Biology (Biological molecules) Flashcards
metabolic reactions are?
sum of all chemical reactions in body
catabolic reaqctions are
break down larger molecules into samller oens
anaolic reactions are?
build smaller ones up into lagrer ones
monomers and polymers?
thousands of monomers make up a polymer
respiraion where you break down glucose is a?
catabolic reaction
Animals and plans have enzymes that onyl break down?
alpha glucose
carbodydatrets are?
properties
sugar units
soluble in water/form crystals
names by?
number of carbon atoms e.g. 3-carbon>triose
glucose is ?
hexose sugar
general formula of carbohydrates?
CnH2On
differences in alpha and beta glucose strcutre?
al;pha glucose OH and H same on both sides
beta glucose- oppsotite on either side
joinging 2 monosacchairdes in a condenssation reaction makes a ?
dissacharide
starch is?
1-4..?
water potential?
dense?
1-4 glycisidic bonds
mainly straight-chained amylose which can form helical chains>coil so pack desnely pack repitaroy substrates
hold ,pre per unit volume
insoluble- not affected by celluakr water potential
glycogen is?
1-6..?
solule?
quicly relseae enrgy?
1-6 glycosidic bonds
branched>can’t compact closely together>hold less energy per unit volume
ut can relseae energy quciker as more readiyl hydolsed by enzymes
soluble- can affect cellualr water potential
cellulose
parrallel chains?
beta glucose?
Beta 1-4 glycsidic bonds
moelcules form hydorgoen bonds with neighbouring moolecule not itself, so they lie parrale to each ohtrer with hydoyl groups alternately (180 degrees) between each
insoluble- doesn’t affect water potential
several bundles fo moleculs lying parrael are?
microfibrils
Several microfibrils join toether to make?
strength?
guard macrofibrils?
macrofibrils
whcih priovde great emchanical strength and suppro to cell wall
cross-links to provde supprot
contorl fucntions e.g. guard marcofibrils allow opening/clsong of stomata
lipids are?
molecuels that contain carbon, hydroegn and oxugen
insoluble in water
lipids are used in?
membranes/ hormoens like choelrterol
glycerol and fatty acids make up fats/oil..glycerol is always?
the same but fatty acuids differ
essential fatty acids means?
can’t build up in body>take in as part of diet
saturated fats means?
unhealthier
solids at..
as much hydrogen is joined as possible is hjoined so solid at room temerature
animals contian a lot of these
unhealthy
unsaturdtaed fats mean?
kink
fluid
C=C- nt all hydoegns are joined
held looslely- more fluid>tend to be oils>more in plants
healthier
kink in fatty acid chain
Tricgkyercide is?
3 faty acids + 1 glycerol molecule
Properties of triglycerides?
soluboltiy?
energy strorage?
thermal insuakltion?
repel water molecules>hydorphobi -not elctricla charge
densely pack substtares- energy stroage
insolubel- nto afected by water potenil
thermakl insualtin in tissues (adipose tissues)
phosloipids are amde up of?
2 fatty acids+ 1glycerol + 1 phosphate group
why is the phospate ‘head’ hdrophilic?
attratced to water moeciles
0 has delta negative charge on it- attratced to dleta positive charge on hydogen atoms inw ater molecules
fatty acid tails are?
hydrohobic- inner bit of membrane- repel water while hydorphilic heads stay ont he outside of membranes close to wtaer
phoislipids make up the?
bilayer (membrane)- seprate cell contents/les substances diffuse in/ cell signalling
fatty acids may be?
cold climates
unsaturated- membrane is mroe fluid- in colder climates- this is ideal in low temps
saturated- more solid- less flexible
Animals in colder climates have?
thick layer so adipose tissue (triglycerides)storage moleules- store vitamin A and D
phos[ahes can ahve carbohydrate?
chains attached to them- cell signalling
Choeleterol is a ?
diffusion
fludiity
lipid hormone
- dissuse starght thorugh bilayer though simple diffusion
- sits in between fatty acid tails>stabiltiy
hgih levels of Cholesterol means?
bile
inner linigns?
lumps.gallstones
innerlinings>desposits>atherclesosis
Proteins are ….. joined together yb thousands of?
polymers
monomers- amino acids
strucure of amino acid has R group..?
differnt for every amino acid
20 of them- each amino acid in chain- possiblity out of 20
amino acid in plants?
