The Variety of Life - Chapter 10 AQA AS Biology
Chapter 10 AS AQA Biology - unit 2
- Created by: H.N
- Created on: 30-11-12 20:40
View mindmap
- The Variety of Life
- starch
- role
- energy storage
- insoluble - doesn't draw H20 into cell by osmosis
- unbranched chain wound into a tight coil - very compact - a lot packed into small space
- when hydrolysed forms alpha-glucose - easily transported + readily used in respiration
- found in plants but never found in animal cells
- structure
- role
- Glycogen
- structure
- similar to starch - but shorter chains + highly branched
- small granules - mainly in the liver and muscles
- compact
- role
- shorter chains - more readily hydrolysed to alpha-glucose
- important for energy release in animals
- good for storage
- shorter chains - more readily hydrolysed to alpha-glucose
- structure
- Heamoglobin
- structure
- Primary - 4 polypeptide chains
- secondary - chains coiled into helix
- tertiary - chain folded into a precise shape
- quaternary - polypeptides linked to form a spherical molecule
- heam group - Fe2+ ion - can combine with a single 02
- i.e. a single heamoglobin molecule can carry 4 02 molecules
- heam group - Fe2+ ion - can combine with a single 02
- large protein with a quarternary structure
- role
- to transport oxygen
- readily associate with 02 at gas exchange surface
- readily dissociates from 02 at tissues
- changes its affinity in different conditions
- (low p02) presence of C02 - heam molecule binds more loosely to 02 = RELEASES 02
- releases 02 = unloading/Dissociating
- (high p02) Presence of 02 - binds more closely to 02 = O2 ATTACHES TO IT
- combines with 02 = Loading/Associating
- (low p02) presence of C02 - heam molecule binds more loosely to 02 = RELEASES 02
- high affinity for 02 - take up more easily, releases less easily
- low affinity for 02 - takes up less easily, releases it more readily
- to transport oxygen
- oxygen dissociation curves
- further to LEFT= greater affinity for 02 (organisms in low 02 environments)
- further to RIGHT = lower affinity for 02 (organisms that are v. active - high 02 demand)
- greater the C02 conc = more easily hemoglobin releases 02
- dissociation curve shifts down - Bohr effect
- saturation of blood lower at given p02
- dissociation curve shifts down - Bohr effect
- Gas exchange surface - C02 constantly removed=pH raised, higher affinity for 02
- 02 is LOADED
- In the tissues - C02 produced by respiring cells = pH of blood (in tissues) lowered, lower affinity for 02
- 02 is UNLOADED
- structure
- Cellulose
- structure
- made of monomers of beta- glucose
- each beta glucose rotated 180 degrees
- straight, unbranched chains that run parallel to one another
- H bonds form cross-linkages between adjacent chains - adds strength
- molecules group together = microfibrils = fibres
- role
- provides rigidity to the cell wall
- maintain a turgid state to provide maximum surface area for photosynthesis
- structure
- plant cell structure
- leaf palisade cell
- function - carry out photosynthesis
- many chloroplasts - arranged to get max. light
- large vacuole - pushes cytoplasm/chloroplasts to edge of cell
- Chloroplasts
- disc-shaped
- main features
- the chloroplast envelope
- double membrane - surrounds organelles + controls entry/exit of materials
- the grana
- stacks of thylakoids - containing chlorophyll
- 1st stage of photosynthesis occurs here
- stacks of thylakoids - containing chlorophyll
- the stroma
- fluid-filled matrix
- 2nd stage of photosynthesis occurs here
- possesses all enzymes needed for this
- fluid-filled matrix
- the chloroplast envelope
- contain DNA + ribosomes - manufacture proteins for photosynthesis
- cell wall
- no. of polysaccharides
- thin layer (middle lamella) - marks boundary between adjacent cell walls
- functions
- provide mechanical strength - cell doesn't burst
- allow water to move along it
- differences between animal + plant cells
- animal- no cell wall (only cell-surface membrane)
- Chloroplasts in plants not animals
- Vacuole present in plants - rarely animals
- plants - starch grain for storage / animals- glycogen granules for storage
- leaf palisade cell
- starch
Similar Biology resources:
Teacher recommended
Comments
No comments have yet been made