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biology... - Coggle Diagram
biology...
topic 1: cell structure
enzymes
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they have a substrate and an active site, in which thre substrate binds to the active site in a theory called the 'lock and key theory' meaning every enzyme has a specific substrate that fits...
the active site can denature.. this means it changes shape and the substrate that matches no longer fits.. this slows down the reaction as there are fewer successful collisions between the substrate and active site. denaturation can be affected by...
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cell types:
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prokaryote
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prokaryotes have different cellular structures to eukaryotic cells, for example prokayotes do not have a nucleus, and instead have a single DNA loop (chromosomal DNA) in their cytoplasm..
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transport
diffusion factors effecting: temperature=rate of diffusion -- membrane surface area: the larger the surface area the faster the rate-- concentration gradient: difference in concentration between to areas.. the bigger the difference the greater the gradient and the faster the rate.
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osmosis partially permeable membrane allows water through, but wont let large molecules dissolved in water through. water movement.. water will move to make the concentration the same on both sides by diluting it.. net movement of water: water molecules move through the membrane in both directions but the NET movement of water ( overall movement ) will be from dilute to concentrated. high conc of water --> low conc of water
an experiment to test this is cutting disks of potato, weigh the potatoes and then put in a solution of sugar or salt. after 30 mins weigh thr potatoes again and then work out the % change in mass
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active transport allows sugar molecules, which are needed for cell respiration, to be absorbed by the blood from the gut, even when sugar conc in blood is higher. mineral absorption in plants, which is necessary for growth. even though the conc of minerals is usually lower in the soil than in the root hair.
LOW --> HIGH energy is required for active transport! PROVIDED BY RESPIRATION, energy is required as it move AGAINST its conc gradient.
genetics
meiosis
meiosis is the result of four genetically NON identical cells. similar to MITOSIS which is the production of TWO diploid daughter cells
so how does this happen?? each cell comes with a set of chromosomes, during meisosi the set of chromosomes replicate and split in two
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topic 6.. P2 plants
photosynthesis.. what exactly is it?? well, photosynthesis is the plants own way of producing its own food, this occurs in the chloroplasts of the plant cells (these are what gives the leaves their green colours)
this is an endothermic reaction, meaning it takes IN head energy from its surroundings in order to photosynthesise. the source of this heat energy is sunlight, which si then trapped in chlorophyll inside the chloroplasts, and used to make carbohydrates
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but how do we increase the rate?? increasing the CO2 concentration, increases the rate of photosynthesis- however above a certain threshold, further increase in the concentration doesnt actually effect the rate, as another factor such as sunlight intensity is limiting the reaction, this is a limiting factor... :((
TEST FOR LIGHT INTENSITY: we can test this using pond weed and a lamp! using a ruler change the dustance of the lamp and the pondweed. the weed being in glass jars filled with water and sealed. count the number of bubbles produced per minute and record this. the bubbles are oxygen and shows the rate of photosynthesis!
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