Experiment 1: Genetic Information Transfer Flashcards
Define Genetic Information Transfer (GIT)
The process required to produce a protein or functional RNA using the information stored in genes is called genetic information transfer.
How is the process of genetic information transfer started?
Gene information transfer starts when a gene is turned on or EXPRESSED. The DNA is then transcribed or copied into pre-mRNA using the enzyme RNA Polymerase and the process of transcription. The DNA of the gene is not modified and thus is not converted to mRNA- it is copied or transcribed.
What is the process of mRNA Processing (eukaryotes)?
After transcription, the pre-mRNA is processed in three ways: a “cap” is added to the start, a string of adenines is added to the end (poly-A tail) and the pre-mRNA is spliced to remove the introns.
Define Intron
A segment of a DNA or RNA molecule which does not code for proteins and interrupts the sequence of genes.
Is the coding sequence for a protein in eukaryotic genes continuous?
No
What are the coding and non-coding sequences called respectively?
Coding: Exon. CE
Non-Coding: Intron (in between the exons) NI. NICE
What happens to introns and exons in the splicing process?
Introns are removed and exons are spliced together. (To splice means to join)
Where does splicing occur?
Splicing occurs in a very complex set of proteins and RNAs called the spliceosome. SPR (Spliceosome-Protein-RNA)
What happens in the process of translation?
In the cytoplasm, the mRNA meets up with the machine that will decode the mRNA and produce a string of amino acids. This machine is the ribosome and contains both proteins and rRNAS (ribosomal RNA). The sequence of the mRNA is read in groups of three nucleotides (a codon) and the tRNA with the complementary sequence enters the ribosome. An amino acid is attached to the tRNA and the ribosome transfer the amino acid to the growing protein. When the ribosome reaches a stop codon (UAA, UAG, or UGA), the protein is released to perform its function and the mRNA can be transplanted again.
Why are control reactions important?
If the experiment does not work, the controls provide reasons why.
What are the two types of controls?
Negative-Positive
What should be seen with negative controls?
No result should be observed. If a result is observed in the negative control, it suggests that an error occurred during the experimental set-up or the reagents used were contaminated.
How are positive controls used?
Positive controls are used to confirm previously characterized results in a new sample or to confirm that all reagents were added properly.
What do all PCR reactions contain?
Enzyme, dNTPs, buffer, and water. EDB-W
What are the variable reagents in the experiment?
Primers
What do primers do in the experiment?
The primers direct the polymerase to the region of DNA for copying. In this experiment, primers bind around the Actin Gene.
Define Transcription
The process by which a cell makes an RNA copy of a piece of DNA. This RNA copy, called messenger RNA (mRNA), carries the genetic information needed to make proteins in a cell. It carries the information from the DNA in the nucleus of the cell to the cytoplasm, where proteins are made.
Define Translation
The process by which a cell makes proteins using the genetic information carried in the messenger RNA (mRNA). The mRNA is made by copying DNA, and the information it carries tells the cell how to link amino acids together to form proteins.
Define DNA
The molecules inside cells that carry genetic information and pass it from one generation to the next. Also called deoxyribonucleic acid.
Define pre-mRNA
The first transcript from a protein coding gene is called a pre-mRNA and contains both introns and exons. Pre-mRNA requires splicing (removal) of introns to produce the final mRNA molecule containing only exons.
Define mRNA
A type of RNA found in cells. MRNA molecules carry the genetic information needed to make proteins. They carry the information from the DNA in the nucleus of the cell to the cytoplasm where the proteins are made. Also called messenger RNA.
Define tRNA
A small molecule that plays a key role in protein synthesis. Transfer RNA serves as a link (or adaptor) between the messenger RNA molecule and growing chain of amino acids that make up a protein. Each time an amino acid is added to the chain, a specific tRNA pairs with its complementary sequence on the mRNA molecule, ensuring that the appropriate amino acid is inserted into the protein being synthesized.
Define Splicing
The process by which introns, the non coding regions of genes, are excised out of the primary messenger RNA transcript, and the exons (coding regions) are joined together to generate mature messenger RNA.
Define Spliceosome
A large RNA-protein complex that catalyses the removal of introns from nuclear pre-mRNA.
Define Ribosome
An intercellular structure made of both RNA and protein which is the site of protein synthesis in a cell.
Define DNA Polymerase
A type of enzyme that is responsible for forming new copies of DNA, in the from of nucleic acid molecules.
Define RNA Polymerase
An enzyme that is responsible for copying a DNA sequence into an RNA sequence, during the process of transcription.
