biological molecules Flashcards
What is a monomer
smaller units which can create larger molecules
what is a polymer
molecules made from a large number of repeated monomers joined together
what is a saccharide
sugar
3 examples of monomers
nucleotide, amino acid and monosaccharides
3 examples of polymers
dna, protein and starch
what is condensation
a reaction that joins two molecules together with a chemical bond involving the elimination of a molecule of water
what is hydrolysis
a reaction that breaks down a chemical bond between two molecules and involves the use of water molecules
how are biological polymers formed
from their monomers by condensation
how are biological monomers formed
broken down from their polymers by hydrolysis
what is a unit of carbohydrates called
saccharides
what is a monosaccharide
monomers from which larger
carbohydrates are made
what group is sugar a part of
carbohydrates (containing C, H, O)
3 examples of monosaccharides
glucose, fructose and galactose
3 examples of disaccharides
sucrose, maltose and lactose
3 examples of polysaccharides
starch, cellulose and glycogen
how is a glycosidic bond formed
a condensation reaction between two monosaccharides
how are disaccharides formed
condensation of two monosaccharides
formula for alpha glucose
C6H12O6
draw alpha glucose
search on google
draw beta glucose
search on google
what is an isomer
same molecular formula, different structure
what are the two isomers for glucose
a- glucose and b-glucose
what is the disaccharide maltose formed by
a- glucose + a- glucose
what is the disaccharide sucrose formed by
glucose + fructose
what is the disaccharide lactose formed by
glucose + galactose
how are polysaccharides formed
condensation reaction between many glucose monomers
notes on glycogen
found in animals, made from a- glucose, highly branched and store of glucose
notes on starch
found in plants, made from a- glucose, highly branched and store of glucose
notes on cellulose
found in plants, made form b- glucose, parallel long single chains, hydrogen bond cross linkages, used for cell wall strength
what bond do carbohydrates form
glycosidic
what bond do proteins form
peptide
what bond do lipids form
ester
what bond do nucleic acids form
phosphodiester
what makes a sugar ‘reducing’
can donate electrons
what makes a sugar ‘non reducing’
gains electrons (cannot donates electrons, therefore cannot be oxidised)
how do you find out the chemical formula of a disaccharide
add all the carbons, hydrogens and
oxygens in both monomers then subtract 2 H and 1 O (for the water molecule lost)
why does the liver and muscle cells have a high number of glycogen
higher cellular respiration rate in these cells
bond between glycogen monomers
1-4 and 1-6 glycosidic bonds
properties of glycogen
helical shape
highly branched
made up of lots of glucose
large molecules
how does glycogen’s helical shape adapt it for it’s function
compact so lots of energy can be stored in small areas
how does glycogen being highly branched adapt it for it’s function
increases surface area for enzymes to act on making hydrolysis faster
how does glycogen being made up of lots of glucose adapt it for it’s function
glucose molecules can be obtained through hydrolysis and can be used in respiration
how does glycogen being made of large molecules help adapt it for its functions
its insoluable & unable to leave cell freely, this means they won’t be lost from the cell & also won’t effect water potential
is starch less dense and more soluble than glycogen, what does it mean
glycogen is less dense, more soluble, broken down rapidly, indicating higher metabolic requirements of animals compared with plants
bond between starch monomers
1-4 glycosidic bond in amylose, 1-4 and 1-6 in amylopectin
properties of starch
helical shape
can be branched or unbranched
insoluble
made of lots of glucose
large molecues
how does starch’s helical shape adapt it for its function
compact, lots of glucose can be stored in a small space
how does starch being insoluble adapt it for its function
doesn’t affect water potential, so water isn’t drawn in by osmosis, also can’t leave cell
how does starch being made of lots of glucose adapt it for its function
glucose molecules can be obtained through hydrolysis and can be used in respiration
how does starch having large molecules adapt it for its function
insoluble, and unable to leave the cell freely, can’t be lost from cell
properties of cellulose
straight chains and microfibrils
how does cellulose having straight chains adapt it for its function
chains are close together allowing hydrogen bonds to form between the -OH groups resulting in collective strength
how does cellulose having microfibrils adapt for its function
chains of cellulose are grouped into microfibrils and fibres for more strength
how do cellulose molecules have to be arranged in order to join eachother
alternate molecules need to be inverted due to beta glucose having opposite hydroxyl groups
what bond is found between chains in cellulose
hydrogen
how to test for starch
add food sample in test tube with iodine, if present it goes from orange/yellow to blue black
how to test for a reducing sugar
equal volumes of food sample and benedicts reagent and heat, if a reducing sugar is present it will go from blue to orange/red (it can go from blue, green, yellow, orange or red depending on how much is present)
how to test for non reducing sugars
do benedicts test, if no colour change, get new sample of non reducing sugar, add HCL then heat, then neutralise with alkali sodium hydrogencarbonate, repeat benedicts when neutral, if present will turn red/brown
what function do lipids serve
storage of energy
why are lipids insoluble in water
b/c they’re non polar so don’t attract water molecules but dissolve in alcohol
what is a polar molecule
slight positive at one end, slight negative at the other end
draw glycerol
.
