Biological Molecules Flashcards
Monomer Definition
- smaller units from which larger molecules are
made.
Polymer definiton
- molecules made from a large number of monomers
joined together.
3 examples of monomers
Monosaccharides, amino acids, nucleotides
reaction that joins two molecules?
Condensation reaction
a condensation reaction involves
- Formation of a bond
- Elimination of water molecule
reaction that seperates two molecules?
- Hydrolysis
a hydrolysis reaction involves
- Breaking chemical bond
- Uses molecule of water
Monomer of carbohydrates
Monosaccharides
what are the different monosaccharides
- Glucose
- Fructose
- Galactose
monomers of lactose
- glucose
- galactose
monomers of sucrose
- glucose
- fructose
monomers of maltose
- glucose
- glucose
what bond is formed between monosaccharides
glycosidic bond
how is a glycosidic bond formed + what does it consist of
- Condensation reaction
- Formation of chemical bond
- Releases molecule of water
isomers of glucose?
- alpha glucose
- beta glucose
what’s the difference between the two isomers?
H and OH reversed
test for reducing sugars
-add benedicts to sample
heat in water bath
what does a positve test show
red/orange ppt
blue -> green -> yellow -> orange -> red
test for non-reducing sugars
-HCL to sample boil - sodium hydrogencarbonate -benedicts to sample heat in water bath
why is sodium hydrogencarbonate used
to neutralise the HCL
what are polysaccharides
condensation of many glucose units
3 examples of polysaccharides are?
- cellulose
- starch
- glycogen
what isomer of glucose is used for each polysaccharide
cellulose - b glucose
starch - a glucose
glycogen - a glucose
where is glycogen found
in animals
what are the 4 main properties of glycogen
- insoluble
- large
- lots of side branches
- compact
insoluble advantage
doesn’t affect water potential
large advantage
doens’t diffuse out
lots of side branches advantage
more active sites for enzymes to act on
quicker hydrolysis + release of glucose
where is starch found
in plants
two components of starch are?
- amylose
- amylopectin
two key properties of starch
- insoluble
- large
structure of amylopectin
- a glucose
- long branched
what are side branches useful for
more active sites for enzymes to act on
quicker hydrolysis + release of glucose
structure of amylose
- a glucose
- long unbranched
- good for storage
why is amylose good for storage
- coiled
- compact
- so more can be stored in small space
test for starch
- iodine in iodide potassium solution
positive result for starch?
blue/black colour
where is cellulose found
in plants
what is the role of cellulose
structural ( cell walls)
what isomer is cellulose made of
b glucose
structure of cellulose
- straight cellulose chains
- held together by hydrogen bonds
- forming microfibrils
hydrogen bonds in large numbers=
more strength
microfibrils provide
structural strength
which polysaccharides have 1,4 links
cellulose
amylopectin
amylose
glycogen
which polysaccharides have 1,6 links
amylopectin
glycogen
two groups of lipids
phospholipids
triglycerides
structure of triglycerides
3 fatty acids
1 glycerol
bond between 1 fatty acid + glycerol
ester bond
what reaction joins the fatty acids + glycerol
condensation reaction
forms a bond
releases molecule of water per bond
structure of phospholipids
2 fatty acids
glycerol
phosphate molecule
a fatty acid is known as a
hydrocarbon ‘tail’
test for lipids
sample + ethanol
shake
add water
positive result
milky emulsion
the R group of a fatty acid can be
variable
saturated or unsaturated
what does it mean if the R group is unsaturated
has one or more double bond between the carbon-carbon
properties of phospholipid
forms a bilayer
due to hydrophobic head and hydrophilic tail
so is barrier to water-soluble substances in centre
properties of triglyceride
insoluble - doesn’t affect water potential
C-H bonds - store LOTS of energy
roles of lipids (5)
- energy reserve (C-H)
- insulator
- protection
- insoluble in water= reduces water loss/waterproofing
- source of water
what happens if lipids are hydrolysed
produces fatty acids
lowers pH
similarities in phospholipids + triglycerides
- contain glycerol
- contain ester bonds
- contain C, H, O elements
- fatty acids in both = saturated/unsaturated
- both insoluble
differences in phospholipids + triglycerides
- phospholipids= 2 fatty acids, triglycerides= 3
- phospholipids = phosphate molecule
- phospholipids= hydrophilic head, hydrophobic tail
- phospholipids= form bilayers/micelles
monomer of proteins
amino acid
2 amino acids is called
a dipeptide
what bond is between amino acids
peptide bond
what reaction forms a peptide bond
- condensation reaction
- formation of a chemical bond
- releases molecule of water
the R group in an amino acid
variable
allows for 20 different amino acids
test for proteins
sample + sodium hydroxide solution
+ copper II solution
positive result
purple
what is the primary structure
- order of amino acids
- peptide bonds between amino acids
secondary structure
- folding of polypeptide chain
- due to hydrogen bonds
- forms a-helix structure or beta-pleated sheet
tertiary structure
- 3-D folding due to:
- ionic bonds
- disulphide bridges (sulfur + sulfur)
- hydrogen bonds
quaternary structure
2 or more polypeptide chains
e.g collagen, insulin, haemoglobin
what shape are globular proteins
compact
spherical
properties + roles of globular proteins
metabolic roles
water soluble
e.g haemoglobin
what shape are fibrous proteins
long
thin
properties + roles of fibrous proteins
insoluble
composed of many polypeptide chains
structure roles
e.g keratin, collagen
