Chapter 6 Flashcards
(64 cards)
Plasmids
Small extra chromosomal, double stranded, circular DNA molecules and it is found in the mitochondria. Prokaryotes and eukaryotes have it.
Fredrich Meicher
He was the first to identify DNA as a unique molecule in a cell in 1869
Robert Feulgen
He did a staining technique that stained more or less based on the amount of DNA present. He found that all cells had the same amount of DNA, except gametes which had half the amount in 1914
Fred Griffith
He mentioned that the bacteria in his experiment had transformative characteristics.
Griffiths experiment
Fred Griffith showed that the bacteria could be transformed from one strain to another by transferring genetic factor from one organism to another. Bacterial transformation- dead R-strained turned into S- strained living
Valent strain
Caused death
Avalent strain
Did not cause death
Avery, MacLeod, and Mc Carty
In their experiment they used various molecules such as RNA, protein, DNA, lipid, and carbohydrate that are found in the S- strain cells to prove that DNA was responsible for the transformation of the bacterial cells.
Experiment Chargaff
Nitrogenous bases were present about the same amount. One strand of DNA had 50% nitrogenous bases.
Rosalind Franklin
She used an x-ray crystallography to determine that DNA is double stranded, a helix, and that phosphates were on the outside and three distances which were, 2.0 nm, 0.34 nm, 3.4 nm showed up in a pattern constantly. These distances were between the nitrogenous bases and complete turn of a helix.
James Watson and Francis Crick
They used Chargaff’s and Franklins work in order to determine the structure of DNA by making models.
DNA replication
It happens at the same time in many locations along very long eukaryotic chromosomes. Replication bubbles are common.
Helicases
They are enzymes responsible for the unwinding of the DNA molecule in both directions. They form bubbles to release tension and break hydrogen bonds.
Topoisomerase I and II
They come in when there is tension in the DNA strand that causes it to tangle as it is unwound by the helicase. They are responsible for relieving that stress by clipping one or two strands of the DNA in front of the replication fork.
Nucleotides as triphosphates
Nucleotides are always added on as triphosphates. Once they are added then two phosphates are divided off making a pyrophosphate. DNA is always added to the 3-prime end of the growing strand not the parent template strand.
DNA polymerase
Is an enzyme responsible for the base pairing the correct nucleotides to the template. It creates the formation of hydrogen bonds. DNA synthesis (grows in length) happens only in the 3 -prime direction.
What are proteins useful for?
Carrying gases, Enzymes, structure, storage of protein, movement, and antibodies
The central dogma
Transcription and translation
Where does transcription occur?
In the nucleus
Where does translation occur?
In the cytoplasm
polynucleotide
A series of nucleotides linked together
Nucleotide contains 3 parts what are they?
A pentose sugar, nitrogenous base, and a phosphate group.
What are the three main types of RNA
mRNA, tRNA, rRNA
mRNA
Carries the information from the DNA gene to the cytoplasm. Determines the sequence of amino acids for a protein.