3.8 Onwards Flashcards
Where is peptidoglycan transferase found
In RIBSOMES.
Nucleus acid context
Was discovered in cell nuclei so that’d why they were given this name , two types dna and and rna and both have roles in storage and transfer of genetic information, scythe did for proteins and basis for heriditwryn
What makes a nhcelic acid a nuclei acids
Nuclei acids are polymers from nucleotides l every nucleotide has
- a pentose monosaccharide = either ribose or deoxyribose
- a phosphate group
- a NITROGENOUS BASE
Thus all elements are C, H, O ,P and N !
More on ntitigounednbade?
Nitrogenous base contains either one or two carbon rings and hss nitrogen
How do they join
Nucleotides join by condensation reactions forming covalent bonds
These happen between the phosphate group of one nucleotide which is connected to the FIFTH CARBON and the hydroxyl group of another nucleotide in the third carbon
This makes ohosphodiedyer bonds
Sgsin phonation grouo on 5th carbon connected to hydrolysis group on third
When they join like this they make a long chain of nucleotides that from the sugar phosphate backbone m which is only broken in hydro lido
5’ 3’?
The the first top bit will be 5’ as it starts here and ends at 3’ , the other chain of nuckeoditded will be from 3’ to 5’ AS THEY ARE ANTIPARALLEL
Now specifically for DNA = DEOXYRIBOSE NUCLEIC ACID?
= pentode monosaccharide is DEOXYRIBOSE ( and its ribose but without one oxygen. )
- phosphate group
- and can have between 4 nitrogenous base sugars = adenine guanine cytosine thymine
Ribose vs deoxyribose
Both have hydroxyl group on OH on carb 3 which necessary for onophiduedyer
It ribose had a O on csrbknn3 Sewell , deoxyribose DOESNT!
The 4 nitrogenous bases can be split into purines and purdimsidined bssed on how many csrbknnringd they have (1 or 2) which ones
Basically if it has Y so cytosine and thymine , then pYrimidine !
If no y then purine
PURINE ARE PURE SO THEY ARE BIGGER , this means they have a DOUBLE CSRBIN RING STRUCTURE
And thus pyramiding has single carbon ring structure
So it onyl binds from purine to pyrimidne so pure is adenine guanine and bigger and they bind to thymine and cytosine smaller sndnoruinidne ?
Why are AT AND CG COMPLIMENTARY TO EACH OTHER ?
because they may a specific amount of hydrogen bonds with each other which couldn’t happen another way
- purines bind with oyrmidines so AT and CG , thryncomplimentsry becaude they form specific amounts of hydrogen bonds here
AT = 2 CG = 3,
What is the actual arrangement of nucleotides dna nuclotidesin a molecule of dna ?
- made from two strands of polynucleotides (oh yah multipe nucleotides join to make polyneucletoudes .
- two strands are coiled to make a DOUBKE HELIX , where both strands are comolimenttaily base paired , with hydrogen bonds in between
- the. Two strands run opposite to each other and thus are antiparallel, this is thronly way they can successfully pair and be srrnsged
- here this is 5’ to 3’ and then then anitparallel is 3’ to 5’
So start from I discuss nucleotides that join by phosphodiedter bonds, thennteo dtrsndshydrogen bonds complimentary and sntiparlalle thstbcoil to make a double helix ,
Why is base pairing properties importemt
The pairing between bases allows DNA to be copied and transcribed EXACTLY - and these are key properties required of the molecule for heridatwy , if it bonded differently each time it would not be able to perfection transcribe etc
Now that we have our genetic information stored in sequence of bases, how is this transferred = WHAT IS RNA
ribonuclease acid
- nucleotides still
- with a phosphate group,
- ribose pentose monoscshride (had whole OH on carbon 2)
And also nitrogenous base
- this can be adenine guanine cytosine but not thymine, replaced by URACIL when copying
As thymine was pYrimidine with singl carbon ring, so is URACIL!
this transfer needs to happen because dna to bug snd two ssvrednto leave and come back each times so a section is copied and used instesd
This is transcribed into a messenger RNA and thus mRNA molecule
And the fact AT makes 2 AU makes 2 hydrogen bonds too, the fact this happens means base pairing rules still apply and copies are cal,
Here indifuak RNA nuekcotides also join in exact same way by 5 and 3 pjophodiedter bonds
Once dome
What happens once finished
RNA molecule degrades in cytoplasm , where lhosphidetder bonds hydroksied snd rna nucleotides released and reused
KEY DIFFERENCE =
KEY DIFFERENCE BETWEEN DNA AND mRNA
DNA IS OF TWO STRANDS, MRNA ONLY ONE!
