Chapter 6 Flashcards
(36 cards)
DNA
Deoxyribonucelic Acid
Nucelotides
Composed of three components:
- Deoxyrbose sugar
- Phophate group
- One of the four nitrogenous base
Bonds joining one nucleotide to another
Phosphodiester bonds
Polymer
Linked chain of building block subunits
Ability of a substance to change the genetic characteristics of an organism
Transformation
Bacteriophages
-“phages”
Viruses used to infect bacterial cells
polarity
an overall direction
What was Frederick Griffith’s experiment?
worked with two types of S.penumoniae bacteria- live R fooms and heat killed S forms but neither killed the rats He then added a mixture of the two into the mouse and it killed him. He discovered what is now called transformation
Transformation
the ability of a substance to change the genetic characteristics of an organism
What was Oswald T. Avery’s contribution to the study of hereditary?
Avery found that they could achieve transformation without using any animals at all simply by growing R-form bacteria is medium in the presence of components form the dead S form. Found the transforming principle to be DNA
bacteriophages
bacterial cells with viruses
What was Hershey and Chase’s experiment? What did it verify?
- felt they could assess the relative importance of DNA protein in gene replication
- grew two separate sets of T2 in bacteria maintained in two different culture media, one infected with radioactively labeled phosphorus and the other with radioactively labeled sulfur
- found that DNA was the genetic material
What are the components of nucleotides?
Consists of deoxyribose sugar, a phosphate and one of the four nitrogenous bases
Nucleoside
covalent attachment of a base to the 1’ carbon of deoxyribose
nucleotide
the addition of a base to the 5’ carbon
Who produced the x-ray images of the shape of DNA?
Rosalind Franklin and Maurice Wilkins
-showed that the molecule is spiral-shaped or helical
B form DNA
DNA that spirals to the right
Z form
helix spirals to the left and the backbone takes on a zig-zag shape
What shapes do eukaryotic chromosomes come in?
linear double-helixes and circular
template
molecular mold used for synthesis of a second strand of DNA
semi-conservative replication
copying in which one strand of each new double helix is conserved from the parent molecule and the other is newly synthesized
Both daughter double helixes would carry blocks of original DNA interspersed with blocks of newly synthesized material
dispersive replication
Who confirmed the semi-conservative nature of DNA replication?
Matthew Meselson and Franklin Stahl
-used isotope 15N and 14N
What direction does DNA polymerase move along the template?
3’ to 5’ direction
