Module 2.2 Flashcards
Look at the sheet for the strcutre of water , rememeber it .
-What is cotnained in a molecule of water
-A moleucle of water contains on tom of oxygen , chemicallybonded to two toms of hydorgen . Bonds between o-hm covalnt bonds .
Key about bonds in water moelcules
-In wter moelcules , the oxgen atom has a small NEGATIVE charge .
-The hydrogen atoms have a small POSITIVE chcagre .
-Because of these chagrers , scientists say that water is a POLAR molecule . And the oppoite charges means that the water moelcules are attracted to echother .
-these ofrces of ttraction are called HYDROGEN BONDS .
Properties of hydorgen bonds
-Hydorgen bonds are quite weak bonds .
-However , even a smll volume of water contains a LARGE NUMBER of hydorgen bonds .
-so they have a LARGE efect on the propertieis of water .
In liquid water …
water moleucles are not arranged neatly , instead , they aremoving ranodmly . HOwever , hydrogen bonds are sitll PRESENT .
Check sheet to see hydrogen bonds in a water moelcule
…
- propeties aND ROLE OF WATER
wATER H SA HIGH SPECIFIC CAPCAITY .
mening , WE HAVE TO PUT IN OR TAKE OUT A LARGE AMOUNT OF ENERGY OT CHANGE THE TEMPERATURE OF WATER.
- properites and role of water pt2
-When we heat water , the heat energy goes towards weakening or breaking the hydorgen bonds .
-Rather than incresing the kinetic energyof the water moelcules .
-Becuase of this , water acts as BUFFER against rapid temperatrue changes aka temperature of water tends to not change rapidly.
ALLOWING water to ct as a habitt , for aquatic organsims . As awautic organisms would not be able to function if the temperture of water changed rapidly . E.g hot/cold days .
If conditions are very cold ,
then water eventually freezes nd turns to ice .
KEY ; is ice is less dense than liquid water so ice flots and ice is also a habitat for a number of organsims .
-As well as this , ice also insualed the water below to prevnt it from freezin . This means that organisms can conintue to live int he water , udner hte ice .
Another important property of water is that it has a very …
HIGH latent het of vaporisation .
-What this mean is that it takes a larger amount of heat energy to evaporae water .
-This allows orgnisms to cool themselevs without losign a great deal o water . We can see this with sweating /
WHat hapens when you sweat
het enegry is used to evaporate water formt he surface of the skin .
-Ths transfer of heat energy allows the organisms to cool down .
Another really improtnt role of water (4)
Solvent;
Water is an excellent solvent , in other words , lots of subsances can dissolve inw ater .
-Both eukaryotc +prokaryotic cells contain a large amount of dissolved susbtances .
EXAMPLES; the chemicals inovlved in metanlic reactions such as respiration . As well as the enzymes needed to carry out these reactions /
Another really improtnt role of water (4) PT2
-Bodies of water such as ponds +river contrain dissolved oxygen + this is used by organisms living in the water to carry out respitation . Making wter an excellent habitiat for these organsims .
As water is sucha GOOD SOLVENT …
it can be used to transport substances .
EXAMPLE , blood plasma .
-Blood plasma the liquid par of the blood , this contains a large number of dissolved substances .
-INC , Co2 , MINERAL IONS SUCH AS THE sodium ion + the chemical suchs as glucose + amino acids .
Wter is a good solvent , how is this good in plants ?
-Water is also used to to tranposrt substancces int he xylem vessels of the plants , Water in the xylem contains dissolved mineral ions such s the magnesium ion .
Water tranpsort in the xylem part 1
Water in the xylem contains a dissolved mineral ions , such s the magnesium ions .
Water tranpsort in the xylem part 2
Magneism ions pass into the plant roots fromt he soil .
-They re transported in the xylm from the roots to the leaves.
Water tranpsort in the xylem part 3
Once in the leaves , the mgnesium ions re used to make chlorphyl for photsynthesi .
-because water is such a good solvent , it amkes an excellent tranpsort medium .
Another eally good PROPERTY of wter
-Water moelcules tend to STICK TOGETHER .
