Bio 12 Flashcards
Fredrick Griffith
The first scientist to discover transformation, he was originally looking to create a vaccine for pneumonia
Oswald Avery
Fredrick griffiths student who first discovered that DNA was responsible for the transformation
What were the strains of bacteria that griffith discovered and what did the look like?
The smooth(s) strand caused pneumonia to occur because the mouse couldn’t penetrate the smooth coating
The rough (r) strand didn’t cause pneumonia because the bacteria
What did Griffith do to the smooth bacteria that caused them to not cause pneumonia
He heat killed them, and it worked!
-this showed that the bacteria wasn’t a poison, it needed to be alive to attack the cells
What did Griffith do to the rough bacteria to make them cause pneumonia
He mixes them with the neat killed smooth bacteria. The mice die from pneumonia and in their lungs are the SMOOTH bacteria
Through all of Griffiths experiments, what does he find?
Genetic material from heat killed bacteria and the rough bacteria combined causing a smooth pneumonia causing bacteria- THIS WAS CALLED TRANSFORMATION
What was Avery’s research
Avery continued Griffiths research, he used enzymes to show that when DNA was destroyed, the pneumonia never happened
Alfred Hershey and Marta Chase
They experimented with bacteriophages and using radioactive markers determined that DNA was transferred from bacteriophages to cells.
Which scientist’s expiriments showed that DNA (not protein) holds genetic material?
Avery, and Hershey and Chase
What is the structure of DNA and what is it made of?
-double helix
- 5 carbon sugar, phosphate group, one of four nitrogen bases
What are the 4 nitrogen bases in DNA?
How do they change in RNA?
DNA: RNA:
Adenine - Adenine
Guanine- Guanine
Cytosine- Cytosine
Thymine- URACIL
What are the base pairing rules and who determined them?
In a DNA molecule the amount of Adenine = Thymine, and Guanine = Thymine, they are always paired together with hydrogen bonds.
ERWIN CHARGAFF
How many hydrogen bonds are between Adenine and Thymine?
How many for Guanine and Cytosine?
Adenine& Thymine- 2 hydrogen bonds
Guanine and Cytosine- 3 hydrogen bonds
What class are Adenine and Guanine?
What class are Thymine and Cytosine?
Adenine& Guanine- Purine- Double rings
Thymine & Cytosine- Pyrimidine- One ring
What is transformation?
When (in Griffiths experiments) one bacteria’s DNA transformed into another’s
nucleotide
Monomer of DNA-
- 5-carbon sugar
- phosphate group
- 1 of 4 nitrogen bases
Wilkins and Franklin
Two researchers who worked for years determining DNA’s structure
Watson and Crick
Two ‘researchers’ who stole and published (and got all of the fame for) Wilkins and Franklin’s research.
How much DNA is in a single cell?
How can it be stored?
Around 100,000 times the length of the cell or about 6 feet.
It is wound tightly around histone proteins and itself
What are the layers of how DNA is wrapped?
-wound around histone proteins- nucleosomes
-compacted tightly- chromatin
- wound even more (sometimes)- chromosomes
DNA replication
A process occurring during the S-phase of cell division, DNA splits and one strand is able to code for the other.
What are the steps of DNA replication
- DNA helicases break apart the helix shape forming Replication Forks or bubbles
- DNA polymerases move along the single strands of DNA and add nitrogen bases (that are complimentary to the DNA) together
- DNA polymerase detaches
histone proteins
proteins that RNA strands wrap around forming nuclosomes
What is a common enzyme that helps in DNA replication and proofreads
DNA polymerase
How does DNA replication differ between pro and Eukaryotic cellse?
pro- JUST ONE replication fork
eu- Hundreds of replication forks, can finish in one hour
Why is DNA replication possible with only one strand of DNA?
DNA’s bases are complementary- chargaffs base pairing rules
What are the three main types of RNA used in protein synthesis
What do each of them do?
mRNA- messenger RNA- Codes for proteins using genes from proteins
tRNA- transfer RNA- In chunks of anti codons that each hold an amino acid at the top- help to line up amino acids
rRNA- ribosomal RNA- Help make up the structure of ribosomes which help mRNA build Proteins
RNA vs. DNA
Uracil vs. Thymine
ribose vs. deoxyribose
double vs. single stranded
What is RNA? How is it formed?
RNA is the disposable version of DNA, it often codes for proteins directly
It is formed through TRANSCRIPTION
transcription
The process of DNA coding for RNA
1. DNA Splits
2. RNA polymerase builds RNA using info from DNA
3. this forms PRE- mRNA
pre- mRNA is made on introns and exons
intron vs. exon
introns are parts of DNA/ pre-mRNA that don’t code for proteins and are taken out during RNA editing, exons are left and are stitched together
Codon
one ‘word’ in a gene’s sentence. Three base pairs that code for a amino acid
anti codon
the complementary bases to a codon, found on the end of a tRNA with the corresponding amino acid on top
codon: anti-codon:
AGA UCU
What is the process of mRNA coding for proteins called?
TRANSLATION
- occurs on ribosomes
Describe the steps of translation
- final mRNA leaves nucleus through nuclear pores and lands on a ribosome
- tRNA (complementary to codon on mRNA) lands on mRNA in the P site
- the next tRNA lands next to it on the A site and amino acids bond
- the tRNAs shift over and a new one comes over and lands on the A site
-REPEAT-
what codon can speciffy “start” or “stop”
AUG
Mutation
change to genetic material
- can be a gene mutation (effecting one gene) or a chromosome mutation effecting entire chromosome
point mutation
a mutation effecting a single point:
- can be: deletion, duplication, translocation, inversion
frameshift mutation
a mutation that effects many codons because a base was added or deleted and the whole count by threes shifts:
THE CAT ATE
TtH ECA TAT E
What is the significance of a mutation?
most are neutral, the outcome stays the same
some can be bad or good
why does transcription need to be regulated
transcription only needs to occur for genes that are needed for the gene to be succesfful
are prokaryotic regulators more or less complex than eukaryotic regulators
less complex.
What did scientists know about genetic information before discovering DNA
- It needed to be passed on
- It needed to be copied
- It needed to store genetic information
Operon
Region on a prokaryotic DNA with the promoter, operator, and repressor for a gene
TATA box
region in the promoter of a eukaryotic cells that helps to position the RNA poymerase on the promoter
bacteriophage
virus that effects bacteria, studied by Hershey and Chase
replication
DNA replication, when DNA is split and replicated
- the different places it is split at are replication forks
Differentiation
When cells get different structures depending on they’re placement. This is determined by hox genes.
hox genes
genes determining the structure of a cell
enhancer sequences
sequences where proteins can bind to, then the RNA polymerase is either attracted to the proteins or stopped by them
Repressor
a molecule that binds to the operator on genes that stops the RNA polymerase from transcribing.
