Central dogma
What is the primary function of a DNA in the central dogma?
DNA stores genetic information.
What is transcription?
transcription is a production of RNA using DNA as a template, the new RNA transcript can only be built by adding on to the 3 Prime end (builds antiparllel)
How do we achieve diversity in organisms?
Diversity comes from changing how the gene is regulated. Gene regulation help cells control gene expression.
What determines how a protein Folds?
the side chains, that would either absorb or donate proteins
What are the two types of regulatory RNA found in eukaryotes?
Micro RNA (transitory) - binds to mRNA and prevents them from translating. mRNA is actively inhibited
Small inhibitory/interfering RNA - Bind to RNA and mark them for degradation, this permanently inhibits translation and eventually the mRNA is destroyed
Transcription uses enzymes to do what in the central dogma?
Transcription (reading of mRNA) will use enzymes to synthesize proteins
Does it matter which parental strand is read?
No, genes can exist on either strand so either strand can be read by the enzyme RNA polymerase and be used to make RNA transcript.
How is the transfer from heterochromatin to euchromatin controlled?
This process is controlled by the amount of methylation on a histone tail.
Remember heterochromatin cannot be transcribed because of lack of space since it is... tightly wound chromatins.
What is the mechanism behind peptide bond formation?
Dehydration synthesis, an oxygen is pulled off a carboxyl group and is combined with a hydrogen of the amino group to form water.
The water gives the energy needed to make a new bond between the carbonyl group and amine group which we call a peptide.
What is the importance of an operon( functional units of genes)?
operons allow for ultimate transcription and ultimate translation of a series of protein all dedicated to one task ( this task is one that's usually necessary for life)
What are the three parts of a nucleotides?
Phosphate Group
Sugar
Nitrogenous Base ( A,G,C,T)
how does transcription start and end?
transcription starts at a promoter sequence, known as the TATA box , and ends at a Terminator sequence.
What is the importance of euchromatin?
Unwound chromatin is euchromatin. Cells decide when it's time for transcription to deactivate or activate by examining euchromatin.
what is the importance of methionine?
all of life start with methionine
How do RTF’s(activator proteins) control transcription?
RTF's controls transcription by either allowing for transcription to take place ( activators) OR preventing/ repressing transcription to take place (silencers).
Why is ntp important?
Nucleoside triphosphates are the only nucleotides that can be used to build nucleic acids.
Why are transcription factors necessary?
In most living organisms especially eukaryotes the RNA polymerase cannot bind on its own, it needs other proteins known as transcription factors. Transcription factors have two main jobs to (1)bind to the promoter and (2)to flag the RNA polymerase.
How is methylation on CpG Islands (phosphate backbone) used to shut off transcription?
Extensive methylation of cpg islands can cause the nature of the promoter to change, when the promoter changes it will no longer allow for RNA polymerase to bond therefore, effectively shutting off transcription.
Describe the function of tertiary structured proteins?
The tertiary structure is determined by the side chains, any potential interaction can help maintain the tertiary structure.
Tertiary structures are held together by hydrogen bonds but all other bonds can be involved in a tertiary structure.
Eg. disulfide Bridges= covalent bonds
Eg. acidic/ basic side chains= ionic bonds
What does the large and small subunit of a ribosome do?
The large subunit holds the tRNA molecules in place while the peptide bonds are formed , the small subunits binds to the mRNA strand.
What is the importance of hydrogen bonds and DNA's antiparallel orientation?
Because DNA utilizes hydrogen bonds and base stacking this very stable configuration allows DNA to easily coil around itself and be very long.
How is a polymerization reaction an example of dehydration synthesis?
Breaking bonds means you are releasing energy.
Why is it important? because of the second law of Thermodynamics, energy must be spent in order to decrease entropy, so when you're building anything you're spending energy.
Therefore when you are engaged in dehydration synthesis that bond between the first and second phosphate contain a lot of energy; so the more phosphates you add the more energy you release.
Why would cells favor unmethylated CpG Islands?
Unmethylated CpG islands result in a functional promoter.
Methylated cpg islands make promoters non-functional this is important when trying to regulate genes based on changing environment.
what is the importance in denaturing/ misfolding of proteins?
All proteins need to be a specific shape, therefore denaturing proteins could result in a cessation of life.
When a protein is misfolded it is not able to maintain functions necessary for life.
Proteins are denatured through change in temperature pH and solutes.
How does the initiation step of translation differ in prokaryotes vs. eukaryotes?
Eukaryotic initiation is monocistronic , One mRNA can make one protein to do a specific function.
Prokaryotic initiation in translation is polycistronic, one mRNA can make more than one protein to do a specific function , this also increases efficiency.