2.2 biological molecules Flashcards
what is a monomer
a single unit/molecule that binds to other identical monomers to form a polymer
what is a polymer
a large molecule mad up of many monomers joined together
what is a dimer
two monomers joined together
what is a covalent bond and what is it between
sharing electrons with other atoms
two non metals
what is a hydrogen bond
a weak interaction that occurs when two molecules contain a slightly + charged and - charged hydrogen atom
what is a condensation reaction
two molecules joined with the removal of water
what is a hydrolysis reaction
molecule split into two smaller molecules with the addition of water
name the properties of water
liquid
ice is less dense
solvent
strong cohesion and surface tension properties
high specific heat capacity
high latent heat of vapourisation
reactant
describe what is meant by water being a liquid
its constantly moving around and is making and breaking hydrogen bonds
what are the benefits of water being at liquid at room temperature
provides habitats
forms a major component of living tissues
provides a reaction medium
provides a transport medium
describe what happens to water as it reaches about 4 degrees and freezes
as water gets cooler it gets more dense until 4 degrees
the polar nature means the water molecules realign themselves in a less dense structure
the hydrogen bonds hold the molecules further apart
so the layer floats
why is it beneficial that ice is less dense then water
provides an insulating layer and helps keep a stable environment
so aquatic animals can still swim etc.
why is water a solvent and what does it allow
its polar so its attracted to the + and - solutes
allows molecules/ions to be transported (dissolved) and move around and react together
what does cohesion and surface tension mean and allow
hydrogen bonds pull the water molecules closer together
at the surface it allows it to contract and resist force applied
water to be pulled up through a column and insects to walk on it
why does water have a high specific heat capacity and what does it provide
it can absorb a lot of energy and doesn’t heat up or cool down quickly
provides a stable environment to live in and a stable temp for enzymes
what does high latent heat of vapourisation mean and what does it do
a large amount of energy to be absorb to evaporate
keeps temp stable
cools living things
name the inorganic cations
calcium Ca*2+
Sodium Na+
Potassium K+
Hydrogen H+
Ammonium NH4+
name the inorganic anions
nitrate NO3-
Hydrogencarbonate HCO3-
Chloride Cl-
Phosphate PO4 *3-
Hydroxide OH-
what is a deficiency
not consuming enough of a particular ion
what are amino acids and their structure
monomers of all proteins
central carbon
carboxyl group (COOH)
amino group (NH2)
R group
hydrogen
what is a protein and name their functions
large polymers of amino acids
-structural components
-adopt specific shapes
-membranes have protein constitutes that act as carriers/ pores for active transport/f.diffusion
what is the bond formed between amino acids
peptide bonds
what is a dipeptide
two amino acids joined together
what is a polypeptide
a long chain of amino acids joining together
what reactions creates a peptide bond between two amino acids
condensation reaction
produces water a product
(-COOH) from one amino acid becomes (-CO)
(-NH2) from the other aa becomes (-NH) with a peptide bond between them
the OHH makes water (H20)
what reactions breaks the peptide bond between two amino acids
hydrolysis
addition of water and is used up
what is the primary structure of a protein
sequence of amino acid in a protein chain (polypeptide)
why is it important that the order of amino acids doesn’t change in the primary structure
order determines the structure and shape of the protein and therefore the function
what is the secondary structure of an amino acid
chain of amino acid coils into an alpha helix or folds into a beta pleated sheet
what bond is in the secondary structure and what is it between
hydrogen bonds between the amino and carboxyl group of different amino acids
3D
what is the tertiary structure of a protein
overall 3D shape of a protein
coils and pleats begin to fold in with areas of straight chains
what bonds hold the tertiary structure and in what shape
hydrogen, disulfide and ionic bonds between R groups
very precise shape
-globular proteins or fibrous proteins
what is the quaternary structure of a protein
more then one polypeptide chain and a non protein group
what bonds hold a quaternary structure
hydrogen, disulfide and ionic bonds
what do hydrogen bonds form between
form between hydrogen atoms with slight positive charge and other atoms with a slight negative charge
what groups in amino acids do hydrogen bonds form between
amino, carboxyl, hydroxyl groups
what is the role of hydrogen bonds
keeps tertiary and quaternary structure of protein in the correct shape
provides strength
what do ionic bonds form between
carboxyl and amino groups part of the R group
what do ionic bonds do to the groups
ionises them into NH3+ and COO-
strong attraction which forms bond
what do disulfide bonds form between and what type of bond is it
between the R groups of two cysteines containing sulfur
strong covalent bond
what do hydrophobic parts of R groups do
associate in the center of the polypeptide to avoid water
what do hydrophilic parts of R groups do
associate near the edge of the polypeptide to be close to water
what do hydrophobic and hydrophilic interactions cause
twisting of amino acid chain
results in protein changing shape
what are globular proteins
spherically shaped molecules which are soluble in water and have metabolic roles within an organism
how are globular proteins water soluble
has hydrophobic R groups turned inwards
hydrophillic R groups on the outside
so water molecules easily cluster around them and bind to them
what are fibrous proteins
a long, thin structure thats insoluble in water, metabolically inactive but provides structural roles within an organism
name 3 fibrous proteins
collagen
keratin
elastin
name 3 globular proteins
haemoglobin
insulin
pepsin
what is the function of collagen and name some specific examples
provide mechanical strength
-arteries = a layer helps to withstand high pressure
-tendons=connect muscle to bone helps to pull bones
-bones=makes them hard reinforced with calcium phosphate
-cartilage and connective tissue
what is the function of keratin and why is it suited to its role
provides mechanical strength and protection (strong hard body parts)
nails,hair,claws,hooves,horns etc
contains lots of cysteine (amino a.) so lots of strong disulfide bridges
what is the function of elastin and why is it suited to its role
allows stretching/ adaption of shape in living things
cross linking and coiling make it strong and extensible
-skin, lungs, blood vessels
haemoglobin
-structure
-type of protein?
