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Karteikarten von ashley.amber, aktualisiert more than 1 year ago
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| Frage | Antworten |
| why do you get cramps if a 'burst' of physical activity is continued for too long? | anaerobic respiration can only provide enough energy for the muscles to keep going for a short period- a build up of lactic acid can cause cramps |
| what are the 3 main ways molecules and ions can move through a membrane? | diffusion active transport osmosis |
| what is diffusion? | the movement of a substance towards the concentration gradient (e.g if a cell was producing co2 in respiration, the concentration will be higher inside) |
| what is active transport? | the movement of particles against the concentration gradient using energy from respiration |
| what increases the rate of diffusion? | a steep concentration gradient high temperatures large surface area to volume ratio |
| what is osmosis? | the movement of water from a dilute solution to a more concentrated solution (against the concentration gradient) |
| what is the cell wall of a fungus made of? | chitin, not glucose |
| what is a bacteria's cell wall made of? | polysaccharides and protein |
| function of the slime capsule | extra protection for the cell |
| function of the flagella? | to help the bacteria swim |
| function of the plasmids? | contain the bacteria's genes |
| what do bacterium have instead of a nucleus? | a chromosome (loop of DNA) |
| what is a substrate? | a molecule an enzyme acts on |
| what is the small area on an enzyme's surface called? | an active site |
| how does an enzyme lower the energy needed for a reaction? | a substrate molecule enters an active site, which lowers the energy needed for a reaction to take place, allowing products to be formed more easily |
| what 2 factors effect an enzymes ability? | temperature and pH |
| what is the optimum temperature for an enzyme to work at? | 37 degrees C higher temp- enzyme denatures |
| why does a higher temp affect an enzymes ability to work? | a higher temp gives molecules of enzymes and substrates more energy so they collide more often/the reaction is more frequent. |
| what is the optimum pH level for an enzyme? | the inside of a cell is neutral, so they work best at pH7 |
| what happens to an enzyme if the surrounding is on either side of pH7? | the activity decreases, pH effects structure of enzymes and changes the shape of the active site so it doesn't fit as well |
| which enzyme works best at pH2? | pepsin |
| what is respiration? | oxygen is used to oxidise food (glucose), co2 and water is released as waste |
| what two types of energy does glucose release when it is oxidized? | some heat energy, mainly chemical energy |
| what is chemical energy used for? | contraction of muscles active transport building of large protiens cell division |
| what is the word equation for aerobic respiration? | glucose+Oxygen- carbon dioxide+water(+energy) |
| what are the advantages of anerobic respiration? | can occur when oxygen is short in supply (muscle cells) |
| what are the disadvantages of anaerobic respiration? | gluscose isn't completely broken down, less energy released |
| when do muscle cells respire anaerobically? | when they're short of oxygen |
| why do muscles respire anaerobically? | when muscles are overworked, blood can't reach them fast enough to deliver enough oxygen for aerobic respiration. |
| what is the word equation for anaerobic respiration | glucose-lactic acid (+some energy) |
| what are the 7 life processes? | Movement- by muscle action/slow growth Respiration- get energy from food Sensitivity- respond to enviromental changes Growth- increases in size/mass Excretion- remove toxic products Nutrition- find/make food |
| what are the 7 life processes? | Movement- by muscle action/slow growth Respiration- get energy from food Sensitivity- respond to enviromental changes Growth- increases in size/mass Excretion- remove toxic products Nutrition- find/make food |
| features of a plant cell | cell wall membrane vacuole chloroplasts cytoplasm nucleus mitochondria |
| features of an animal cell | nucleus mitochondria cytoplasm membrane |
| function of cytoplasm | site of chemical reactions |
| function of the nucleus | controls activity in cells- contain genetic material |
| function of the membrane | selectively permeable wall of the cell |
| function of the mitochindria | release energy that the cell can use for respiration |
| function of the cell wall | made of celulose, keeps cell's shape. large holes- freely permeable |
| function of the vacuole | filled with cell sap- stores dissolved sugar, mineral ions and other solutes |
| function of the chloroplasts | absorbs light energy for photosynthesis. |
| what controls chemical reactions in cells? | enzymes (biological catalysts) |
| why do we need enzymes? | enzymes speed up reactions- temps inside organisms are low and without enzymes, reactions would be far to slow for life to continue |
| why are there thousands of different enzymes? | because they're made of protien molecules which come in various shapes/structures |
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