DNA Structure & Replication
What enzymes adds nucleotides in DNA replication?
DNA Polymerase
What is the flow of genetic information?
DNA --> mRNA --> Protein
What does it mean for genes to be expressed?
They are used to make a protein.
What type of DNA mutation only affects one nucleotide?
A point mutation.
What is genetic engineering?
Manipulating genes/changing DNA of an organism
What are the components of a nucleotide?
Deoxyribose, phosphate & Nitrogenous base
Noncoding strand or template strand or antisense strand
In Prokaryotes, what kind of operon is usually on, but can be turned off in regulation?
Repressible operon
What is a silent mutation?
One nucleotide is replaced with a different one, but it doesn't change the amino acid or affect the protein.
In gel electrophoresis, what sized DNA fragments move the farthest?
Small fragments
Which nitrogenous bases form 3 hydrogen bonds?
Cytosine and guanine
What are 3 things that happens to premRNA before translation?
1. Removal of introns
2. Addition of 5' cap
3. Addition of poly A tail
In eukaryotes, what does methylation do?
Binds to DNA to make it more tightly wound around histone proteins.
What does it mean to have a frameshift mutation?
The codon reading frame is shifted so all subsequent amino acids are affected.
What is the process that amplifies DNA?
PCR
How is topoisomerase different from helicase?
Topoisomerase unwinds the DNA strand, helicase unzips it.
What is the role of mRNA, tRNA and rRNA in translation?
mRNA has the codons that code for the protein
tRNA transfers amino acids to the mRNA by matching anticodons with the codons
rRNA is a component of the ribosome and acts as a binding site for tRNA
Describe the role of a corepressor in an inducible operon.
A corepressor activates a repressor by binding to it which will then bind to the operator to stop transcription.
What are three specific point mutations that would definitely lead to mutated proteins?
1. Deletion
2. Insertion
3. Nonsense mutation
What happens in bacterial transformation?
A plasmid is incorporated into the bacterial DNA.
What are three enzymes that work on the lagging strand in DNA replication and what do they do?
1. RNA primase adds primers
2. DNA Polymerase adds nucleotides
3. Ligase joins the okazaki fragments
Describe what initiates termination in transcription and translation.
Translation- a stop codon causes the release of the protein from the ribosome.
In eukaryotes, what are 3 components involved in a transcription initiation complex that allow RNA polymerase to bind?
1. Activator protein
2. Enhancer DNA sequence
3. Transcription factors
(also mediator proteins)
What are 4 mutations that can occur at the chromosomal level?
1. Nondisjunction (leading to aneuploidy or polyploidy)
2. Inversion
3. Deletion (of genes)
4. Translocation
5. Duplication
What is the role of restriction enzymes in gel electrophoresis?
Restriction enzymes cut DNA strands at specific locations and when that sample is put through gel electrophoresis, the fragments separate.