H
|
H - C - OH
|
H - C - OH
|
H - C - OH
|
H
draw a fatty acid
.
O
||
HO - C - R
what are triglycerides
condensation w/ 1 glycerol molecule and 3 fatty acids
3 water molecules eliminted in the process
fatty acids have general formula RCOOH
ester bonds between fatty acid & glycerol
what is esterfication
the forming of an ester bond, between O&C
draw the ester bond in triglycerides
O
||
O - C
what is a saturated fatty acid
all carbon atoms are joined by single bonds
what is an unsaturated acid
atleast one double bond between carbon atoms
what does hydrophilic mean
interacts with water
what are phospholipids made of
glycerol, 2 fatty acid chains, phosphate (the head is hydrophilic while the tail is hydrophobic)
what’s are the properties of triglycerides
lots of carbon hydrogen bonds
low mass to energy ratio
large non polar molecules
high ratio of hydrogen to oxygen atoms
explain why triglycerides have lots of carbon hydrogen bonds
these bonds have high ratio of energy storing bonds so lots of energy is released when broken down
why do triglycerides have low mass to energy ratio
lots of energy can be stored in a small molecule
why are triglycerides large non polar molecules
so they’re insoluble in water & does not affect water potential of cells
also can’t escape cell
explain why triglycerides have a high ratio of hydrogen oxygen atoms
release water when oxidised so provides water
how is the structure of phospholipids related to it’s properties
polar molecules
in aqueous environment they form bilayer –> water soluble substances can’t easily pass membrane
hydrophilic heads attracted to water inside & outside of cell so point outwards
hydrophobic tails point away from water
how do you test for lipids
add ethanol and water to food sample
then shake
if lipid is present it will turn cloudy white emulsion
how does an unsaturated fatty acid affect its hydrocarbon tail
it makes it kink (bend slightly) they can’t pack together tightly
so they’re not as straight as saturated fatty acids
why are lipids not considered polymers
they are formed from fatty acids and a glycerol molecule not repeating units of a single monomer
draw an amino acid
.
R
|
H(little 2)N – C – COOH
|
H
what varies the 20 different amino acids
the R chain
when do peptides form
when the carboxyl group on one amino acid reacts w/ the amine group on another
this forms peptide & water due to condensation
how do amino acids form peptides
carboxyl group reacts w/ amine group
one free amine group at one end and a free carboxyl at the other
how do you test for proteins
equal volume of food sample & biuret solution
shake gently
if protein present, goes from blue to lilac
what is the primary structure of proteins
sequence of amino acids that are joined w/ a peptide bond
sequence determines overall shape of protein
if the sequence is different, overall shape and function is change
what is the secondary structure of proteins
a - helix or b - pleated sheet can be formed
hydrogen bonds between amino group and carboxyl group of two different amino acids
what is the tertiary structure of proteins
3d arrangement
formed by disulfide bridges, ionic and hydrogen bonds
this allows it to be recognised by other molecules
what is the quaternary structure of proteins
contains more than one polypeptide chain
formed by interaction between different polypeptides & is held together by disulfide bonds
description of hydrogen bond in proteins
form secondary structure
between NH groups of one amino acid & C=O group of other
lots in a protein but easily broken
description of disulfide bridge in proteins
bond different polypeptide chains together forming quaternary structure
very strong, not easily broken
description of ionic bond in proteins
formed between carboxyl & amino groups that aren’t involved in forming peptide bonds
weaker than disulfide bonds
easily broken by change in ph
description of peptide bond in proteins
bond between amino acids in a chain formed by condensation reaction, when amine group reacts w/ carboxyl group
water is eliminated during reaction
what is formed when enzymes and substrates bind together
enzyme substrate complex, which turns into an enzyme product complex
how does the induced fit model work
when a substrate binds to active site, the active site changes shape slightly
why can different catalysts be used for the same reaction
shape of active site is the same or different active sites that attach to different parts of a substrate
what is it called when the active site has the same shape as the substrate
the active site is complimentary to the substrate
what is the effect of ph on enzymes if too high or low
the ionic bonds holding the
enzymes, tertiary structure
together break
draw a peptide bond
.
