Molecular Structure of DNA & RNA Flashcards
Molecular Genetics
The study of DNA structure & its function at the molecular level
What are the 4 criteria genetic material must meet?
- Information
- Transmission
- Replication
- Variation
Information
Genetic material must contain the information necessary to construct an entire organism
Transmission
During reproduction the genetic material must be passed from parents to offsprings
Replication
Must be copied
__________________ contain both DNA & Proteins
Chromosomes
____________ experiments indicated that genetic material can transform pneumococus
Griffths
Describe Griffth experiment
He had two strains: a R strain which had no capsule & a S strain which has a capsule
When he injected the live R strain into the mouse it lived but when he injected live S strain into the mouse it died (This showed that the capusle is protecting the S strain from antibodies to cause infection)
He then injected a heat killed S strain (dead S strain) & a live R strain into the mouse & it died
What does the results of Griffths tell you?
Since when he adds the dead S strain & a Live R strain this shows us that the R strain took genetic material from the dead S strain & transformed into a S strain with its own capsule (process called transformation)
Transformation
When a bacteria dies & transfers its genetic material to another bacteria slowly modifying that bacteria
Avery, MacLead, & McCarthy showed that _______ is the substance that transforms bacteria to another bacteria
DNA
Describe Avery, MacLead, & McCarthy experiment
They purified macromolecules (lipids, carbohydrates, proteins, & nucleic Acids (DNA & RNA))
They realized when an R strain had DNA of S strain then the R strain turned into an S strain (So DNA is the genetic material & not proteins)
Hershey & Chase provided evidence that ______ is the genetic material of T2 phage (type of bacteriophage)
DNA
Bacteriophage (phage)
A virus that infects bacteria cells (has only 2 macromolecules (DNA & proteins))
Describe Hershey & Chase experiment
They labeled 32P for DNA (beacuse DNA have alot of P) & 35S for proteins
They grew infected cells in isotopes and a virus would either get 32P or 35S and they would inject new cells with one of the viruses
They realized that mostly DNA was inside the infected cell
Nucleic Acids
DNA & RNA
__________ & _________ are macromolecules & have 4 levels to their structure
DNA & RNA
What are the 4 levels to DNA & RNA structure?
- Has nucleotides
- Nucleotides are linked together in a linear manner to form a strand of DNA or RNA
- Two strands of DNA (sometimes RNA) interact with other to form a double helix
- 3D structure of DNA is found within chromosomes
_____________ is monomer made up of 3 things
Nucleotide
What are the 3 things that nucleotides are made of?
- Phosphate
- Sugar
- Base
What are the types of sugar?
- Dexoyribose (Found in DNA)
- Ribose (Found in RNA)
What are the two cateogories bases?
- Purines Bases
- Pyrimidine Bases
Purines Bases
Adenine (A), Guanine (G) (Have a double ring structure)
Pyrimidine Bases
Thymine (T), Cytosine (C), & Uracil (U) (Have a single ring structure)
_____________ only found in DNA & _________ only found in RNA it replaces thyamine
Thyamine & Uracil
Adenine, guanine, & cytosine found in both _______ & ________
DNA & RNA
______________ bond links the nucleotides in DNA & RNA
Phosphodiester
The __________ & _________ molecules form a “backbone” of the strand where it is negatively charged & the bases point inwards
Phosphate & Sugar
DNA is directional “polarity” where it runs in the ____ to ____ direction for one strand & the other strand runs in the ____ to ____ direction
5’ to 3’ or 3’ to 5’
Linus Pauling
Proposed DNA is in a helical strcuture
Rosalind Franklin & Maurice Wilkins used __________ to try find the structure of DNA
X- ray diffraction
_______________ found that DNA has a biochemical composition in which the amounts of adenine (A) & thyamine (T) are equal where they bind together & the amount of G & C are equal & they bind together
Charagaff
A binds to T in a _______ ratio & G binds to C in a 1:1 ratio
1:1
__________ & ___________ proposed the correct structure of DNA has a double helix
Watson & Crick
Describe Watson & Crick model of DNA
Showed that DNA has 2 strands in a double helix where there are hydrogen bonds between the bases
The backbone of DNA was on the outside & the bases were on the inside (stack like plates)
The two backbone strands where antiparrel so one strand is in the 5’ to 3’ direction & the other strand is antiparrel & in the 3’ to 5’ direction (twist helix)
A & T has ____ hydrogen bonds & G & C has _____ hydrogen bonds
2, 3