-Scientists call this COHESISION - this is due to the hydrogen bonds between water moeleucles .
-COHESION allows long columns of ter to travel in the xylem tube . Making water ideal s a transport medium in plants .
Cohesions lso causes SURFACE TENSIONS
-Where wter mets air , surface tension is suefula s it allows hte surfce o wter to act as a habitait (for insects like pondskater0
Final property of water !
-It is relaly improtnat in metabloic rections .
-E.g wate ris a reactant in amny differne trections .
These include hydrolissi rections and in photysntheis s.
-Water is also produced in certin metablolic reactions . These included condensation reactions aerobic respirations .
strucutre of glucose
learnt it ish
-Glcuose has a RING SHAPE
-formula is C6H12O6
-All carbohydrates inclduing glcose contain only the elements carbon , hydorgen and oxygen .
black underlines
–Shows glucose has SIX carbon atoms .
-Sugars with six carbon atoms we call HEXOSE SUGARS .
The strcuture of glucos ei scomplicted , so scientists use a simpler version . (CHECK SHEET)
NEED TO LEARN THIS STRUCTURE AS CAN BE SKED IN EXAM .
Glucose is a single sugar molecule
-Sciensits call single sugar moelcules MONOSACCHARIDES .
(mOno = one) (saccharide+suagr)
Examples of differen monosaccharides
-glucose
-galactose
-fructose
What is one property of monosaccharides ?
SOLUBLE IN WATERRR
-if we look again at the full strucutre of glucsoe we can see wh .
-Monosccharides , inclduing glucose hve aalrge umber of OH groups .
-Scientists call OH groups liek this hydroxyl groups.
soluble in water (2)
-hydroxyl groups can form hydorgen bonds with water molecules .
-Therefore monosaccharides are soluble in water .
-Scienitss cll moelcules like this hydrophilic .
-HYdrophillic mens water lvoign and hydrophilic moleucues ALL DISSOLVE IN WATER .
Some monosccharies contain five cabron atoms ;
-These are called PENTOSE monoscchrides .
-good exmpal e= RIBOSE .
CHECK SHEET AS WE NEED TO KNOW + LERN THE STRCUUTR OF RIBOSE /
Monosacchrides can be chemically joined to form larger crbohydrtes ;
scienitss cll these disacharides + polysacharides .
there are wo forms of glucose
-these two different forms are called isomers of glucose .
CHEK THE SHETT
-THE RIHT MOST CARBON ATOM IS NUMBER ONE.
-iN BOTH ISOMERS OF GLUCOSE of glucose , carbon 1 is bonded to a hydrogen atom .
-+ also to an OH gorup .
-remember sciensits call on Oh group a hydroxyl group .
Key differences between the two isomers
-is the potion of the hydroxyl group on cabron 1 .
chheck star one
-If the carbon 1 hydroxyl points BELOW the ring , then we call this isomer alpha glucose .
check star two
if the carbon 1 hydroxl point above the ring . Then we call this isomer beta glucose .
check disaccharide section ..
the two glucose molecule can rect together to form a disaccharide
Disacharides form when two mnosaccharides chemically react togehther .
-What happens when we react togthether two alpha glucose moelcules ,
the disaccharide we make is called maltose .
when we make a disacharide , we also produce a moleucle of wter .
-The water molecule is formed from a h yddrogen atom , from one of the monosaccharides + a hydroxyl group from the other . CIRICLED IN PURPLE ONT HE SHEET .
-when a r eactuib firs a water moleucl like this , scientiss call this A CONDENSATION reacton .
as we know two moleucles of alpha lglucose can rec togther to form the disaccharide maltose .
-In this reactionw e have formed a new chemicl bond between the to molecules of lpha glucose .
-This bond s called a glycosidicc bond . ( hve boxed the glcosidic bpnd in pink.)
-If we number , the carbon atoms , we can see , the glcosoidic bnd between carbon 1 one oe alpha glucose 1 and carbon 4 on the other (ciricled in pink0
SO WE CALL THIS A 1,4 glycosidic bond .