-function/how it works
(quaternary)
made of 4 polypeptide chains (2x alpha globin chains and 2x beta globin chains)
has a haem group / prosthetic group containing iron ion
is a conjugated protein
oxygen binds to each of tthe 4 haem groups
what is the structure of insulin
made of two polypeptide chains
A chain begins with an alpha helix
B chain ends with a beta pleated sheet
tertiary structure joined by disulfide links
how is insulin suited to its role
hydrophillic R groups = outside = soluble in water
insulin binds to glycoprotein receptors
pepsin
-function
-structure
-how is it suited to conditions
digest protein in the stomach
single polypeptide chain, folds into a symmetrical tertiary structure
very few AA with basic R groups, more with acidic R groups , few basic groups to accept H+ ions = stable
what is a prosthetic group
a non protein group that’s permanently attached to a protein
what is a conjugated protein
a protein associated with a non protein group
what do carbohydrates contain
carbon
hydrogen
oxygen
what are the role of carbohydrates
source of energy
store of energy
structural units
what are monosaccharides
simplest carbohydrates
state the properties of monosaccharides
source of energy due to large number of h-C bonds
taste sweet
soluble in water
insoluble in non polar solvents
exists as straight chains/ring/cyclic forms
monomers of complex carbs
what are disaccharides and what are they joined by
two monosaccharides joined together by glycosidic bonds
name properties of disaccharides
sweet
soluble
name 4 examples of disaccharides and what they are made of
alpha glu. + alpha glu. = maltose
beta glu. + fructose = sucrose
beta galactose + alpha glu.= lactose
beta + beta = cellobiose
what reactions forms and breaks glycosidic bonds
condensation reaction
hydrolysis
name a non reducing sugar
sucrose
name reducing sugars
maltose and lactose
what is the structural difference between alpha and beta glucose
the hydroxyl group and hydrogen on carbon 1 are reversed
what is the structural difference between ribose and deoxyribose
ribose has two hydoxyl groups on carbon 2/3
deoxy only has it on carbon 3
what type of sugar are alpha and beta glucose
hexose
what type of sugar is ribose and deoxyribose
pentose
what are polysaccharides
polymers of monosaccharides
what is homopolysaccharide and heteropolysaccharide
homo= same type of monosaccharides
hetero= different types
describe the structure of starch and its function
alpha glucose
in two different structural units
-amylopectin
-amylose
storage of energy in plants
insoluble
describe the structure of amylose
long chain of alpha glucose in coil shape
1-4 glycosidic bonds
hydrogen bonds hold coil
less soluble
describe the structure of amylopectin
long chain of alpha glucose
1-4 glycosidic bonds
1-6 glycosidic bonds = branched
describe the structure of glycogen and function
long chain of alpha glucose
1-4 glycosidic bonds
1-6 glycosidic bonds = branched
compact
act as energy store in animals
insoluble
describe the structure of cellulose
homopolysaccharide of beta glucose
1-4 beta glycosidic bonds
straight chain
(hydroxyl and hydrgoen)reversed so straight chain
insoluble
what is a phospholipid
2 fatty acids and a phosphate head joined to a glycerol backbone
how do phospholipids behave in water
hydrophobic fatty acid tails are non polar and repel water so face inwards
hydrophillic phosphate head is polar and attracts water so faces outwards
what is a bilayer and what does it form
two layers of phospholipids
membranes
what is cholesterol
steroid alcohol/ sterol which is a lipid not made of glycerol or fatty acids
made of 4 carbon based rings
what is the role of cholesterol
provide stability/ regulate fluidity of membrane
what is a triglyceride
A glycerol and 3 fatty acids
What is the structure of a glycerol
3 carbon
Each have one OH
Filled with H
Which is more soluble amylose or amylopectin
Amylose
how to test for proteins
spotting tile
pipette
biuret solution
blue to lilac
how to test for starch
spotting tile
pipette
iodine test
brown/ range to blue/ black
how to test for lipids
test tube
filter paper and funnel
pipette
Emulsion test + Reagents
add ethanol
mix with water
filter and add water to filtrate
clear/colourless to cloudy/ milky
how to test for reducing sugars
benedicts reagant
heat
coloured precipitate should form
high concentration = brick red/brown
how to test for non reducing sugars
add hydrochloric acid and heat
neutralise the solution with sodium hydrogencarbonate
add benedicts and heat
how do you complete a serial dilution
distilled water
stock solution
use same volume to make each solution
explain how colorimetry works
zero/ calibrate with distilled water
use a range of known (glucose)
concentrations
measure percentage transmission
(light) absorption of glucose
solution(s)
by placing samples in cuvette
red filter
how to find RF value
spot/solvent