maunfacure them from niortates in soil
essenail amino acids for animals?
vegetarians- protein source?
some digest amino aicds.buidl up proteins
some we can’t build up- have to take them in diet like meat so important vegetarians find proteion souce e.g. soya beans
What happenms if too many amino acids
toxic- have to be remvoe dby deanimation
protein is?
one or more polypeptide chains joined together
called amino acid residue as?
enzymes?
ezymes that break down protien are?
some removed in condesnation reation
covalent bonds are very strong- enzyems haev to catalyse reaction in condensation/hydolsis
protease enzymes- digest food, hormones- vital so effects arem’t premamnt, aging- skin loses elacsitiy/ability to rebuild collagen
proteins/polypetides aresyntheised on?
ribosomes-deterined by mRNA orders the amino acids in a partiuclar sequence
differne protiens- differnt mRNA has to pas throgh ribosomes
pimary strucure is?
basic sequnce of amino acids
seocndary strucure is?
amino acids coil or fold to form alpha helix or beta pleated sheet hydogen bonds (N-H and C=0)- weak but many togther priovide strength
tertiary strucuture is?
vital to funciton?
alpha helix/beta pleated sheet fold on themsleves to form 3D shape.c Held togethr by many bonds
vital to strcuure e.g. hormone must have complemntayr shape to receptor
Bonds in tertiary strucure? disulfide ionic hydrogen hydrophilic/hydrophobic interactions?
disulfide- amino acid cysteine- between sulfur atoms- covanlent
ionic- oppsitely chargfed R groups near each other
hydorgen- delta positive and negative (N-H and C=0)
hydorhilic/hydrophobic- amino acids inwards and outwards in a water-based environemnt
Ehat happens if hea is appleid to tertiayr structre?
kinetice enrg cuases bonds to vibrate>brekas some of them (wekaer ones liek hydorgen/ionic bonds)>distorts the 3D shape
ebough heat is applied>strucure will unravel) protein becomes denatued (stops functioning)
Quaternary strcuure is?
protien with more than one polypeptide chain or a one and an inorgainc component
haemoglobin has quaternary strcure
subuntis (chains)
prosthtic group
4 polypeptide chians/sub-units 2 alpha/ 2 beta prosthetic grop - Fe 2+ haem group globular ptotein- metabolic roles/soluble in water alpha helix
How ia the atrcuure of ahempglobin adapete dto its function
3D tertiary shape- carry oxygen to tissues
haem group can bind to oxygen
4 haem sites- bidn up to 4 oxygen molecuels
oxygen + haempglobin > oxyhaemoglobin
transport oxygne to repsiring tissues
3D shape-no nulcues so can pack full of haempglobin/large SA so can carry ltos of oxygen
Collagen is a ….. protein so is……in water?
fiborous protein- strucural roles- insoluble inw water
Collagen is made up of?
popypptide chains
left-handed alpha helix?
amino acids?
3 poplypetide chains wound in a left-handed helix strucure (makes it more fiborous)
35% of glycine, proline, alaline
How does the strucute of collagen adaopt it to its function?
hydrogen bonds?
covalent bonds
cross-links
hydrogen bonds wihthing heli strucure- strength
collagen molecuels form cross-links with neighbouring ones addign strenght/stabiltiy
cross-links are staggered- adding strength
What is collagen’s role in body?
tendons (made of collagen) attach skeltal muscle to bones
cartilage/connectiove tissue- provides strenght for trachea/bronchi
inner walls of arteries- blood at high pressure
Starch test?
add iodine
changes form yellow/brown to blue/black
reducing sugars test?
colourimeter?
calibration curve?
bendicts soltion (copper ll sulfate)
changes to red ppt
more preicpitate ther is tell how much bendedicts solution used up>filtrate it
put contents into cuvette>put in sample chamber>photoelectric cell picks up light [shows reading of light passed through)>more benedicts solution used- less light will be blocked [ light transmission increases]
plit a calibration curve of concentration of sugar (x axis) agaisnt % light transmission (y axis)
non-reducing sugar test?