LEARN THE WHOLE DIAGRAM AS OUC OULD BE ASKED TO DRAW IN EXAM .
dISACCHARIDE ARE FORMED IN CODNENSATION REAXRIONS.
-A moeucle of water is produced .
-IF WE DD WATER TO A DIACCHARIDE , WE CAN BREAK THE GYLCOSIDIC BOND .
-This converts he disaccharide back to teh origional monosacharides . This ic alled a hhydrolysis reaction .
(normallyc rried out by enezymes ) .
s well as maltose , there are two other disccharides we need to learn .
sucrose = glucose +fructose
Lactose = glcuose +galactose .
-gLUCOSE IS EXTREMELY SOLUBLE INWATER.
-Contains a large number of hydroxyl groups .
-Hydorxyl groups re poalr due to the samall negatiive charge ont he oxygena otm + small posiitive charge on the hydorgen atom .
-Meaning hydroxyl groups can form hydrogn bonds with water moelecules .
However , due to its solubility ,t here is one BIG problem with glucose .
-If a cell congtains a large amount of dissolved glucose , this cna cause water to move into the cll by osmosiss .
How do we solve this prolem ;
plant cells store glcuose as starch .
STARCH: we find it starch grains .
-Strarch consists of two moleuvles called AMYLOSE AND AMYLOPECTIN .
Strucutre of amlose
DESCRIBE STRUCUTURE OF AMALAS - unbranched .
-Amlyose is a polymer of alpha glucose moleucles (tqo alpha glucose molecules molecules can join together disaccharide maltose .)
-glucose molecules joinbed by 1,4 glycosidic bond .
-condensationr ectoin s moelcule of wter is formed .
Key ; if we join togther a large number of alpha glucose moelcules , we make polysaccharides
(amylose canc ontain hundreds + thousnands or alpha glucse molecules , free sicl 1 .
alpha glcuose is joined by 1,4 glcosidic bonds , condnesation reacts bond is formed also porduces molecules of H20 .
-The amylose moleculle than twists into compct helix . With hydrgoen bonds forming between glcuose moelcues along the chain /
Starch is a store of glucsoe , so when the cell needs gluccose ,w ater is used to break down he glycosidi bonds .
check free scince videos this is a hydrolysis reaction .
Amlopectin is apolymer of alpha glucose . Joined by 1-4 glycosidic bonds .
UNLIKE amylsoe , amylopectin chains , have a branch , chery 25-30 glucose moelcules . 9Branchis just another chain of alpha glucose moelcules joined by 1,4 glcyosidic bonds .)
–The brnach is connected ot the mainc hain by glcysoicic bonds .(check statch part 2 free science lessons )
-
Amlopectin is apolymer of alpha glucose . Joined by 1-4 glycosidic bonds . part 2
-but in this cse , glycosidic bonds is inebtween carbon1 of one of the alpah glucos emoelcules + carbon 6 on the other alpha glcuos emoelcule .
-so it is claledd a 1,6 gylcosidic bond .
check shet fo simpified strucutre of AMYlopectin .
–can see it is a heavily branched molecule .
-Making amylopedtin differnt to AMYLOSE .]-As amylose is an unbranched polysacharide .
question asked in exam ?
HOW STRUCUTRE OF STARCH IS RELATED TO ITS FUNCITON ?
- PORPERTY OF STARCH
AMYLSO forms a tight helic , makng starch compct .
-AK starch can store a large mount of glucose mollecues for its size
- propertyof starch
starch is also insoulbe in wter .
-Meaning starch does not cause ater to enter the cell by osmosis .
-AS amylsoe and amlupoectin are polymers , they are too large to diffue throught he cell membrane and pass out of the cell .
what happens when a cell NEEDS GLCUOSE ?
-enzymes are sued to break the glycosidic bonds ins tarch . This is a hydrolysis reaction nd requires wter .
-Thr enzymes taht break downs tarch ac at the ends of the meolcule
-AS AMYLOPECITN HAS A LARGE NUMBER OF branches , IT EMANS IT HAS A LARGE NUMBER OF ENDS .
