FINAL TERM Flashcards
They proposed the chromosomal theory of
inheritance(1902-1903).
Walter Sutton and Theodor Boveri
The chromatids get connected with each other at points
known as
Chiasmata
DNA itself was identified by Swiss chemist
Friedrich Miescher
molecule is slightly acidic, high percentage of
phosphorous, later he called it
nuclein
three major components of a single nucleotide
(phosphate-sugar-base)
Phoebus Levene
(other DNA molecule) nucleotide composition
of DNA varies among species, Chargaff’s rule
Erwin Chargaff
double stranded DNA, Nature in April 1953
1962: Nobel Prize in Physiology and Medicine
James Watson and Francis Crick (1950)
They disproved the notion that proteins were genetic material.
Griffith, Avery, Hershey, and Chase
Something from the dead type S bacteria was transforming the type R bacteria and S. Griffith called this process
Transformation
They Showed that DNA Is the Substance That Transforms Bacteria
Avery, MacLeod, and MacCarty
They Provided Evidence That DNA Is the Genetic Material of T2 Phage
Hershey and Chase
DNA “Saga” began when Swiss
biochemist Miescher isolated Nuclein
1868
Levene - Tetranucleotide Hypothesis
1910
Griffith - Transforming Principle
1928
Avery, MacLeod & McCarty - DNA is Transforming Principle
1944
Chargaff’s Rules - A=T, G=C
1950
Hershey & Chase - Blender Experiment
1952
Watson & Crick - A Structure for DNA
1953
➢King’s College, London
➢Initially a nuclear physicist
➢1950: X-ray diffraction work on ram
sperm and DNA from
➢With grad student Raymond Gosling
produced x-ray
➢photographs of DNA showing
crystalline structure
➢These photographs, shown at a
conference in Naples,
➢sparked James Watson’s interest in
DNA
Maurice Wilkins
“We realized that if DNA was
the gene material, then we
had just shown that genes
could crystalize…”
Raymond Gosling
English physical chemist and x-ray crystallographer expert
● Previously worked on x-ray diffraction patterns in coal and carbon fiber technology in Paris
Rosalind Franklin
Discovered 2 forms of DNA: A form (dehydrated) and B form (hydrated)
Rosalind Franklin
He solved basic mathematics of helical diffraction theory and proposed Wilkin’s x-ray diffraction data indicates a helical structure of DNA
Alec Stokes
Taken by Raymond Gosling in March 1952 under Franklin’s instruction
Photograph 51
American chemist, biochemist, peace activist
● Contributions to science include discovery of alpha helix
and beta sheet structure of proteins, quantum chemistry
resonance work and the discovery of sickle cell anemia as
a molecular disease
● “The Nature of the Chemical Bond”
● Considered to be one of the 20 greatest scientists of all
Time.
Linus Pauling
On what year Linus Pauling announced that he had discovered the structure of DNA
Early 1953
Photograph of the double helix was shown to
Watson by
Wilkins
Pioneered the paper chromatography of nucleic acids, using this to determine how much of each of the component nucleotides were contained in a DNA sample. He rapidly demolished Levene’s tetranucleotide hypothesis to discover his rule on ratios
Erwin Chargaff
He pointed out that the way the bases in these pairs would attach to their sugars meant that the two backbones ran in opposite directions
Crick
Who took the definitive picture of
DNA using x-rays?
Rosalind Franklin
The name given to the shape of DNA is?
Double helix
Which scientists built a 3-D model of the
DNA double helix?
Watson and Crick
Before a cell divides, it duplicates its DNA
in a copying process called
Replication
chromosomes are made up of thousands of
shorter segments of DNA, called
Genes
serves as universal
information-storage molecule
for all forms of life.
DNA
is a cyclical molecule.
➢ fifth carbon atom is
attached to the fourth
carbon of the ring
➢ hydroxyl group (-OH)
attached to the third carbon
in the ring.
Deoxyribose
is a phosphorous atom with four oxygen atoms bonded to it.
Phosphate group
It connects the 5’ carbon of one nucleotide to the 3’ carbon of another nucleotide
Phosphodiester bonds
nucleotides forming each DNA strand are connected
by
Hydrogen bonds
DNA polymers direct the production of other polymers
called
Proteins
Each gene is further divided into three nucleotide
subsegments called
Codons
the amount of protein produced by X-linked genes and randomly inactivated in two sexes
Dosage compensation
DNA replication is
semiconservative
➢Replication always starts at
specific locations on the
DNA, which are
called
origins of replication
➢two Y-shaped structures
called __________ forming _________.
replication
forks , replication
bubble.
What are the enzymes involved in DNA replication?
Helicase
Single-strand binding protein
TopoIsomerase
Primase
DNA pol III
DNA pol I
DNA ligase
Single strand
➢ Composed of:
➢Sugar (ribose)
➢Phosphate
➢Phosphodiester linkage
➢Nitrogenous bases:
➢A,G,U,C
RNA
What are the stages of RNA synthesis/ transcription?
Initiation stage
Elongation stage
Termination stage
Protein coding regions
Exons
Protein non-coding regions
Introns
- Small ribosomal unit attached to the start
codon of mRNA. - Amino acid brought by specific tRNA
- tRNA anticodon will complement with the
mRNA codon. - Attachment of the large ribosomal unit
(with A, P, and E sites) completing the
translation complex.
Initiation stage
-Large ribosomal subunit:
A site (Aminoacyl tRNA binding site)-
receiving the incoming amino acid.
Protein synthesis/ Translation
P site (Peptidyl tRNA binding site)- where the
peptide bond between amino acid
formed
E site- exit site of uncharged tRNA.
Elongation process
-elongation stops when it reaches the stop
codons (UGA, UAG, UAA).
Termination stage
