L30 Flashcards
what is Griffith conclusion ?
Some heat sensitive substance in the heat-killed pathogenic S strain which transformed the ‘R’ strain to ‘S’ pathogenic strain
• This substance was called as “transforming factor”
• However, the transforming factor was not identified
what is Avery conclusion ?
Transformation could be due to protein • Therefore, it required further confirmation to
establish that DNA is genetic material
WHAT does Hershey and Chase use in their experiment ?
they use bacteriophage
radioactive phosphate is for ?
DNA
radioactive sulfur is for ?
protein
what is Hershery and chase experiment steps ?
1-radioactive label [ phosphate for DNA and sulfur for protein]
2- infection [ they infect bacteriophage inside the bacteria ]
3-blend to detach virus [مزيج لفصل الفيروس عن البكتريا عشان ما يكون لازق فيه ]
4- Centrifuge to separate virus from bacteria
5-Measure radio label
الفيروس كثافته اقل فيكون فوق والبكتريا تكون تحت بالpellet ويشوفون بما انه الDNA تتحت فاكبد it the genetic material
what is Hershey & Chase: summary & conclusions?
32P labeled DNA was detected inside the cells
• While the 32S protein was detected outside the cells
• The P32 labeled DNA has complete information to replicate and form the viral progeny
• DNA is the genetic material
what is the building blocks of DNA ?
nucleotides
true or false
there are 3 type of nucleotides in DNA
false
there are 4 type
what is the Building blocks of nucleotides ? 3 component
Nitrogenous bases + Pentose sugar +phosphate
they contain just five elements [ C ,H,O,N,P]
Adenine and Guanine are purines or pyrimidines ?
purines
pyrimidines are Cytosine and Thymidine
Four nucleotides collectively called as?
deoxynucleotide triphosphate (dNTPs)
what is the difference between nucleotide and nucleoside?
necleotide has three 3 components
nucleoside have inly 2 they are like nucleotide bet without phosphate group
what is the difference between purine and pyrimidine ?
There are two purines: Adenine (A) & Guanine (G)
• A purine has a double ring structure
- There are two pyrimidines: Thymine (T) & Cytosine (C)
- A pyrimidine has a single ring
instead of thymine RNA has ?
Uracil [U]
1C in Deoxyribose sugar attach to a base by ?
glycosidic bond
2C in DNA has OH or H ?
only H in DNA
in RNA in 2C it attach to OH
true or false
3C is attach to OH in both DNA and RNA
TRUE
X’C is attached to a ‘P’ group
what is X ?
5C
3’ -OH & 5’ P in different nucleotides form?
phosphodiester bond
Deoxynucleotide triphosphate (dNTP) serves as ?
serves as the substrate for DNA synthesis
DNA backbone is made of X connected by Y
what are X and Y ?
X= sugar phosphate Y= phosphodester bond [ 3'OH and 5'P ]
• A base is connected to the pentose [ sugar] by ?
glycosidic bond
true or false
There is no bonding between the adjacent bases
• A DNA strand has two ends: 3’ end- carries a free -OH group 5’ end- carries a free P group
• DNA is written and synthesized
in 5’ 3’ direction
true
true or false
DNA has 2 strands and parallel ?
false
DNA has 2 strands and antiparallel
the 2 strands of DNA are ?
The two strands are complementary: A = T by two H-bonds C = G by three H-bonds
• This is called base pairing rule given by E Chargaff
• Both strands are stabilized by
H-bonds
what is the 3 function of DNA ?
Storage of genetic information[حفظ, • Maintaining integrity of genetic information (repair)اصلاح
• Transmission of genetic information نقل
A model that explains these functions of DNA was proposed by Watson & Crick known as?
Watson and Crick model of DNA
Rosalind Franklin & Maurice Wilkins studied DNA structure using WHAT
in 1951?
X-ray crystallography
in 1950: E. Chargaff discovered?
base pairing rule
Bases being hydrophobic are located inside the?
inside the helix
IMP info
bases are buried inside
the helix is stabilized by H bond
;)
