DNA day 3 1B part 1 Flashcards
Nucleic Acids +ex(3)
consist of equal parts pentose sugar, Nitrogenous base, phosphate
made of long strands of nucleotides
Ex: DNA, RNA
2 types of sugars( each for what? )2)
ribose=RNA
Deoxyribose=DNA
monomer of nuleic acid
nucleotide
Difference between ribose and deoxyribose and what each have at the yk part (2)
the 5 carbon sugar in DNA is similar to RNA but DNA lacks a oxygen at the 2’ carbon
The two sugar only differ in the type of chemical group bound to the 2’ carbon. Hydroxl in ribose and hydrogen on deoxyribose
Nitrogenous bases in DNA
ACTG
Nitrogenous bases in RNA
ACGU
Purine +size/shape(2)
Adenine and Guanine
Double ringed
Pyrimidine+ size/shape (2)
Cytosine, Thymine, Uracil
single ring, smaller then purine
The DNA base that pairs with each other are not at cg
similar in shape/size
where does the sugar binds for purine?+ start counting N1 as
(3)
N9
at the NH
the one after the h2N group
where does the sugar binds for pyrimidine (2)
N1
NH
The difference between Thymine and Uracil
Thymine has an extra methyl group CH3 then Uracil
which base have nh2
Adenine, Guanine, Cytosine
Nucleosides
pentose sugar and base
Which base has double bond O?
Thymine, Guanine, Uracil, cytosine
everyone except adenine
deoxyribonucleosides(2)
deoxyribose sugar +purine/pyrimidine base
no phosphate
Where does the sugar and base bind?
So they connect… (2)
base binds to c1 of deoxyribose and ribose
Conmect at c1 of sugar and N9 purine base or N1 Pyrimidine base
Deoxycytidine is
deoxyribose pentose sugar+ cytosine
Adenisine is
+ interesting diff between it and deoxyadenosine
(2)
Adeisine+ ribose sugar
**extra O at the c2 area of sugar
Nucleotides are (2)
Nucleosides+phosphate
building block of DNA
How is Phosphate group attached to the ribose and deoxyribose of the sugar
Phosphate group is attached to the Carbon 5 of the sugar and the 3’ of the adjacent nucleotide
DNA (3)
basic unit etc
charge related (2)
A polymer of deoxyribonucleotides
polar molecule
Negatively charged due to phosphate in the backbone
So how does nucleotides connect in a strand? + act that bond(3)
via phosphodiester bonds (COPOC)
covalent bonds
The phosphodiester bond forms between the phosphate and the c3’ of one pentose sugar and the c5’ of the other
How many hydrogen bonds between AT?
2
How many hydrogen bonds between CG?
3
Chargaff’s Rule (4)
- %purines (Adenine+Guanine)=%pyrimidine (Cytosine+thymine)
- C+G =/ A+T
- ACGT are not present in equal amounts
- A=T C=G
Watson and Crick after stealing Rosalind’s work concluded that (4)
- The two strands of the phosphate -pentose backbone spiraled as a double helix about a common axis
- The two strands run antiparallel (one strand is in the 5’-3’ while the other is 3’-5’)
- A purine on one strand is always paired with a pyrimidine
- Backbone exterior is hydrophilic and the bases interior was hydrophobic
what keeps the base intact?
hydrogen bonding
5’ is identified by
phosphate group
3’ is identified by
hydroxl group OH
what is the diff btwn h bond and phosphodiester bonds USE KEY WORDS DA (2)
H bond keeps the two DNA strands tgt in a double helix
phosphodiester bond keeps the deoxyribonucleotide in a single strand
how to seperate the DNA strand? (2)
add a base/ akaline
heat it up
How to reform two DNA molecule tgt? (2) +whats the rule before it can come tgt? (1)
Cool slowly or add acid
It has to be complementary for it to reform
Complementary base pairings allows parental strands to act as
templates DNA replication of new strands
How do you unwind a parental strand?
By breaking the H bond
Semi conservative replication
The double helix contain a parental strand a newly synthesized strand