Explain the process from DNA to Cell
First, we start off with the cell.
Most cells have a nucleus. The nucleus contains the genome. In humans, the genome is split between 23 chromosomes. Each chromosome contains a long strand of DNA, tightly packaged around proteins called histones. Within the DNA, there are sections called genes. These genes contain the instructions for making proteins. When a gene is switched on, an enzyme called RNA Polymerase attaches to the start of the gene.
It moves along the DNA, making a strand of mRNA to free bases in the nucleus. The DNA code determines the order in which the free bases are added to the mRNA. This process is called TRANSCRIPTION.
Before the mRNA can be used for a template for the production of proteins, it needs to be processed. This involves removing and adding sections of RNA. The mRNA then moves out of the nucleus unto the cytoplasm. Protein factories in the cytoplasm called Ribosomes bind to the mRNA. The ribosome reads the code in the mRNA to produce a chain made up of amino acids. There are 20 different types of amino acids. Transfer RNA molecules carry the amino acids to the ribosome. The mRNA is read three bases at a time. As each triplet is read, a tRNA delivers the corresponding amino acid. This is added to a growing chain of amino acids. Once the last amino acid has been added, the chain folds into a complex 3D shape to form the protein.
In the most basic terms, what are the processes of Translation and Transcription? Which comes first?
Transcription comes first, then translation.
Transcription is the process of DNA turning into mRNA.
Translation is the process of mRNA turning into protein.
In which site of the cell are proteins manufactured?
Ribosomes
Define Enzymes
Proteins that act as biological catalysts by accelerating chemical reactions.
How is a gene defined in this class?
A region of the DNA that coeds for proteins.
What are genes consisted of?
Introns and Exons
What is removed during the splicing process?
Introns
What is going to be compared in the experiment?
Genomic DNA and the cDNA of the Actin gene is going to be compared.
Is cDNA a naturally occurring thing?
No
What technique is going to be relied on in order to determine the gene structure?
Polymerase Chain Reaction. (PCR)
Can PCR work with a single stranded piece of DNA?
No
What are the 2 forms of the Actin Gene?
Genomic DNA and cDNA
What are the 3 traits of DNA?
Variable-Dynamic-Heritable VDH
One of the major changes in DNA are _____
Mutations
Mutations have the potential to lead to _____
Cancer
Define Vertical Transmission
The passing down of traits from generation to generation
What are the spaces in between exons called?
Introns
______ control the expression of the gene.
Promoters
Which organelle has its own genome in humans? Where do we get it from?
Mitochondria-Mothers
Is cDNA continuous?
Yes
cDNA is a copy of _____ (in DNA form)
mRNA
What is the formula for finding % gel?
(Mass/Volume)x100 ; mass is in grams; volume is in mL.
What is the relationship between the % associated with the gel and the density of the gel?
The higher the %, the more dense the gel; the lower the gel %, the better it is to discriminate larger bonds.
What aspect of the DNA gives it a certain charge? What properties does it give it?
Sugar Phosphate backbone makes DNA negatively charged; it gives it acidic properties.
The buffer that was used to fill the rig is good at _____.
Conducting Electricity.
How does the increased presence of G’s and C’s in a DNA sequence impact the annealing and Denaturation process?
The more G’s and C’s in a sequence, the lower temperature required for annealing; higher temperature is required for Denaturation.
What is the temperature range for Annealing?
50s to 60s
What is the temperature for Denaturation?
95 or 98
What is the temperature for Extension?
72.
Define Denaturation in PCR
When the double-stranded template DNA is heated to separate it into two single strands.
Define Annealing in PCR
When the temperature is lowered to enable the DNA primers to attach to the template DNA.
Define Extension in PCR
When the temperature is raised and the new strand of DNA is made by the Taq Polymerase enzyme. ET
Which DNA of the Actin Gene should be longer?
Genomic DNA due to the presence of introns and exons.
When doing alignment in the nCBI blast, how should you sort it?
Sort by Query Start
In Gene Diagrams, what are the numbers on the top?
Query # Ranges
When you get 1 band as a result of the experiment, what happened?
You forgot to add enough DNA, you lost the sample, there was improper loading, or there was leakage.
If there are no bands at all as a result of the experiment, what happened?
You forgot to add the primers.
When doing alignment, what should be done in terms of placement of sequences?
The longer sequence should always be on top.
Define Primer
a short single-stranded nucleic acid used by all living organisms in the initiation of DNA synthesis.
Define Exon
Segments of DNA or RNA that are responsible for coding proteins.
