and the results compared
                                          1. for all methods repeat in different sample areas and work out avergaes
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