biological molecules Flashcards
what is a monomer?
smaller units that form larger molecules
what is a polymer
molecules made from large numbers of monomers joined together
what are examples of monomers?
-monosaccharide
-amino acids
-nucleotides
what are examples of polymers
-starch
-DNA
-proteins
what is a condensation reaction
the formation of a chemical bond between two molecules.
-eliminating water in the process.
what is a hydrolysis reaction
breaks a chemical bond between two molecules.
-involving the use of a water molecule.
what is the monomer of a carbohydrate
monosaccharide. (one sugar)
what are examples of monosaccharides
-glucose
-galactose
-fructose
what bond is formed during a condensation reaction in monosaccharides
glycosidic bonds
what two monosachharides form the disaccharide MALTOSE
glucose + glucose
what two monosaccharide form the disaccharide SUCROSE.
gluctose+fructose
what two monosaccharides form the disaccharide LACTOSE
glucose+galactose
how are polysaccharides formed?
condensation of many glucose molecules.
what is the structure of glycogen
(animal starch)
- highly branched than amylopectin. with a greater alpha 1-4 and 1-6 glycosidic bonds
what monomer does glycogen have
alpha glucose
what bonds are formed in glycogen
alpha 1-4 and 1-6 glycosidic bonds.
why is glycogen highly branched.
(linking structure to function)
-larger surface area for enzymes to hydrolyse glycosidic bonds.
-glucose—-> aerobic respiration in mammals
why is glycogen insoluble
(linking structure to function)
it wont affect the water potential when in water
why is glycogen compact
(linking structure t function)
more can be stored in a smaller space.
what is glycogen
key energy store in mammals`
what is starch
storage molecule found in plants
what monomer forms starch
alpha glucose molecule
what is the structure of amylose
-unbranched
-coiled helic structure
what bonds occur in amylose
alpha 1-4
why does amylose have a coiled helic structure.
(linking structue to function)
allows cells to store greater amounts of amylose.—> higher energy density.
what is the structure of amylopec tin
highly branched
what bonds form in amylopectin
alpha 1-4 and 1-6 bonds.
why is amylopectin branched.
increase surface area
in order to hydrolyse glycosidic bonds.
where is cellulose found
plant cell walls
what monomers are present in cellulose
beta glucose monmers
what bond is formed in cellulose
beta 1-4 glycosidic bond
why is cellulose comprimiseed of straight chains
beta glucose is invertedd which forms an alternating patterning.
what are stacks of cellulose called
microfibrils
what bond is found within these stacks
hydrogen bonds
how does the structure of cellulose link with its functons
the microfibrils formed= high tensile strength
which is essential with the cell wall of a plant cell that needs to be rigid.
TRUE OR FALSE: all monosachharides are reducing ugars
TRUE
TRUE OR FALSE: all disaccharides are reducing sugars
FALSE
what happens to the benedicts reagent when a reducing sugar is placed in it.
copper oxide forms (insoluble in water)
-and therefore a percipitate as a result .
what is the method to find a reducing sugar?
- add 2cm3 of the food solution to 2cm3 of benedicts then HEAT GENTLY. 5 minutes.
what is a positive result for a reducing sugar.
it goes from blue to red.
the deeper the red, the greater the amount of percipitate formed.
how do we know we can do the practical for a non reducing sugar.
there will be a negative result for benedicts.
blue–>blue
why is dilute hydrochloric acid added to the solution and heated.
to break glycosidic bonds. from disaccharide—> monosaccharide.
what do we do after we add the hydrochloric acid.
-add sodium hydrogencarbonate
why do we add sodium hydrogencarbonate
to neutralise the solution. to make slightly alkaline.
what do we do after we add the sodium hydrogencarbonate
perform the reducing suagrs test as normal.
what are the two groups of lipids.
triglycerides
phospholipids.
how are triglycerides are formed.
condensation
what molecules are formed with a triglycerides?
1 molecule of glycerol
three molecule of fatty acids.
what bond is formed between glycerol and a fatty acid.
ester bond.
(RCOOH)
what can the r group of a fatty acid be?
saturated
unsaturated
what is a saturated fatty acid
it contains single carbon bonds in the hydrocarbon chain
what is an unsaturated fatty acid
it contains a double carbon bond in the hydrocarbon tail.
what molecules make up a phospholipid.
a glycerol molecule
-2 fatty acid chains
-and a phosphate head
how is a phospholipid different to a triglyceride.
one of the fatty acids is substitiuted for a phosphate group.
and there is a covalent bond between the phosphate group.
what is the property of the tail in phospholipid
it is hydrophobic.
it repels water
what is the property of the head in the phospholipid.
it is hydrophilic
attracts water.
how is the tail suited for its properties
-supports the permeability within the membrane
what is the test for lipids
-add ethanol to the food sample
-shake
-place in water
what is a positive test for lipids
it turns a milky emulsion
what monomer forms proteins.
amino acids
how many amino acids are there?
20
what bond forms during a condensation reaction between two amino acids.
peptide bond
how are dipeptides formed
condensation between two amino acids.
how are polypeptides formed
condensation reaction between many amino acids.
how is the carboxyl group presented as?
COOH
what is the amine group presented as?
NH2
what is the primary structure of proteins?
- a sequence of amino acids.
- in a polypeptide chain
what is the secondary structure of proteins?
-formation of alpha helix shapes
-beta pleated sheets.
-hydrogen bonding in the O-H of carboxyl group
-H in amine group
what is the tertiary structure of a protein?
-further folding of secondary structure.
-3D shape
-held together by intermolecular bonds.
what are the three intermolecular bonds found in the tertiary structure
-ionic bonding
-hydrogen bonding
-disulphide bridges.
where are the intermolecular bonds normally found within a protein
R-group.
whats the quaternary structure of a protein?
-protein made up of MANY polypeptide chains.
what is an example of something with many polypeptide chains?
haemoglobin
what happens to the structure of a denatured protein?
-bonds in the tertiary structure are broken
-and the 3D shape is lost.
what is an enzyme?
biological catalysts that speed up the rate of reaction without being used up
how does an enzyme lower its activation energy?
-lowering tthe activation energy.
what is a competitive inhibitor?
-the inhibitor molecule binds onto the active site as its a similar shape.
-the enzyme makes a conformational change.
What is the site that the non-competitive inhibitor binds onto
allosteric site.
what is the role of a non-competitive inhibitor?
-the inhibitor binds onto the allosteric site.
-this changes the active site
-the substrate molecule is no longer complimentary to the active site.
-no enzyme substrate complexes are formed.
what is glycogen
a glucose storage molecule fot humans
what does benedicts solution contain
copper sulfate
CuSO4
what is formed in the pesence of a reducing sugar
copper oxide
insoluble in water
what happens when copper oxide is insoluble in water
forms a percipitate
what does a brick red solution show
high concentartion of reducing sugar
how can we identify an unsaturated fatty acid
a double bond between the carbon atoms
in the hydrocarbon chain
how can ew teest for thee presence of lipids
dissolve in ethanol
add distilled water
shake
milky white emulsion
