From the experiment with virulent, avirulent, & heat-killed virulent bacteria, they discovered that __. This is called the __
by adding heat-killed bacteria to avirulent bacteria, genetic material was passed on from a virulent to an avirulent bacteria. The presence of that gene (in this case, the thick capsule) causes the mouse to die;
evidence that DNA is the genetic material when pure DNA was isolated from the capsulated bacteria
- CapS (from isolated pure DNA) was found to be the gene responsible for generation of a capsule (makes it pathogenic). When CapS was entered into a non-pathogenic (non-capsulated) cell, recombination & cell division produces pathogenic, capsulated cells.
Crick referred to the pathway of info flow from DNA to RNA to protein as the __
- Central Dogma
Flow of the information was considered unidirectional. Information of protein cannot be used by cells to synthesize RNA. However, later on, it became clear that in especial cases information of RNA can be used to generate DNA.
The bacteria were grown in media containing heavy isotope of nitrogen (15N): DNA containing heavy isoptope, then switched to the regular media (14N) and harvested the cells after 1 or 2 generations. The DNA was isolated and density gradient centrifugation was performed. The DNA bands indicated that __
- with each generation, the DNA became lighter (less of the heavy isotope of nitrogen). There was only one band of DNA after the transfer to one regular media for one generation and 2 bands after 2 generations.
Enzymes that could transcribe RNA from DNA are called __
Enzymes need the presence of __ to polymerize RNA molecules.
- DNA and nucleotides ATP, UTP, GTP, CTP
__ was used as the template for transcription
- Only one strand of DNA
In the Pulse Chase assay experiment, RNA was found to be synthesized in the __ & moves to the __
- nucleus; cytoplasm
the entire genetic complement of a living organism that contains the biological info needed to construct and maintain a living example of that organism
- made of DNA in most organisms
- made of RNA in some viruses
base + sugar = __
- base + sugar + phosphate (1 or 2 or 3) = __
- nucleoside; nucleotide
Nucleotides are linked by __ bonds connecting the 3' of the sugar of one nucleotide to the 5' of the next nucleotide's sugar.
There is a __ in the structure of each strand, starting at __ and ending with the __ on the other end.
- 5' phosphate;
- 3' OH
In one strand of DNA, nucleotides can be arranged in __
any order (any nucleotide can follow the same or anyother nucleotide)
On one side of each glycosidic bond, the less open angle is __ & on the other side of it, it is __.
- ~120 degrees (the minor groove);
- ~240 degrees (the major groove)
- Major grooves are more important for interaction of proteins with DNA as they are wider (more room for interactions)
__ is the average conformation (of a double helix) seen in physiological conditions
- Depending on the sequence of DNA, the B-form may change to some extent affecting the major and minor grooves.
__ sometimes occur in DNA protein interactions & is more similar to RNA if it makes a double strand structure
__ is a left handed helix with a zigzag structure
This happens if the sequence is made of purine and pyrimidine alternates in a solution with high concentration of charged ions (Na+).
__ has the largest diameter & __ has the smallest diameter.
- A DNA (A-form); Z DNA
__ has the largest distance per complete turn & rise per base pair and __ has the smallest distance per complete turn & rise per base pair.
- Z DNA; A DNA (A-form)
- separating the 2 strands of DNA from each othercan happen by breaking hydrogen bonds by high temperature or high pH
The two strands can be attached with each other again (renaturation) if __. This reattachment is by restoration of __ and is known as __
The temperature or pH are brought down;hydrogen bonds;hybridization or annealing
(For this hybridization the sequences of both strands should be complementary.)
Absorption of UV light is done by the __
In the double strand DNA, due to the stack of bases that makes them unavailable to UV, the UV absorption is __ compared to 2 separate single strands of DNA (denatured DNA)
- 40% less
Increasing temperature will cause a rapid __ in absorption.
What factors increase the melting temp of DNA?
- higher G:C = more hydrogen bonds = higher melting point. Also in base pair stacks, G:C has more interaction with adjacent base pairs.
- ionic strengths: higher salt concentration = higher melting temp. High levels of positively charged ions surround the negatively charged phosphates in DNA backbone, therefore its is easier for both strands to not repel each other
What factors decrease the melting temp of DNA?
shorter DNA fragments = lower melting temp