biological molecules overview Flashcards
what are monomers
a small unit from which larger molecules are made
what are polymers
a large number of monomers joined together
give 3 examples of a monomer
monosaccharides
amino acids
nucleotides
what is a condensation reaction
joining two molecules together with the formation of a chemical bond and the elimination of water
what is a hydrolysis reaction
it breaks down chemical bonds between two molecules by using water
what is a monosaccharide
a monomer which makes larger carbohydrate molecules.
give 3 examples of a monosaccharide
glucose
galactose
fructose
what type of bond does the condensation reaction between two monosaccharides form
glycosidic bonds
how are disaccharides formed
a condensation reaction between two monosaccharides
how is maltose formed
condensation reaction between two alpha glucose
what type of bonds does maltose have
1-4 glycosilic
how is sucrose formed
condensation of glucose and fructose
how is lactose formed
condensation of glucose and galactose
what is an isomer
two molecules with the same formula but a different structure
what are polysaccharides
many glucose units joined together by glycosidic bonds in a condensation reaction
what two polysaccharides are formed by the condensation of alpha glucose
glycogen
starch
what polysaccharide is formed by the condensation of beta glucose
cellulose
what is the structure of glycogen
alpha glucose
1-4 & 1-6 glycosidic bonds
highly branched
insoluble in water
what is the function of glycogen
storage in animals
what makes glycogen good at its function
it is highly branched which means there are more reducing ends.
this allows glucose to be released quickly and efficiently so animals can respire aerobically
what is the structure of starch
alpha glucose
1-4 & 1-6 glycosidic bonds
not much branching
coiled and compact
insoluble
what is starches function
storage in plants
what makes starch good at its function
starch is coiled and compact which mean that glucose cannot quickly be released so instead it is stored
(this is because plants do not need to quickly run away )
it is insoluble so it doesn’t affect water potential of a plant
it is large so it cannot diffuse from the cell
what is the structure of cellulose
beta glucose
straight chains
1-4 glycosidic bonds
hydrogen bonds between parallel cellulose bonds
fully permeable in water
what is the function of cellulose
structural - cell walls in plants
what makes cellulose good at its function
lots of hydrogen bonds make it strong and they form microfibrils and fibrils
name and describe the biochemical test for reducing sugars
benedict’s solution
put a sample in a test tube
add benedict’s solution
put it in a water bath for a controlled period of time
brick red is positive
the closer to brick red the more monosaccharides are present
what is the difference between alpha glucose and beta glucose
they have a 180 degree rotation at the C1
explain how the benedict’s solution test shows a positive result
(chemically)
benedict’s reagent becomes reduced (gains electrons) from the reducing centre of glucose. sugar becomes oxidised (looses electrons)
how do you get a positive result in benedict’s solution with a non reducing sugar
boil the sugar with hydrochloric acid to return it to a monomer
the add benedict’s solution
name two lipids groups
triglycerides and phospholipids
how are triglycerides formed
condensation of one glycerol molecule and three fatty acid molecules
what bond is formed during the reaction between a glycerol and fatty acid
ester bond
what about their structure means that unsaturated fatty acids liquid at room temperature
the kink in the chain of molecules where the double carbon bond is means that not as many chains can pack together
what about their structure means that saturated fatty acids are solid at room temperature
chains are in straight lines which means they can be closely packed together
what is the difference between a triglyceride and a phosolipid
phosolipids only have two fatty acids and a phosphate head bonded to the glycerol instead of three
triglycerides repel water - phospholipids attract water
what is the function of a triglyceride
energy source
describe the emulsion test
put a food sample in a test tube
add ethanol
shake it inorder to dissolve any lipids in the sample
add an equal amount of water as ethanol and gently shake
cloudy white liquid means a lipid is present
what is an amino acid
the monomer which proteins are made of
draw an amino acid
r
I
H2N - C - COOH
I
H
what is H2N in an amino acid
the amine group
what is COOH in an amino acid
carboxyl group
what is R in an amino acid
carbon containing side chain ( it is different in every amino acid )
what bond is formed during the condensation reaction of two polypeptides
peptide bonds
how many polypeptides in an functional protein
one or more
what three amino acids repeat in collagen
glycine , promine , alomine
what is the primary structure protein
sequence of amino acids
if this changes than it will effect everything else
what is the secondary structure protein
folding of primary structure into an alpha helix or beta pleated sheet
what bonds form in the secondary protein structure
hydrogen bonds form between hydrogen in the amine group and double oxygen bond in carboxyl group
what bonds form in the primary protein structure
peptide bonds
what is the tertiary structure
folding of secondary sequence into a 3D shape
not all polypeptides have tertiary structure
what bonds happen in the tertiary structure protein
disulfide , ionic, hydrogen
hydrophobic interactions
larger round proteins (enzymes ) make lots of bonds
structural proteins (collagen) dont make any
what is the quaternary structure protein
multiple polypeptides join together
the addition of prosthetic group
not all polypeptides have this
what are the two types of protein
globulas and fibrous
what are globulas proteins
functional
highly specific
irregular
what are fibrous proteins
one error wont change the function
repetitive
strengthening
describe the biurets test
put a sample in a test tube with biurets reagent
if it turns purple then protein is present
blue indicates protein is absent
what is an anabolic reaction
making larger moleclues
what is a catabolic reaction
breaking down of moleclues
what glyosidic bond does sucrose have
1-2