2 samples- beendicts sotution0 make sure there are no reducing sugars
if not- boil other with dilute hydrochloric acid>solits dissacharides (like sucrose- non-reducing sugar) into its monosaccharides (glucose and fructose)
carry out benedicts solutin again>postivie
lipids test?
dissolve in ethanol
shake it with ethanol>decant into test-tube>cloudy white emulsion
proetins test?
biruet reagent
add it in equal voume to sample>down side of test-tube
blue ring>dissolve to violet colour
water is polar so?
electron density
hydrogen bonds making/breaking
unssymetircal electorn density
continaulyl maing/brekaing hydroge bonds- moving around
What does the strong hydrogen bonds mean in relation to keep large bodies of water stable?
becaus ethye makes bonds that are hard to break>needs a lot fo heat energy to heat up it
large bodeis of water liek oceans need a lot of heat energy>stay fairly stabke>provide a constant environment for organims
What does hdogen bonds mena in terms of freezing?
ice?
as you reduce temp>less kinetic enrgy>move around less>don’t breka bonds as easily
held in a solid semi-crystalline strucure called ice
less dense than water>floats on top of water>insulates water below so sustains life under water
habiat for polar bears (floating ice-packs)
What does evaporation from surface of water do
humans?
cools it- keep temp constant
humans- sweating/dogs- panting
cohesion forces due to hydoregn bonds mean?
plants?
stick toger-pulled pu as pne continous colum
xylem vessles.used to trrasnprot water up plant
wate provides a medium like?
blood (humans) and vascualr tissue (plants)
as water is polar when polar molecules ..?
metbaolc processes?
mix>dissolve as delta postiive oxygn and delta positive hydrogen cluster round oppsotie parts in moelcules_keeops them seprate
once dissolved-move around freely>metaboli processes
e.g. ions (minerals/vitamins) dissolve easily>respiration/hotosynthesis
Nucleotides are?
Monomers of nucleic acids
DNA = deoxyribonucleic acid
Components of nucleotides are?
Phosphate group
5-carbon sugar
Nitrogenous bases
Condensation reactions?
Form between phosphate group (loses a hydrogen off 1 hydroxyl group) and sugar
Sugar and base
Strong covalent bonds in nucleotides and between them to join chains together
As nucleotides are bonded together?
Repeating sugar-phosphate backbone with bases projecting inwards
Sequence of bases that provide the coded information in DNA
Only sugars that are?
The same bind together so nuclei acids can only be DNA or RNA
DNA is?
Double stranded
Purines- adenine which matches to pyrimidine thymine
Purine- guanine which matches to pyrimidine cytosine
RNA is?
Single-stranded
Purine- adenine matching with pyrimidine uracil
Purine- guanine matching with pyrimidine cytosine
In DNA the two strands?
Coil together to form a double helix
Thy are said to be anti?
Parallel as the two strands run parallel but opposite to each other
Left-side goes 5(prime)>3
Right side goes 3(prime)>5
The space in the middle is the same due to the ….?
These bases re held together by …?
Bases projecting inwards
Hydrogen bonds- gives them strength
3 between C and G
2 between A and T
DNA semi-conservative replication process ?
cell undergoes mitosis- a phase DNA replication
2 copies produced
1) DNA helicase breaks he hydrogen bonds and unwinds the double helix
2) this exposes the bases (DNA codes)
3) free DNA nucleotides bind to complementary bases
4) DNA polymerase links them by forming phosphate diesther bonds with nucleotides
5) seals the backbone- happens on both parent strands
Why is it called semi-conservative DNA ?
2 copies are produced
One is parent original strand one is newly synthesised strand
Parent one provides template
Mendeleev and stahl experiment
14N
N 14 is higher Centrifugation- spin tubes round Force- heavier atom are pulled downwards/ lighter atoms go to top Limitations Sugar- same concentration Spin same speed Spin for same amount of time
DNA molecules are very long as?
Hold a lot of information - form of DNA codes
Double helix structure provides stability
Hydrogen bonds allow for easy unzippig
RNA is different to DNA ?
Riboxynucleic acids
Base is uracil
3 forms of RNA
Steps of mRNA copying the DNA?
Sequences of bases in DNA > amino acids > proteins
1) DNA nucleotide sequence that codes for a particular protein can be exposed by splitting of hydrogen bonds and DNA helicase
2) RNA nucleotides copy the exposed sequences/gene (multiple sequences of nucleotides) to form a complementary strand- complementary base-pairing=mRNA
3) mRNA leaves nuclear complex via nuclear pore and attaches to a ribosome on the rough e.r
4) rRNA reads the mRNA 3 bases at a time (translation- 3 nueotides=1 amino acids)
5) tRNA (transfer RNA) brings the amino acids in that order to ribosomes
Peptide bonds are formed to make polypeptides and proteins)
Gene is?
