Nucleotides And Nucleic Acids Flashcards
Draw the structure of a nucleotide
What are three parts of a nucleotide
Pentose sugar
Nitrogenous base
Phosphate group
What are nucleotides used to make
DNA and rna
Dna-used to store genetic info
Rna-used to make proteins from the instructions of dna
What’s the Pentose sugar in dna and rna
Dna-deoxyribose
Rna-ribose
In a dna nucleotide what could the bases be and in a rna nucleotide what could the bases be
Adenine,thymine,guanine,cytosine
Adenine,uracil,guanine,cytosine
How many polynucleotide chains do rna and dna have
Dna has a two polynucleotide chains
Rna has single polynucleotide chain
Explain how polynucleotide strands are formed and broken down
Condensation reactions between nucleotides form string phosphodiester bonds ( sugar phosphate backbone). Hydrolysis reactions use a molecule of water to break these bonds
Enzymes catalyse these reactions
What’s the purine bases and describe their structure
Adenine c5h5n5
Guanine c5h5n5O
Two carbon nitrogen rings joined together
What’s the Pyramidine bases and describe their structure
Thymine
Cytosine
Uracil
One carbon nitrogen ring
Pyramidine smaler than a purine base
Complementary base pairs in RNA AND DNA and how many hydrogen bonds between them
in dna- T and A and 2 hydrogen bonds
In rna - U and A and 2 hydrogen bonds
They both have C and G with 3 hydrogen bonds between them
What does the double helix looks like before it’s twisted
Two polynucleotide strands that are anti parallel running in opposite directions
How to purify dna
1)break up cells in sample using a blender for eg
2)make up a solution of detergent,salt and distilled water
3)add broken up cells to a beaker with the detergent solution
4)incubate beaker in water bath at 60* for 15 mins.( detergent in mixture breaks down the membranes at this point,the salt binds to DNA and causes it to clump together. Temp high enough to stop enzymes in cells from working properly and breaking down DNA)
5 ) AFTER incubated put beaker in an ice bath to cool down mixture
6)once it’s cooled filter mixture w filter paper and funnel and transfer a sample of your filtered mixture to a clean boiling tube and discard contents of filter paper
7)add protease enzymes to mixture (these will break down the proteins bound to the dna in mixture)
8)slowly dribble cold ethanol down the side of tube so it forms a layer on top of dna detergent mixture
8)leave tube for a few mins and a stringy white DNA precipitate will form which can be removed using a glass rod
Why does dna replicate?
It copies itself before cell division so each new cell has the full amount of dna. Important for making new cells and for genetic info from gen to gen
When does dna replication occur
During S phase in cell cycle
How is dna replicated
1) dna helicase enzyme breaks down the hydrogen bonds between the two polynucleotide strands so dna unzips to form two nucleotide strands
2)each original strand acts as a template for a new strand so the free nucleotides bind to the template strand with complementary base pairing.(atcg) Hydrogen bonds form between exposed based on template strands and free nucleotides.
3)nucleotides on new strand are joined together by DNA polymerase as it seals the sugar phosphate backbone and binds to the 3’ end of template strands.
4)It catalyses the formation of phosphodiester bonds between phosphate group and deoxyribose sugars of adjacent molecules forming a polynucleotide chain 5’ to 3’direction.
5)Dna ligase seals gap in the sugar phosphate backbone between Ozaki fragments on the lagging strand to form a continuous strand.
6) identical daughter strands are made through semi conservative replication as 1 original strand is kept in each daughter strand.
Why does dna replication have to be accurate
To make sure genetic information is conserved, each time DNA in a cell is replicated.
what’s the effect of mutations
They alter the sequence of amino acids In a protein. This causes an abnormal protein to be procured. This abnormal protein could be better than original protein or worse
What is inorganic ions
An ion w an electric charge that doesn’t contain carbon
What are the cations
Ca2+-involved in transmission of nerve impulses and the release of insulin
from pancreas and acts a cofactor for many enzymes.important in bone formation
Na+-important for generating nerve impulses for muscle contraction and for regulating fluid balance in the body
K+-important for generating nerve impulses for muscle contraction and for regulating fluid balance in the body. It activates essential enzymes need for photosynthesis
H+-affects Ph of substance(more H+ than OH- =acid) also needed for photosynthesis reactions that occur in thylakoid membranes inside chloroplasts and respiration reactions that occur in inner membrane of mitochondria
NH4+-absorbed from soil plants and important source of nitrogen =used to make amino acids and nucleic acids
What are the anions
NO3- absorbed from soil by plants and important source of nitrogen -used to make..
HCO3- acts as a buffer which helps to maintain PH of blood
Cl- involved in chloride shift which helps maintain Ph of blood during gas exchange. Acts as a cofactor for amylase.involved in nerve impulses too
PO43- -involved in photosynthesis and respiration . Needed for synthesis of many biological molecules like nucleotides (and atp) phospholipids and calcium phopshate(strengthens bones)
OH- -affects PH of substances ( more oh creates an alkali)
Compare rna and dna
DNA has double stranded and RNA has single strand
DNA found in nucleus and RNA found in ribsomes
DNA bases are ATCG and rna bases are AUCG
DNA has a deoxyribose sugar and RNA has a ribose sugar
Rna’s C2 is bonded to an o and dnas C2 isn’t
Both have phosphate group
Both have phopshodiester bonds
What materials are needed for dna replication
DNA polymerase enzyme,helicase enzyme,ligase enzymes
Free nucleotides(actg)
Intact dna-this is because both strands act as a template for replication
Energy source(atp) to phosphorylase nucleotides which activates them
Function of dna helicase
Unwinds the dna by braking the hydrogen bonds between complementary base pairs on the two strands of dna
Function of dna ligase
DNA ligase catalyses condensation reactions between the new nucleotides to create a polynucleotide chain.