-tHEREFORE ,E NXYMES CAN BREAKDOWN STARCH RPIDLY /
What is the storage moleucle gluocse in animals
glycogen .
-glycogen is found in the liver and msnucle cells
What is glycogena polymer of ?
-*ALpha glucose ,
-mos of the alpah glucos emoelcues are joined by 1.4 glycosidic bonds .
-BUT ALSO CONTAIN BRANCHES - the glcuose moelcules at the branch are joined by a 1.y6 glcyosidic bonds .
glycogen seems to have the same trucutre as amylopecitn .
key differenc eis glycogen ahs more bbranches than amylopectin , making glycogen a very compact molecule .
As glycogen has a large number of branches i has a lot o free end .
Menain enzymes cn convert to gyclogen back to glucose very rapidly .
IMPORTANT ; as animals often hve a high rate of respitation , nd the energy needs of animals chan change rapildy .(animals may ave to move quicklybecuase of a predator)
-if that happened the rate of respiration woudl increase .
-Gyllcogen in the naimals msucls , could be rapidl converted ot flucose to be used in respiration ..
Glycogen is insoulbe in water
so glycogen does not draw water into cells by osmosis .
-Being a large moelcuels , glycoegn cnnot diuffse out of cell .
-All there featrues mke glycoegn an ideal glucose storga emeolcule in animal cells .
where is celluose a mjor part of
-the cell wl foudn in plant cells .
-struucture cellulose poluyer of beta glucose .
Key; Hydroxyl on carbon1 , points above the plane of the ring .
probelem ; if we needed to form a glysocosiidc bond betwen two crbon 1+4 .
-The hydroxyl groups are pointing in different reaction
problem witht he cellulose
if we need to form a glydcosidic bond between two carbon 1+ .
-yhr hydgroegn groups are pointing in different reaction .
-so when a moelcule of cellulose is formed .
-eevyr second beta glucose flip .
-now a glycosisic bond fan form etwen carbon 1+4 (don’t need to flip 3rd lpha beta) , any second .
-cellulose is an unbranched polysaccharide ..
-Cellulose forms a straight chain , without any branches allowing cellulos emoleucles to get close together .
-hydrogen bonds , can now from between neighbourign cjains .
-because a huge numebr of hydrognb bond form , it makes cellulose EXTREMELY STRONG .
when cellulose chins group together , scienits call this is a micorgibril .
micrfibrils then group together to form larger strcutres called macrofirills .
-Finally macrofibrils dan group together tof orm a celluloe fibre .
these cellulose fibres form a palnt cell wall .
key feature of celllsoe is strenfrh .
-stnregth allows cellulose wcell wall to cry out its unctions .
-the cellulose cell wall is also permeebale to moelcules good examples is wate r.
-the cellulose cell wall is also permebale ot moelcules good example is water .
-under nromalc onditiosn , plant cells containg a gret del of warer .
-as water moves in by osmosiis ,t he plan cells contenrs push outward agasint the cellulose cell wall.
-means it cn resist the outwall pressure due to cell contins ,
-Prebenting the plant cell from bursitn g.
part two LAST CARD ON CELLULOSE
-WHEN a cell is full of t , like this i becomes rigid , scientists say the plant cell is turgid .
-These turgid planrt cels helpt og ive the plant is urpgpiht trcure ,
FOR ALL THIS CHEKC IVDEO ON FREE SCIENCE OR STRCUTREU .
-Proteins are among the most important molecules in biology .
-proteins carryo ut a visit number of functions in lviing organsims.
-All proteins are formed aminoa cids ,
-20 diffeent amino acids found in biology .
-structure o aino acid .
-general strcuture
-three parts to an aminoa cid
-maine group
-cabroxyl group
-these two gorups are the same for any aminocid .
-R giryo –? differrent fo reach of the 20 aminoa cid .
two differen aminoa ccid are
r gorup for first si hydorgen
-r group fo rthe second one is a carbon atom onded to three hydrogen aotms .
-In the xam YOU COULD E ASKED TO TNAME TE ELEMNTS PRESEN TIN PROTIENS .
