DNA Flashcards
Was Hooke’s observation on cell walls or living cells?
cell walls
what did Anthonie Van Leeuwenhoek call the living cells?
animalcules
who was the first person to identify the nucleus and what type of cells did he observe it in?
Anton Van Leeuwenhoak, salmon RBCs
Who made the link between the nucleus and cell division?
Shleiden
what did Shleiden call the nucleus?
cytoblast “cell builder”
What did Oscar Hertwig identify?
sperms transfers their nuclei to the oocyte
what was believed before Hertwig identification in regard to sperm?
sperms contained tiny human “homunculus”
who discovered the DNA?
Friedrich Miescher
Who was the first person to extract cell nuclei?
Friedrich Miescher
Why did the components of the nuclei tested positive in protein tests in Friedrich experiments?
DNA interacts closely with proteins
what was the name of deoxyribonucleic acid before it was renamed?
nuclein
What is the name of the dye that stains DNA and why was it important?
fuchsin, the discovery that all cells contain DNA
what was the identification of Griffith?
that there was a transforming factor that could make non-virulent bacteria virulent
what was the identification of Oswald Avery in regard to the transforming factor and what process did he use to make the identification?
The transforming factor was DNA
used a process of elimination (eliminating RNA and the protein)
What was the Phoebus Levene discovery?
he discovered that DNA is made of nucleic acids that consist of:
* nitrogen containing bases
* sugar molecule
* phosphate molecule
What is Chargraff’s rule?
There is always the same amount of:
* Adenine (A) as Thymine (T)
* Guanine (G) as Cytosine (C)
What was the idea of Levene that was debunked by Chargraff?
idea of an ordered repetitive sequence
What was the contribution of Rosalind Franklin and Raymond Gosling into the discovery of DNA’s structure?
that it was helical
What was the contribution of Maurice Wilkins into the discovery of DNA’s structure?
nucleotides of DNA had to be arranged with hydrogen bonds facing inward
Who discovered the overall structure of DNA using the information of from different scientists?
Watson and Crick
What are the benefits of knowing the structure of DNA?
- help explain how cells can replicate DNA
- help explain how DNA make transcripts of genes
- help explain how proteins bind to DNA for regulation
- helps explain the packaging of DNA in the nucleus
how long the human genome is?
2 m
So how does a 2 m long piece of DNA fit into a 5 µm nucleus?
wrap around itself in a highly ordered process so that genes used as necessary (chromatin)
How much shorter is the mitotic chromosome in comparison to it’s extended length?
10,000 times
what did Matthew Meselson and Franklin Stahl discovered?
DNA replicate using template strands that replicate a new duplicate strand (semiconservative model)
How was the semiconservative model proved?
DNA built with N( isotope 15) bases left to replicate in a medium with N( isotope 14) bases:
the proportion of N(15)-containing strands decreased with each replication (1, 0.5, 0.25, …) (DNA with N(15) fells down as it’s heavier)
who was the first to use the term gene?
Wilhelm Johannsen
What did Thomas Hunt Morgan claim?
genes lay in chromosomes (experiments on flies)
What is a gene?
is the genetic code that codes for an mRNA
What is the central dogma?
theory that states that genetic information flows only in one direction (DNA > RNA > Protein, or RNA > Protein) but not the other way around
What do genes express?
proteins (structural, signaling, enzyme, transcription factors)
What did Archibald Garrod formulate?
one gene, one enzyme hypothesis