Topic 1 biological molecules H2O, Carbs & Lipids Flashcards
what do u call a molecule that is partly positive and partly negative
dipole/polar molecule
Nitrate ions formula and use
(NO3-) needed in plants for the formation of amino acids–> proteins–>formation of DNA
phosphate ions formula and use
(PO4 -3) formation of ATP ADP and DNA/RNA
Chloride ions formula and use
(Cl-) nerve impulses+secretory systems
hydrogen carbonate ion formula and use
(HCO3-) Buffer blood preventing it from becoming too acidic
sodium ions formula and use
Na+ nerve impulses
Properties of water
polar solvent
transport medium-other substances can dissolve in it
slow to absorb and release heat-high specific heat capacity
cannot be compressed
cohesive- stick together due to forces between the molecules
adhesive-attracted to different molecules
high surface tension
degree angle between 2 hydrogens in water molecules
104.5
general formula for monosaccharides
(CH2O)n
how many carbon atoms in triose sugars
n=3
how many carbon atoms in pentose sugars+examples
n=5
eg. Ribose, deoxyribose
how many carbon atoms in hexose sugars
n=6
glucose galactose and fructose
Test for reducing sugars
Benedicts solution –>solution of light blue Cu(2) ions when heated with reducing sugars it reduces Cu(2) to Cu(1) ions turning from blue to orange
Test for non-reducing sugars (EG. sucrose)
heat non reducing sugars with a few drops of HCl, allow to cool, add sodium hydrogen carbonate to neutralise glycosidic bonds.
—>monosaccharide forms, you can then use the benedict test
what are molecules with 3-10 sugar units known as
oligosaccharides
what are molecules containing 11 sugar units or more
Polysaccharides
what about the structure of polysaccharides makes them ideal storage molecules within a cell
compact molecules, take up little space
physically and chemically inactive, do not interfere with other functions of cell
not very soluble in water- causes no osmotic water movements
examples of where hydrolysis takes place
digestion in the gut
muscle and liver cells-when carbohydrate stores are broken down to release sugars for use in cellular respiration
starch is a mixture of which 2 compounds
amylose-unbranched polymer- spirals
amylopectin-branched polymer-terminal glucose molecules that can easily be broken off when energy is needed
similarities between amylose and amylopectin
both long chains of alpha glucose molecules
differences between amylose and amylopectin
amylose- 1,4 glycosidic bond-long and unbranched
amylopectin- 1,4 glycosidic bonds but also a few 1,6. therefore it has branching chains
glycogen properties
made of alpha glucose units.
very compact
more 1,6 glycosidic bonds
—> side branches, glycogen can be broken up quickly for energy
describe structure of cellulose
insoluble
its monomers are beta glucose, held together by 1,4 glycosidic bonds.
one monomer unit is inverted, hydroxyl groups stick out.
therefore, hydrogen bonds can form between partially positively charged hydrogen atoms of the hydroxyl groups
cellulose does not coil up, straight long chains.
what are lipids made of
carbon, oxygen and hydrogen
fatty acids and glycerol
what bonds combine the organic chemicals in lipids??
ester bonds
what is the glycerol chemical formula
C3H8O3
How can fatty acids vary
length of carbon chain can differ(usually 15-17)
can be a saturated or a unsaturated hydrocarbon
example of a saturated fatty acid
stearic acid
bonds in a saturated fatty acid
single covalent bond
bonds in a unsaturated fatty acid
one or more double covalent bonds
bonds in a monounsaturated fatty acid
one double bond
bonds in a polyunsaturated fatty acid
2 or more double covalent bonds
example of polyunsaturated fatty acid
linoleic acid
define esterification
the formation of ester bonds
condensation reaction between a carboxylic group(COOH-)of the fatty acid and a hydroxyl group(-OH) of the glycerol
what is a phospholipid
a chemical in which glycerol bonds with 2 fatty acids and an inorganic phosphate group
what do we call molecules that dissolve readily in water
hydrophilic
what do we call molecules that do not dissolve in water
hydrophobic
define monolayer
single closely packed layer of atoms and molecules
hydrophilic head in the water and hydrophobic lipid tails in the air
define a micelle
a spherical aggregate of molecules in water with hydrophobic areas in the middle and hydrophilic areas outside
what is a bilayer
a double layer of closely packed atoms or molecules
phosphate ions formula
PO4 3-
cellulose formula
(C6 H10 O5)n
how to form a triglyceride
esterification between glycerol and 3 fatty acids
Uses of lipids due to their properties
hydrophobic–> waterproofing organisms
fatty sheath insulation for nerves so electrical impulses travel faster
insulate against heat loss
low density- helps mammals float
insoluble in water so lipids do not interfere with the many water based reactions that happen in the cytoplasm of a cell
How is a phospholipid formed
when a hydroxyl group from glycerol undergoes esterification with a phosphate group instead of a fatty acid
describe structure of a phospholipid
Phosphate is polar with a slight negative charge making it hydrophilic
the glycerol is hydrophobic and so are the 2 fatty acid tails therefore they do not dissolve in water.
difference in cis arrangement vs trans arrangement
Cis- hydrogen on the same side
trans-hydrogen on the opposite side
