Biology AS (1)
- Created by: smileyface
- Created on: 26-05-11 17:54
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- starch
- in plant cells
- in the form of grains
- large ammounts of it are present in seeds
- it is chains of alpha glucose
- joined by glycosidec bonds formed by condensation reactions
- it is arranges in helix's and it is unbranched, which make it very compact
- It is a energy storage
- Insoluble and so does not draw water into the cell with it and so does not distrud osmosis
- It is insoluble so does not diffuse out easily
- When it is hydrolysed it forms alpha glucose and is readily transp[orted and ready for use in respiration
- GLYCOGEN
- Animal starch
- Mainly present in the liver and in the muschles
- It is smaller chains which are more highly branched
- Thus, it is more readily hydrolysed
- For my respiration
- CELLULOSE
- major component in cell walls
- provides ridgity
- straight unbranched chains run parallel
- This creates hydrogen bonds forming, overall these hydrogen bond prove to be very stron g
- They are then grouped to form microfibrils
- It is made of beta glucose
- And it inserts an inward pressure to prevent influx of water
- PLANT CELL STRUCTURE
- Lonf thin and numberous
- Large vacuole that puches chloroplasts and cytoplasm to the edge
- Numberous number of chloroplasts
- The pallaside cell's function is to carry out photosynthesis
- Chloroplasts has a ) a double envolope, this is a double plasma membrane selective of what it allows in and out
- The grana , 100 stacks of thylakoids...
- Thylakopids, contain the photosyntheitic pigment - chlorophyll... FIRST STAGE OF PHOTOSYNTHESIS
- Stroma - second stage of photosynthesis .... it has other features present like starch grains
- The chloroplasts are apadpted, the grana in the first stage have a large surface area and so this allows for the attachment of chlorophyll, electron carriers
- The stroma in the second stage
- contains enzymes needed for the secondf stage of photosynthesis
- The choloroplasts contain DNA and ribosomes, to manufacture proteins needed for protein synthesis during photosynthesis
- CELL WALL
- these are microfibrils of cellulose
- they are embedded into the matrix
- Microfibrils add an overall huge amount of strength
- Middle lamella cements adjacent cells
- Cellulose wall adds mechanical strength to prevent the cell bursting under pressure of osmotic entry of water
- It also allows water to pass along it
- Plant cells have cell walls and cell surface membranes
- They have a large number of chloroplasts
- They have a large singular vacuole
- They use starch for storage
- Animals
- only have a cell surface membrane
- No chloroplasts
- small vacuole if any scattered…
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