The Genetic Code Flashcards
What is the genetic code referring to?
- The code tells the cell what proteins to make
What is Epistasis?
The effect of gene mutation is dependent on the presence or absence of mutations in one or more other genes
What was Beadle and Tatum’s theory on finding mutations, and why was it false?
- They argued that if genes make enzymes, then you should be able to find a mutant corresponding to every enzyme in the pathway
- BUT if allele does not produce a functional enzyme, then the pathway will not create another protein, and it will not grow.
What is an auxotroph?
- it is a microorganism with a mutation preventing it from producing a compound needed for growth
What is a prototroph?
- it is a wild type of microorganism, capable of producing whatever it needs for growth
Where are proteins made?
- In cytoplasm w/ help of ribosomes
What are 2 major differences between RNA and DNA
- RNA has uracil instead of thymine
- RNA has 2’ hydroxyl that DNA is missing
How does information get from DNA to RNA? What is this process called?
- This process is called transcription
- RNA polymerase “sits” on DNA and unwinds it to start creating RNA strand
- This creates mRNA
Describe the relationship between DNA sequence and amino acid sequence, does one determine the other?
DNA sequence determines amino acid sequence, but amino acid sequences does not determine DNA sequence
How does mRNA create amino acid?
- Once mRNA travels to the cytoplasm, it is attached to a ribosome (small unit)
- the big unit then attaches on with a start tRNA codon at P site (first site in larger unit)
- tRNA corresponds to next codon binds to A site, then moves to P site
How can the steps in information flow vary?
- many ribosomes can translate a single mRNA
- ribosomes sometimes begin translation before being done transcription (prokaryotes)
- proteins somethings begin function before translation is finished
What is a mutagen?
- A mutagen is any agent that causes mutation (virus, radiation, chemicals…)