O
||
C – N
|
H
what is an inhibitor
substance that slows down the activity of an
enzyme
some are reversible others are non-reversible.
how do competitive inhibitors work
has a similar shape to substrate
this means it can fit into the active site of an enzyme
prevents substrate from binding to active site
so enzyme-substrate complexes are unable to form
how do non competitive inhibitors work
non-competitive inhibitor binds to a different part of the enzyme and changes its shape
substrate can’t bind
non competitive inhibitors never allow enzyme substrate complex to do what
reach it’s max
what bond does reversible inhibitation form with enzymes
weak hydrogen bonds
what bond does non reversible inhibitation form with enzymes
strong covalent bonds
what site do non competitive inhibitors bind to
allosteric site
what is dna
polymer
deoxyribonucleic acid
holds genetic information
what is rna
polymer
ribonucleic acid
transfers genetic information from DNA to the ribosomes
what is the structure of a nucleotide
phosphate (circle), pentose (pentagon), nitogen containing organic base (rectangle)
what are ribosomes formed by
rna and protein
what sugar does dna contain
deoxyribose
what sugar does rna contain
ribose
what are dna’s bases
adenine & thymine
guanine & cytosine
what are rna’s bases
adenine & uracil
guanine & cytosine
what element do all bases in dna and rna contain
nitrogen
what sugar do dna & rna both contain
pentose
how is a phosphodiester bond formed between two nucleotides
condensation reaction, between phosphate and deoxyribose
what is the structure of dna
sugar phosphate backbone
long
helical shape
specific sequence of bases
double helix
hydrogen bonds at bases
how does the sugar phosphate backbone support dna’s function
provides strength and stability
how does being long and having a helical shape support dna’s function
compact
stores lot of info in a small space
how does having specific sequence of bases support dna’s function
allows info to be stored
how does having a double helix support dna’s function
strands can act as templates
how does hydrogen bonds between bases support dna’s function
double strands can be easily separaed for replication
what are pyrimidines
smaller bases containing single carbon ring structures
example of pyrimidines
thymine, uracil, cytosine
what are purines
larger bases containing double carbon ring structures
examples of purines
adenine, guanine
how to calculate percentage of bases in dna
complimentary bases have same %
subtract their total from 100
divide this by 2
this is percentage for other 2 bases
differences between dna and rna
dna:
long, double strand helix, thymine
rna:
short single chain, uracil
what bond is between complimentary dna bases
hydrogen
what carbons are the phosphodiester bonds between
3rd carbon and 5th carbon
what is the process of dna replication/ semi conservative replication
enzyme dna helicase unwinds double helix, breaks down hydrogen bonds
both strands act as templates
nucleotides line up in complimentary pairs
dna polymerase joins nucleotides together forming phosphodiester bonds
hydrogen bonds between bases reform
each new dna molecule has one original strand and one new strand
what is semi conservative replication and what does it ensure
one strand from template molecule
one strand newly synthesised
ensures new dna is accurate and there is genetic continuity between generations of cells
what direction can polymerase add bases from
5’ (5 prime end) to 3’ (3 prime end)
what is the name of the fragment that polymerase makes on the lagging strand
okazaki fragment
what is the role of dna helicase
breaks weak hydrogen bonds and unwinds dna
what is the role of dna polymerase
catalyses the condensation reaction inwhich nucleotides bond together forming phosphodiester bonds
what scientists supported the semi conservative dna replication
watson and crick
what experiment proved semi conservative replication
scientists grew bacteria in N15 (dense isotope)
bases contain nitrogen so it becomes incorporated in dna