DNA sequence (multiple nucleotides) for coding for a polypeptide
What are enzymes?
What do they have in common?
Globular proteins/soluble/catalyse metabolic reactions/catalysts
What does a catalyst mean?
speeds up rate of reaction without undergoing any permanat change itself
Exracellular or?
At outside cells
Intercellular (act inside cells)
Enzymes have an active site which is?
Cleft which a substrate molecule will fit into complementary shape
Lock and key> induced lock and key
Substrate (key) fits into the active site (lock)
Induced fit- active site changes shape to fit closer round substrate when they collide/oppositely charged groups also make it hold
Change destabilises substrate molecule- easier for reaction to happen
Enzyme-substrate complexes ?
Different shape to active site so move out
How do enzymes reduce activation energy?
Hold the enzymes in a way that makes it easier for reactions to happen-sufficent
Lower temp
How does heat effect enzymes?
Intially increases rate of reaction- increased number of collisions- more with sufficent energy
Optimum temp
After rate decreases as kinetic energy makes bonds vibrate- break hydrogen/ ionic which hold tertiary struxure - unravels- active site chanea shape
Why would the rate of reaction go to 0 if keep increasing temp?
Eventually enough bonds break 3d struxure unravels denaturation enzyme stops working
Enzymes affected by pH?
What is pH?
Measure of H+ concentration
Negatively charged amino acid are attracted to H+ ions
Intiially rate of reaction increases - cluster round the amino acids- makes the substrate fit better
7 - optum pH- bet complementary shape
Increase it past 7 starts to decrease as active site changes shape- doesn’t got as well- lead to denaturation
Increasing substrate conc?
More substrate molecules - more for active site to catalyse- more enzyme-substrate complexes formed
Plateau /level off- if all active sites are being occupied- doesn’t do anything
Enzyme concentration has to be fixed
Increasing enzyme conc?
Intitily increases - more available- more complexes being formed
Plateau off- all substrate molecules are being catalysed at a fastest rate as possible
Substrate conc has to be fixed
In both these enzyme and substrate concentrations are ?
Enzyme conc in cells are usually?
Limiting factors
Marinated at low level
Competitive inhibitors are?
Inhibiton = decrease the rate of an enzyme-controlled reaction
Competitive- similar shape to substrate so can bind to active site- reduce no of complexes- produce enzyme-inhibitor complexes
If increase substrate conc- substrate more likely to bind- better fit but if increase inhibiton level more likely to bind more chance in collisions
Temporary bind to active site or permanently bind
Te
Non- competitive inhibitors ?
Bind to other place away from acitve site - alter tertiary 3D shape- change active site shape so substrate doesn’t it in anymore- reduces complexes
Increasing inhibition increases decreases rate if reaction further
Increasing substrate conc doesn’t do anything as it doesn’t bind to active site
Temporary or permanent
What are coenzymes?
Organic non-protein molecules Bind same time or just before substrate Recycled back to help with reaction Carry chemical groups between enzymes in a sequence Eg coenzyme A- aerobic respiration
Prosthetic groups?
Permanent coenzyme
Interfere with tertiary 3D shape so vital to function > properties
Eg haemoglobin
Cofactors?
Inorganic ions
Combine with enzyme or substrate to change chars distribution or shape of enzyme-substrate compexes to make form easier
Eg amylose enzyme starch>maltose only if cl- ions are present
Metabolic poisons- inhibitors?
Potassium cyanide
Inhibit cell respiration- inhibs enzyme cytochrome oxidase in mitochondria
Build-up of lactic acid in blood- cause people to die
Medicinal drugs-HIV?
HIV needs protease enzymes to build new viral coats- reproduce
Protease enzymes acts as inhibitors to viral protease enzymes so stop them producing complexes- can’t reproduce
Antibiotics- inhibitors?
Pencilin
Bacteria-cause infection
Bacterial enzyme forms cross-links in cell walls- cell walls are made of polysaccharide materials/cross-links provide support
Penicillin-similar to bacterial enzyme- fits in cell wall- slightly different so makes it weak>falls apart- bacteria can’t reproduce- competitive?
