Lesson 9: DNA Flashcards
where are genes carried and what form are they carried in
genes are carried on chromosomes in the form of DNA
how was DNA discovered
it was discovered by Friedrich Miescher in 1869, who isolated a compound found in the nucleus of a cell
what was the compound Friedrich found in the nucleus of the cell called
nuclein
how long did it take to determine that DNA was responsible for heredity
decades after Friedrich isolated this compound
who verified that genetic material was contained in the nucleus?
joachim hammerling verified this in the 1930s
- it was noted that in a single celled algae called Acetabularia, the cell would only regrow if the nucleus was still present
what did hammerling determine from his experiment with algae
he determined that the nucleus must contain the genetic material
who proved hammerling’s hypothesis? how did they do this
hammerling’s hypothesis was proven in 1952 by Alfred Hershey and Martha Chase
- they did so by showing that viruses only need to inject their DNA into a cell to take over their organelle to produce more virus, which proved that DNA was the hereditary material
- this is because when virus injects DNA, its instructions override the other instruction and instructs the cell to make more virus (genetic material AKA DNA was the hereditary material that gave instructions)
what is DNA chemically composed of and who was this discovered by
in the 1920s, Phoebus Levene discovered DNA had 3 main components
- a pentose sugar (5 carbon cyclical sugar)
- a phosphate group with a negative charge
- a nitrogenous base
what do the components of DNA come together to form?
a nucleotide, which are building blocks of DNA
What is DNA?
deoxyribonucleic acid; its a molecule or a bunch of atoms stuck together which combine to form the shape of a long spiraling ladder- it is a molecular blueprint for a living thing
what does DNA tell amino acids to do
how to line up and form themselves into protein shapes
DNA lives in… amino acids live in…
DNA= nucleus
amino acids= cytoplasm
whats RNA
like DNA but shorter and is missing one side
what is RNA able to do and how do they do it
RNA can go out the cytoplasm and into the ribosomes, which reads RNA codes and sticks them together in a chain which forms a perfect protein
explain the sequence ish of DNA, RNA, etc
DNA makes RNA which makes proteins which makes life or what not
what are the 4 possible nitrogenous bases that make up the nucleotides of DNA
- adenine (A)
- guanine (G)
- thymine (T)
- cytosine (C)
who discovered the key relationships between nitrogenous bases, and what are they
in 1940, erwin chargaff discovered the relationship between the bases
- the amount of adenine = amount of thymine
- amount of guanine = amount of cytosine
what did the discovery of the relationship of the bases help with
helped determine the structure of DNA
what did rosalind franklin do
while working with maurice wilkins, she discovered that the DNA molecules must have a helix or corkscrew shape
how did james franklin and francis crick determine the structure of DNA
they met with wilkins and saw the image that rosalind had taken- then they built a model and determined that DNA had the double helix shape
what did the model of the structure of DNA account for (what facts)?
- that DNA is made of a pentose sugar, a phosphate group, and nitrogenous bases
- the proportion of A-T and C-G is equal
- DNA has the shape of a helix