dna strand is dense and towards bottom
then it’s moved to N14 (less dense isotope)
dna copies, 1 strand is N14, other is N15
due to being a mix its in the middle of tube
bacteria divides again in N14
so N14&15 dna stays in middle but N14 dna is near the top in same test tube
draw out the semi conservative dna experiment
test tube 1: gen 0 N15 dna near bottom
test tube 2: gen 1 N15&14 dna in middle
test tube 3: gen 2 N15&14 dna in middle, N14 dna at top
what is atp
nucleotide derivative
adenosine triphosphate
provides an immediate energy source for cells
what is atp formed with
adenine, ribose and 3 phosphate groups
draw atp
phosphate (3 circles), ribose (pentagon), adenine (rectangle)
what happens when atp is broken down
broken down by hydrolysis
into adp and a phosphate group
catalysed by enzyme atp hydrolase
atp being broken down, word equation
atp + h2o –> adp + Pi + energy
what does Pi mean
inorganic phosphate
when is atp resynthesised
during photosynthesis and respiration
how is atp resynthesised
condensation reaction catalysed by atp synthase
adp and phosphate group join to form atp and water
atp resynthesised word equation
adp + Pi –> atp + h2o
what are the products of hydrolysis of atp used for
Pi made in this reaction can phosphorylate other compounds
this makes compounds more reactive
energy is released
this can be used for essential processes in the organism
why is atp useful as an immediate energy source
releases smal manageable amounts of energy so little is lost as heat
energy released instantaneously
can be rapidly synthesised
unable to leave cells
why do organisms need to make lots of atp
b/c can’t be stored, only lasts a couple of seconds
only small amounts of energy is released at a time
where do inorganic ions occur
solution of cytoplasm or body fluids of organisms
some in high concentration, others in very low
how are inorganic ions specific
each type of ion has a specific role, depending on its properties
examples of inorganic ions
hydrogen ion, sodium ion, iron ion and phosphate ion
what is the role of the inorganic hydrogen ion
determines ph of a substance
explain how the hydrogen ion works
presence of hydrogen ions lower ph
can affect enzyme function as it can change tertiary structure of enzyme and denature it
what is the role of the inorganic iron ion
component of haemoglobin
explain how the iron ion works
charged so binds w/ oxygen forming oxyhaemoglobin
oxygen is then transported
what is the role of the inorganic sodium ions
co transport of glucose and amino acids
explain how the sodium ion works
sodium ion moved out of cell by active transport which creates sodium concentration gradient
this affects water potential
what is the role of the inorganic phosphate ion
component of dna and atp
explain how the phosphate ion works
component of nucleotides
in dna found as backbone
used to make atp in condensation of adp
what bond does water have
covalent bond
what does specific heat capacity mean
amount of energy required to raise the temperature of 1kg of a substance by 1*c
what are the properties of water
its a metabolite
has high specific heat capacity
dipolar
large latent heat of vaporisation
strong cohesion between water molecules
its a solvent
density
what does water being a metabolite mean
involved w/ condensation & hydrolysis reactions like photosynthesis and respiration
what does ice act as
an insulator
what does water having a high heat capacity mean
buffers changes in temperature
can gain lots of energy without changing temperature
what does it mean if water is dipolar
acts as good solvent
what does it mean if water have a large latent heat of vaporisation
cooling effect with little evaporative loss
what does it mean if water has strong cohesion
cohesion between molecules
water can be drawn up vessel in narrow columns e.g transport in plants
produces surface tension
suggest a method other than a colorimeter used to measure the quantity of reducing sugar in a solution with precipitate
filter and dry the precipitate
find mass/weight