-THEY CONTRAIN thre rlrmrnyd
csarbon , hdyorgen , nitrogen + oxygen .
-Some amino acids also contrian the elemnt suflur .
Two amino acids forming aa peptide bond
-tehse two amino acid can react togyher + form a chemical bond .
-peptide bodn formed . Do need to know this .
-THIs is an exmpale of a CONDENSASTION rection ,.
The mioelcule that ws formed is clled a DIPEPTIDE , AS IT CONTAINS TWO MINO AICDS , BONDED TOGETHER.
+-this rectiont akes palce in riosomes , wich s where porteins are synthesised inc ells .
-This reaction is catlaysed ba specific nzyme .
-If we join three or mor eaminoa cids we make a POLYPEPTIDE .
-One meolcule of water is amde for every peptide bond ,we’re bond .
-I shouldpopojt out polypeitded often consits of hundres of minoa cids togher ,
-We can also REVERSE , the reaction + break the peptide bond , tod o that ,w e add bac a moelcule of wate r.
-This is called a hydrolysis of a rection .
-This rection is carreid out by portease enzymes int he digesitve styems .
difference between a polypeptide and portein
-in ordered to be calesed as a porien , a polypepetide has to fold into a comples 3 dimnsional shape .
-Once tje [pu[eotde js fpded omtp tje cprrec sj[ae . It cn carry out its fucions foe xample as an enzyme or a hormoene .
-At this point , we would rfer to it as a protien moelcule .
-Many proteins actull conits of several different poypetides .
-Forming a alrge + compex moeclule .
-+Proteins of concerins other moelcule s, helpign them to crry out there functions .
Lipids is the scienitc name for moelcules ofund in FATS AND OILS .
…
One fucniton of lipids
-Lipdis are a major source of energy in the human dier .
-We dinf lipids in oils sucha s olive oil + in solid fats such as butter both sources rich in eenegry .
Second funciton of lipids
-lIpids are also used to store enegry ,f or exmpale adipose tissue in huans .
-Aidpose tissue is found udner the skin . As well as acting as an energy store .
-The adipsoe tissue also heps to insulae the body reducing heatloss to the environemnt .
-AAlso can find adpiose itssue around itnernal organs sucha s the kidneys .
-Helping to portect the organs form injuryt .
third fucniton of lipids
Lipids are also sued as waterproofing ,f or exampel the oils which caot the fetaher of awuatic birds .
foruth function of lipids
lipdis are also a major part of the surface of memrbane ssuch as hose which surround cell s+ mitochodnira .
What are the two main categories of lipids
-triglycerides
-phospholiipds
check heet , what do triglyceridies cosnit of ?
a moleucle of glcyerol with three fatty acids .
check sheet for strcuture of a fatty acid moelcule .
-there are two key parts to the fatty acid moelcule .
-At the end there is a CRBOXYLIC GROUP , this plays n improtnat role when we form triglycerides .
-The rest of the moelecule consits of a long hcian of crbona toms bonded to hydrogen .
-This is ruroudned by fattya cids .
-saturated fattya icds contain a single covlent bond between the carbon aoms .
-CEHCK SEE TTO SEE .
check sheet to see an unstaturated fatty acid .
-As youc an see , unsaturated fatty acids have one double covalent bond beteen the carbon atoms .
-tHIS IS A MONTONOUS SATURATED FATTYA CID AS THERE IS ONLY ONE DOULE COVALENT BOND IN THE CARBON ATOM .
-This fatty acid has two doule covalent bonds in the carbon chain . So , this fatty acid is polyunsaturated .
Formation of triglycerides (check sheet for strucuture(
As you cn see , trigluceries re formed from a moelcule of glycerol and three fatty acids .
-underlinded is the thre hydroxyl gorups .
check hseet and video
-a moleucle of glycerol and three fattya cids can react togther to form a bond
-an esterbond is also formed .
This process is called esterificiton and wate ris also formed in the porcess so is an exmpale of CONDENATION REACTION .
-we can carry out this reaction with two or more fatty acids .
this is the strucuture of a triglcueride moelcule .