Why still complimentsyrb
As it still makes 2 hydrogen bonds, it emsns suit is still coplemit entry
How do DNA extraction from plant material and why , what does each step do?
1) grind sample with pestle and mortar
- grinding will BREAK DOWN CELL WALLS
2) ADD either DNA extraction buffer or constituent home made ones , this contains = detergent , salt , protease enxumes
- the detergent interferes and breaks up cell membranes due to structure cussing them to form little micelles and break up like fats . This releases the Contents of the cell out into the solution
- now yius dd salt, which breaks the hydrogen bonds between the DNA and userounfing Ayer
- then you add protease enxumes , and these breakdown the HISTONE PROTEINS dna is wounded with , now you have dna free
3) at this point filter than add ICE COLD ETHANOL INZ
- this causes DNA to predeipate out of the solution
- and DNA is no longer protected here ss it is exposed so the soil keeps it protected
5) ss if precipices, ectrsctnusing dolit at angle without damaging
Explanation sgsin
1) use a pestle snd Mortar to crush the sample and this removes cell walls
2) now add detergent - this breaks down cell surface membranes by interfering with steufture, causing content of cell to be relesded into the mixture
3) now add salt which breaks hydrogen bonds that are made between dna and water
4) now add protease enxumes and breaks down his tone proteins in between , exposing dna from not being as compact
5) pour it in to a COLD layer of ethanol, which caused the DNA to predicate out, and ethanol protects
6) use splits to extract st angle to not damage the dna
You could do it better by hosting first to cause proteins to denature already +
How to do it there?
Heat and this caused protease to break down etc , can also use RNAse which will cause rna to break down too
Why need to denature enxumes?
Stops any enxumes from actually breaking the DNA instead
Why do cells require energy for in three typed?
Synthesis = large molecules such as proteins from small require energy
- transport = pumping molecules or ions across cell membranes for active transport
- movement = protein contractile fibres in muscles to cause movement
How is energy supplied
Through ATP , adenosine triphoohste , which is a nucleotide that easilky gives energy
Steufture ATP = Remember it’s a nucleotide ?
= - pentose monosaccharide which is ALWAYS RIBOSE
- nitrogenous base which is always ADENINE
- and three phosphate groups
= adenosine (adenine and ribose ) triphoohste atp
Why is ATP called universal energy currency! Is it just human “
No it is the molecules used for energy transfer in ALL LIVING THINGS, not just humans
Why do ATP not make chains ?
Three phosphate groups negatively charged and close so will repel each other
- this makes it unstable , so chains couldn’t be ,ade, but useful too as you can use thidnproteryb
How does ATP release energy overalls
Small amount of energy used to break bonds but large amount for energy released when that phosphate group reacts with other stuff, so overall more energy relessed
This can be thought as energy releasing from the bind breaking to generalised , nit technically but by
How is atp cycle happen
Energy from respiration using products like glucose or lipids etc isn’t used straight away , the energy is used to convert ADP into ATP in ohodohykstion reactions , this used energy from respiration and almost stored it here, in condensation reactions
Then when energy needed by cells, the phosphate bond “breaks and released the energy”, and this required water , so hydrokysidn, and this only happens with other revstuond rewuirijg energy snd they are coupled
Respiration energy used to phoohykside and make atp in cindesnrjson
When needed nhdrolysis releases energy
Reason for this is because getting energy from there is hard and stored in ATP first
Why atp still used even if can’t store that much energy
Can’t store that much energy , unlike csrbihdyrsted or domething , but rapid ply reformed by khidohykisatuonn, meaning for a decent amount of ATP they don’t all need energy , but rather it is a good IMMEDIATE STORE that has other benefits
1) small and can easily move in and out if cells
2) UNIVERSAL , universal store of energy you can use for anything I’m body , and professes could be different if different energy stieesused each time
- it is SOLIBULE and can deliver energy to aqueous environemtd
- here’s main - RELEASES ENERGY IM SMALL AMOUNTS , WHOCH MEANS LESS ENERGY LOST SD WATSE LIKE HEST FOR WHEN NOT NEEDED (like glucose would rrlesdetoo much energy and this goes to ester ), and thus cells get EXACTLY WHAT THEY NEED
- easily regenerated rapidly by respiration do effeicnet too
And thus good immediate energy store
Again main
Released energy in small mskiutnd and less so energy jot wstded unlike glucose, d,all can fit everywhere, soluble for aqueous , UNVIERSAL for whole body, essilky regnerated by respiration so good , and energy small enough for cellular reactions but don’t wastes, do good universal currency
Good immediate too because energy given off instantly due to instability wheress kthers may take tike , and this is ebvause onionykstioj and hydroksied of aaatp happening all the time do energy given and restored , so more immediate, but none goes to waste too so makes Dinesen why to sue
DNA replication semi conservatively - what does this mean
This means that for eshc new molecule of dna it had half the old strand and half a new stand , so one old and one nee, so semi conservative
Why is this dine
Ensured that if mistakes are made the amount if these are reduced, as there will always be at least half the molecule correct , and that can salvage something
How is DNA replicated then with enzymes etc?
