Chapter 6 Flashcards
What did Frederick Meischer collect to find his discovery ?
Pus from bandages that contained (from white blood cells)
Why is it called the S-strain of pneumonia ? (smooth strain)
Capsule surrouding each cell and caused the bacterial colonies to looks smooth and glossy when grown
R-strain (rough strain)
When Frederick Griffth did his experiment with pneumonia the second culture of bacteria without the capsule formed irregular colonies.
Frederick Griffth mice, what occurred when he injected them with the S-strain and R-strain
S strain = [think suicide] The S-strain was pathogenic and when injected into the mice they died of pneumonia in a matter of days. However when heat-killed (dead) S-strain did not kill the mice.
R strain = [rescue] The R-strain of pneumonia did not kill the mice.] When heat killed S-strain combines with live R strain it kills the mice
What are the four outcomes of the mice from Frederick Griffith expermient?
1) They die (S strain)
2) They live (R strain)
3) Heat killed S strain they live
4) Heat killed S strain was alive again when with the R strain
He understood that hereditary substance had passed from dead S to live R, when R acquired the material they were transformed to infectious S.
Definition: Transformation
A change in a genotype or phenotype caused by the direct uptake of genetic material by a cell
The dudes
1) Frederick Meischer
2) Frederick Griffith
3) Oswald Avery
4) Colin McLeod
5) Maclyn McCarthy
6) Hershey
7) Chase
8) Phoebus Levene ( found the three major components of DNA)
9) Edward Chargaff (found the ratios of nitrogenous bases)
9) Rosalind Franklin (structure of DNA )
10) Maurice Wilkins (structure of DNA )
Definition: Bacteriophage
A virus that infects bacteria
A virus is NOT a living thing as it needs a host to survive. It inserts its genetic material into the bacteria (the host) and uses the bacterias cellular process to produce new bacteriophages.
What was the goal of Hershey and Chase
The bacteria men ! Hershey and Chase knew that viruses were able to transform bacteria but they did not know what did the transformation it was either the DNA or protein coat.
What was the experiment that found that DNA carried hereditary information. Who helped discover it?
The experiment was designed by Hershey and Chase and was similar to using S and R strains. Instead they used the radioisotopes of sulfur for proteins and phosphurus for DNA. They labelled bacteriophages and infected different colonies. The bacteria that were radioactive was the one labelled with phosphrus therefore DNA carried the genetic material.
What are the three major components of DNA ?
Deoxyribose sugar, phosphate group, and nitrogenous base
DNA is polymer made up of nucleotide subunits. Each subunit contains a NB connected to a Deoxy sugar and connected to phosphate group.
Definition: purine
A class of nitrogenous bases with a double -ring structure
(A) denine and G(uanine)
Definiton: pyrimidine
Single ring structure
(T)hymine
(C) ytosine
What technology did Wilkins and Franklin use to discover the structure of DNA?
X-ray crystallography. X -rays are shot at a solid compound that deflects in a certain way creating a pattern on a photographic plate.
What did Franklin discover about the structure of DNA {yes woman in STEM}
Franklins crystallography suggested that the sugar-phosphate backbone of DNA faced the outside and that DNA was a double helix that rotated clockwise.
Diameter of DNA 2nm
On turn of a helix was 3.4nm
What are the percentages of the nitrogenous bases ?
30.9% A, 29.4% T, 19.9% G, and 19.8% C
What did Watson and Crick discover?
Showed that DNA can be stable if each strand ran antiparallel from each other. DNA strand must have the hydroxyl of the 3’carbon attached to the deoxyribose sugar at one end of the phosphate attached to the 5’ carbon of the last sugar. And then vice versa to achieve antiparallel. Also that the purine and pyrimidine base pairs link to each other.
Definition: Complementary base pairing
The chemical tendency of adenine to form hydrogen bonds with thymine, and C to form hydrogen bonds with G
How did symmetry play an in important role in DNA?
The symmetry of DNA gives it the ability to divide itself accurately and convey genetic information
What does deoxyribonucleic acid ensure?
- That genetic information is passed on from one generation to the next ( in the form of chromosomes)
-Build the required proteins for life
What do chromosomes do in eukaryotes?
Chromosome passes on information for organism’s construction and operations. Size and number of chromosome is specific to each species- occurs in homologous pairs. Most eukaryotes are diploid (2 sets of chromosomes)
Example: In humans our genome consists of 23 pairs of homologous chromosomes