HOw ar dats + oils a mojor spource of energy in the huamnd die t?
-IOn the digestive sytem , ipase nezymes break up the esterbond , releasing the glycerol + datty acid moelcules .
-This reaction requries three water meolcuels and is an exmaple of a hdyrolsyis reaciton .
Trigclycerides are NON-POLR moelcules .
-Menain that they ar hydrophobic , in other words , they do not dissolve in water .
-Expalining why trigolycerides are used as waterporofing in aquatic birds .
As triglcyerides contrain a large amount of carbon + hdyrogen atoms…
A greta deal of enegry can be releaeed from tirglycerides .
Phodpholipids strcuture similr to triglcyerides.
-Phospholipids have a strucutre which is simialr to triglcyeirdies but is differen tin one key wy .
-this differenc ehas a major effect ont he way phospholipds behave .
strucutrue of phospholpids
-A glcyerol moelcule bonded to two fstty acid moleucles .
-The glcyerol moelcule is also onded to phosphate . DONT need to know the strucutre of phospahte , just know i is negaitvily charged (check sheet) 9AKA THIS PART OF THE MEOLECULE IS POLAR) .
-Becaus eof this , the pshosphate gorup is hdyophillic (it attracts water aka) .
Inrl phospholipd sare more compliacted , however ,w e can draw phospholipids ina simpliefied wyz (check sheet)
-Head is the polar hydrophillic part of the meolcule .
-The tail is meant to represent the TWO FATTYA CID MOELCULES , remembrer htese are non-polar +hydrophobic .
Phospholipdis contain both a hydrophillic +hydorphobic region .
-Meaning phospholids behave very differnelty in water compred to triglycerides .
In wter , phospholipd molecules , position themsleves so that the hydorphillic head gorups can itneract with the water moelcules .
-While hte hydrophobic tails clsuter together ,w ell away form water moelcuels . SCIENITSTS CALL THIS STRUCUTRE A PHOSPHOLIPID BILAYER .
-This property of phospholipds is extreemley sueful . As it allwos phospholids to form memeranes that we find oth around cells ++ within cells .
Cholestrol - need to be able to describe the properties + fucntion of cholestrol .
-Choelstrol is part of a famil of lipdis called STEROIDS .
-does not looka ntyhign like triglycerides/phospholips and do not need ot know the strcutre .
Check sheet - what are they key fetures of cholestrol
-the hydroxyl group (HO0 is hydrophillic .
-Howevefattty acid tails . r , the rest of the molecule is hydrophobic .
THIS MEANS , that cholestorl can insenrt into cell memebranes .
-The hydrophillic hydroxyl gorup on the hcolestrol moelcule cn interact iwth the head groups of phospholipds . While the rest of the choelsreol moelcule can intreacys with the hdyrophobic
one role of choelstrol
-choelstrol plays a key role in controlling the fludiiuty of cel memrbanes .
Cholestrl plays a number of critical roles in living organisms (1)
-It is the starting point for a range of HORMNES . (including oestrogen and tesoserone).
-As they are base don cholestrol m these hromones can pass through cell memebrans + interact with other receptors inside he cell .
Cholestrl plays a number of critical roles in living organisms (2)
-Cholestrol is used int he body to amke vitamin D .
-This takses place in the skin in resposne to UV LIGHT .
-Vitamin D is needed for for the proper development of bones .
Cholestrl plays a number of critical roles in living organisms (3)
-Cholestrol is used in the liver to produce Bile .
-the fucniton of bile is o increase the rate ofdigestion of lipids by the enzyme liapise .
Why do we test for biological moelcules ?
-We oftn carry out these tests to see which chemicls are present in foods .
-As WELL S OTHE RPORCESSES –> WE CAN TEST FOR STRATCH IN PLANS TO SEE IF THEY HAVE CARRIED OUT PHOTOSYNTHESIS .
–> WE CAN TEST URINE FOR POTEIN , TO DIAGNOSE KIDNEY PROBLEMS .
–> TEST URIEN FOR HYLUCOS ETO CHECK FOR DIABETES .
