Chapter 3.8 To The End (DNA PROTEIN SYNTHESIS ETC)) Flashcards
What makes a nucleic acid a nucleic acid
If it contains the elements carbon, hydrogen and oxygen , nitrogen and phosphorus too!
What do all nucleotides no matter what have
- A pentose monosaccharide (sugar)
- a phosphate group
- a nitrogenous base , containing one or two carbon rings with nitrogen
How do nucleotides join?
Where are these
What is it called
condensation reactions
- between the phosphate group of one nucleotide on the 5th carbon of the sugar
- and the hydroxyl group OH on the third carbon
= phosphodiester bonds , covalent and STRONG
What is the long chain of sugar and phosphate formed by phosphodiester rebounds called
How can break
This is the sugar phosphate backbone
Broken by hydrolysis reactions that require adding a water
What makes the end 3’ or 5’
Other strand?
- connecting nucleotides to each other, the first one will be the 5’ end as this is left (it’s the phosphate group attached to fifth carbon)
- the end will be 3’ as it is OH group left behind.
- This will be reversed on other side as they are ANTIPARALLEL
What specific for DNA structure?
- all pentose monosaccharide sugar = deoxyribose
- all have same phosphate group
- nitrogenous bases vary = Adenine thymine cytosine and guanine
Ribose vs deoxyribose ?
Both have the OH on carbon 3, fine, that lets the phosphodiester to happen
-Deoxyribose is a sugar WITHOUT oxygen on carbon 2, ribose does!
Which are pyrdimines and which are purines
Pyramidine = has a Y= so has to be cytosine and thymine
Thus Purine = what’s left = Adenine and guanine
What separates a purine from pyrimidine
Purine are bigger, have DOUBLE RING carbon structure
Pure = big maybe?
Pyrimidine have single ring
Why are AT and CG complementary to each other ?
How many bonds
A purine will bind with pyrimidine so AT and CG,
Complimentary be amuse they bind to form specific amount of hydrogen bonds, here
AT= 2
CG =3
How is the arrangement if nucleotide in DNA THEN
What does does being antiparallel mean
- First a Strand of a polynucleotide is formed through phosphodiester bonds
-Two strands of POLYNUCLEOTIDES held together by hydrogen bonds between nitrogen bases
= this gives a DOUBLE HELIX - The only way they can be arranged is if they run in oppsoite directions = ANTIPARALLEL
Why is the base pairing properties important
It allows for DNA to be copied perfectly and be transcribed
Describe the Structure of DNA briefly one more time
A double helix of two antiparallel strands of polynucleotides
Why does the fact base pairing is complimentary mean in terms of quantity if each base
It means adenine will always bind to thymine and cytosine always to guanine, thus there always will be equal amount of a to t and c and g !
What is an mRNA molecule
A short section of DNA that codes for a gene transcribed into a short RNA molecule called mRNA, still a polynucleotide
Structure of RNA
What’s different from DNA too
Pentose monosaccharide = RIBOSE (oxygen on carbon 2)
- phosphate group the same
- nitrogenous base= Adenine guanaine cytosine
and also URACIL instead of THYMINE
2) can only make ONE CHAIN NOT TWO of polynucleotide strand
Is uracil purine or pyrimidine and how many bonds formed with adenine (why complimentary still)
Replacing thymine, it is a pyrimidine , so single carbin ring
Makes two hydrogen bonds with adenine so STILL complimentary
How to extract DNA from plant in steps
Why
1) grind sample with mortar and pestle
- grinding will break down the cell walls
2) add dna extraction buffer which = detergent, salt and protease enzymes
- detergent breaks up cell membranes, releasing contents of the cell out
- salt breaks down hydrogen bonds between the DNA and the WATER MOLECULEs in solution
- protease enzymes break down peptide bonds of the HISTONE PROTEINS , allowing DNA to come out
3) filter mixture if needed
4) then add ice cold ethanol
- this allows the DNA to precipate out of the solution
- DNA no longer protected so ethanol can keep it protected
5) as it precipates , extract
Explain the DNA extraction process again (why do each step)
How can you improve with temp? Or RNAse
1) grinding allows for cell walls to be broken
2) detergent breaks up the cell membrane by dissolving them and thus disrupting structure of the phospholipids, which breaks them apart (like fats on dishes)
- salt breaks the hydrogen binds formed between dna molecules and the water . This causes the DNA TO CLUMP TOGETHER
- and protease enzymes break down histone proteins the dna is wound around, allowing them to no longer be compact anymore and releases them
3) ice cold ethanol forced dna to predicate whilst keeping protected as the dna is exposed now
4) extract it on a splint at an angel or the dna will get DAMAGED
1) heat it so cell stops working and all enzymes denature
2) you could add RNAse before protease to break down any RNA too
Why do cells require energy for + examples
3
Synthesis, transport, movement
Synthesis = large from small Transport = pumping molecules or ions across membranes by active transport Movement = protein fibres being contracted
What is the structure of an ATP nucleotide
- nitrogenous base which is always ADENINE (aden)
- pentose monosaccharide always ribose (osine)
- three phosphate groups (triphosphate)
Why is ATP Known as universal energy currency
This is because it is used for energy transfer in all cells of all living things , they all use ATP
Why are chains of ATP not made
What happens and why is this a good thing
Three phosphate groups are negatively charged so close will REPEL each other ,
- this makes it unstable, but useful, as the property of losing a phosphate group can be used
How does ATP release energy then overall
- unstable phosphate detaches as a bond between breaks.
- a little amount amount for energy is required for this
- but the energy released after when bonds are made in other reactions means overall MORE ENERGY IS RELEASED .
- thus you can say when bonds are “broken” energy is released here
