Module 2 Biological Molecules Flashcards
Glycosidic bond
A bond formed between two monosaccharides by a condensation reaction
define macromolecule
a molecule containing a large number of atoms
how are polymers formed from monomers
condensation reaction
how is water formed from condensation reactions
the grouping of a hydroxyl (OH) from one monomer and hydrogen (H) from another
how are polymers broken down into monomers
hydrolysis reaction
the general formula of a monosaccharide
(CH2O)n
properties of glucose make it well adapted to its function
- small so easily transported in and out of cells through carrier proteins
- soluble so easily transported around an organism
- less reactive than other monosaccharides so breakdown must be catalysed and therefore controlled by enzymes
list monosaccharides
fructose, galactose, glucose
what is ATP
(adenine triphosphate) an adenine base bonded to ribose and three phosphate groups.
what are the two polysaccarides of starch
amylose and amylopectin
amylose
spiral shape(makes it more compact), long chain of alpha glucose molecules , joined together by 1-4 glyosidic bonds, only has two accessible ends where amylase can bind so it is broken down slowly.
amylopectin
spiral shape,
branched,
joined with 1-4 glycosidic bonds however has the occasional 1-6 glycosidic bond this causes branches,
more accessible ends foe amylase to bond to.
glycogen (in animals)
joined by 1-4 and 1-6 glycosidic bonds (similar to amylopectin),
branching is more often than in amylopectin therefore there are even more accessible ends(can be rapidly hydrolysed to alpha glucose)
cellulose
polysaccharide of beta glucose molecules joined together by 1,4 glycosidic bonds
why are the cellulose chains straight
to be able to form the 1,4 glycosidic bonds each beta glucose molecule must be inverted from the previous molecule because to OHs need to face each other
how do cellulose chains form layers
the chains line up parallel to each other and hydrogen bonds form between hydroxyl groups that are in close proximity to each other on adjacent chains.
how are fibers of cellulose formed
- cellulose chains come together to form micro fibrils
- micro fibrils are then bundled together to form macro fibrils
- the macro fibrils wrap around the plant cells in multiple layers at different angles
what is the role of triglycerides
they are a source of energy found in foods (fats, oils)
what is an ester bond
the covalent bond formed by a condensation reaction between the -OH group of a carboxyl acid and the -OH group of an alcohol
why are fats solid and oils liquid
due to the presence of double bonds between carbon atoms in the fatty acid tail. in unsaturated fatty acids the fatty acids are bent so they are less compact and the space between the molecules increase causing the intermolecular forces to weaken and the molecule becomes a liquid at room temperature.
define saturated hydrocarbon chain
no double bonds (lipids are solid at room temperature)
why do triglycerides release lots of energy
there is a large number of carbon hydrogen bonds that are broken down
what is the biuret test used for
testing proteins (by detecting peptide bonds)
procedure of biuret test
place sample in a clean test tube
add biuret A (sodium hydroxide)
add biuret B (copper (II) sulphate)
if protein is present colour changes from blue to purple
