Zusammenfassung der Ressource
Biological
Molecules
- Water
- Bonding
- Hydrogen Bonding
Anmerkungen:
- Weak electrical attraction between the d+ve hydrogen and the d-ve oxygen on the next molecule.
- Properties
- Ice
- Less Dense than water
Anmerkungen:
- Because hydrogen bonds hold water in a rigid lattice.
- High Specific Heat Capacity
- Body temp
Anmerkungen:
- A lot of energy needed to increase the temperature of water.
- We are largely water so large changes of water in the external environment have relatively small effects on your body temp. (as with all living organisms)
- High Boiling Point
Anmerkungen:
- Sweat
Anmerkungen:
- Humans use this property, when liquid sweat lies on the surface of the skin, sweat absorbs the heat energy from the body as it evaporates. The heat need is called latent heat of evaporation. It is our major cooling mechanism
- Same as plant leaves in hot climate cool down by the evaporation of water on their surface.
- Solvent
- Dissolving
- Metabolic reactions
Anmerkungen:
- Many reactions will only take place in a solution as it is easy for the ions/molecules to react with other ions/molecules
- water can flow so it can carry dissolved substances (eg glucose) from one place to another. This happens in our blood, xylem and phloem and urine.
- Viscocity and Density
Anmerkungen:
- most living organisms, containing a lot of water, have a density which is quite close to that of water. This makes it easy for them to swim as they can slightly change their density by filling or emptying air from parts of their body, to float or sink.
- 1.0 gdm-3
- Cohesion and Surface
Tension
Anmerkungen:
- Surface tension:
On the surface their is only cohesion from molecules below so they are pulled downwards. These pulling forces draw them closer together than other parts of the pond so it is a strong layer.
- Proteins
- Structure
- Amino Acid
- Peptide bond
- Hydrolysis
Anmerkungen:
- Where water is used to break down a substance. E.g. poypeptide + water --> amino acids
- Condensation
Anmerkungen:
- a condensation reaction where water is also produced.
- Polypeptide
Anmerkungen:
- Chain of amino acids with peptide bonds
- Amine-NH2
Acid-COOH
- R Groups
- Primary structure
Anmerkungen:
- The sequence of amino acids
- 20 different amino acids found naturally
- Secondary structure
- Tertiary
- Quaternary
- Carbohydrates
Anmerkungen:
- Monosaccharides
- Benedicts solution
- Add Benedicts soln.
- Heat
- Blue= no reducing
sugar
- Green=some
- Brown= more
- Red=most
- Reducing sugars Cu2+
reduced to Cu+ as
sugar gives electron.
- Glucose
- Alpha
Anmerkungen:
- OH on carbon-1 is undA
- glucose+glucose-->maltose-is only made of a glucose
glucose+galactose-->lactose
(animals)
glucose+fructose-->sucrose (plants)
- Beta
Anmerkungen:
- Properties
- Sweet
- Form crystals
- Soluble
in water
- Polysaccharides
- Starch
- Amylose
- Thousands of
a glucose
joined together
in a chain
- Joined by a
glycosidic 1,4
bonds
- Chains of
molecules coil into
a compact helix
- Amylopectin
- Thousands of a
glucose joined
together
- Joined by a 1,4 and
1,6 a-glycosidic
bonds
- 1,6 bonds
creates branches
- Structure
- Compact- good for
storage
- Iodine test
Anmerkungen:
- Add Iodine soln, if starch is present, soln turns blue. (original colour orange/brown)
- Glycogen
- Thousands of
a glucose
joined together
in a chain
- Both 1,4 and
1,6 (unlike
amylose)
- Branched chains
(shorter than
amylopectin)
- Structure
- Arranged around
glycogenin (protein)
giving it a globular
arrangement
- Food store in animals
- Compact
- Unreactive
- Insoluble, forming
granules in liver and
muscle
Anmerkungen:
- Important cos otherwise would affect conc. gradient as it would dissolve in water and affect osmosis.
- Cellulose
- Made of b glucose
- 1,4 glycosidic bonds
- H bonds link adjacent chains
Anmerkungen:
- 60-70 chains form microfibrils,
the number of h bonds give microfibrils TENSILE STRENGTH.
- Microfibrils held together by H-bonds form CELLULOSE FIBRES
- Layers of fibres running in
dif. directions form CELL
WALLS
- Lipids