Exam 2 Flashcards
Describe all steps of DNA replication from beginning to end
1.) topisomerace will relax the supercoils of DNA
2.) helicase enzyme unzips DNA strand by breaking H bonds
3.) primase enzyme inserts a start marker on each strand
4.) DNA polymerase enzyme attaches to start marker and lays down new nucleotides in 5’ to 3‘ direction.
5.) leading strand is made in one continuous piece
6.) lagging strand is made in small segments called Okazaki fragments.
7.) lipase enzyme joins fragments together
8.) DNA polymerase corrects any errors in replication
Where does transcription happen in a eukaryotic cell?
Nucleus
Describe the process of transcription from beginning to end
1) certain enzymes will open up the DNA strand to create a transcription bubble
2) RNA polymerase enzyme will combine with transcription factors to form an initiation complex
3) The initiation complex will bind to the TATA box region of the template DNA
4) RNA polymerase splits from the complex and lays down new nucleotides in 5’ to 3’ direction
5) when the enzyme reaches the end of the gene, the newly made RNA splits away from the DNA
List 3 post-transcriptional modifications made to RNA
RNA splicing
Addition of a 5’ cap
Addition of a poly (A) tail
Describe all steps of translation from beginning to end
- The 5’ cap of mRNA binds to the small subunit
- The ribosome starts translation when it reads a start codon
- The large subunit joins and a tRNA transports the first amino acid to the A site
- The first amino acid is moved to the P site, where a peptide bond is formed
- Another tRNA delivers the next amino acide and the process continues
- When the ribosome sees a stop codon, a release factor (RF) binds to it
- RF binding causes everything to break apart
Normal Sequence: AUG - UUA - GUC - AGA
Mutated Sequence: AUG - UUG - GUC - AGA
Silent
Normal Sequence: AUG - UUA - GUC - AGA
Mutated Sequence: AUG - UUA - GUC - AGU
Missense
Normal Sequence: AUG - UUA - GUC - AGA
Mutated Sequence: AUG - UUA - CGU - CAG - A
Insertion
Normal Sequence: AUG - UUG - CAC - AGA
Mutated Sequence: AUG - UAG - CAC - AGA
Nonsense
Write one condition in either animals or humans that results from a missense mutation.
Sickle cell disease
Write 1 condition in either animals of humans that results from a deletion mutation
Marble bone disease
OR
Belgian Blue cattle (Hulk disease)
Why does PCR use Taq polymerase instead of eukaryotic DNA polymerase?
Taq is more heat resistant
List and describe the 3 main steps of PCR
- Denaturation - temp is increased and separates the 2 DNA strands
- Annealing - temp is cooled down and the primers bind to the DNA templates
- Extension - temp increases and taq enzyme lays down new nucleotides
Using a calculator, how many copies of DNA can you get from 8 cycles of PCR?
256
Explain how PCR was helpful for solving the murder case.
Increased amount of DNA for forensic testing