DNA must unzip and break hydrogen bonds, free nucleotides match up comokineyrsiky , then hydrogen binds remade and then phophidedter bonds but how does this happen
1) DNA helical enzyme travels along DNA backbone and catakydes reactions that breaks hydrogen bonds between the two strands - unzipping
2) BOTH ACT AS TEMPLATES lnow free nucleotides in the nucleus line up comokinetsriky against the exposed section of strands . Hydrogen bonds are then REMADE
3) finally DNA polymerase catalysed the reactions to make ohophiduedter bonds between the nucleotides again , creating the sugar ohojate backbone
Okay polymerase first then hydrogen
What is continuous and discontinuous variation , limitation of DNA pilymerase, how is this overcome and what is called, what enzyme is used snd what are stands called etc
- problem = DNA polymerase can only catalyse resctions to make phophodiedter bonds in the 3’ 5’ direction , attaching to the 3’ end . So it can only move in the direction of this location
- for the strand that goes in this direction , as the DNA unwinds, this is fine, the polymerase can just keep on catalysing revsvtions as strand continues to unzip and is fine. This is the LEADING STRAND And Undergoes CONTINOUSE REPLICSTION
- however other strand running from 5’ to 3’ end had to wait for a decent enough section to unfold first , before catalysing revstuond in the little 3 to 5’ , but then wait for snither section to open up. Thus it catksyded in fragments , known as Okazaki fragments . This is the LAGGING STRAND AND UNDERGOES DISCONTINOUS REPLICATION
in order to fix this, DNA kinase ensyme cstksyded resctions snd makes ohophdiedter bonds between Okazaki fragments ,
why can’t it just open all the way first and both happen?
- dna helcisde will break hydrogen bonds for the SHORTEDT time possible so that dna isn’t exposed as this increases chance of days,e, that’s why it does it as we go along, reokcistionnsnd unwilling st the same time so dna is proretcetd !
What is a mutation
Although dna relkcistionnshd to be really accurate to ensure generic information is conserved it can slip up. A mutation s an error in the cooying of dna in a strand. These are RANDOM and spontaneous and lead to a new chain
= a RANDOM ERROR IN THE DNA BADE SEQUENCE after replication
What is the genetic code
The fact that dna is what codes for all proteins in any animal, and that oroteins are based on a sequence of amino acids, then the dna must code for the sequence of skink acids , and this is the genertic code
It is the the sequence of base triple tee that code for amino acids for protrind, and this is present in all organisms each and every one ,
Three features of the genetic code = degenerate , universal and non overlapping
What does universal mean
Each codon ever coded comes from a base triolet, but this will be the sa,e for all organisms in the world, same triplet codes for same amino acid.
Also the fact that all organisms have the same 4 bases shows genetic code is universal
Genetic code just means?
That bases on dna codes for the amino acids of proteins for all organisms
What does degenerate mean
For evrything 4 baded means there are 4 x4 x 4 combinations possible , so 64 possible codons inckudijtna start and stop codon , yet there are only 20 amino acids to code for in the human body that makes all our proteins
The fact that there are MORE combinations then amino aicds means that more than one combination codes for the same amino acid,- this is known as the genetic code being DEGENERATE
- advantage
What advantage of being degenerate
Good becaude if mutation occurs that only changes one bsse, high chance it couks still code for the SAME AMINO ACID , and so no effect actuallyhappens, because there are more than one combinations for the same amino acids !, so chance of damage from mutations is REDCUED
What does non iverlapping mean
The fact that there is A START CODON means dna is always read from the first base and gied in threes after that, not from base 2 or 3 which WOUKD RUIN EVERYTHING this also helped by having a STOP CODON , So dna read ecstasy hoe it should be codon by codon
Thus non overlapping
