Central Dogma in Molecular Biology Flashcards
producing 2 identical copies of the original DNA.
DNA replication
DNA replication occurs during what phase of the cell cycle before cell division.
S phase
must be accurately copied to ensure each daughter cells receives exact genetic information as of the parent cell.
DNA
synthesized a primer that will start the replication.
Primase
a short sequence of RNA with a 3’ end than can be elongated by DNA polymerase.
Primer
add new nucleotides to growing strand
DNA polymerase III
removes primer (since it is RNA) and replace by DNA
DNA polymerase I-
DNA pol III elongates the primer by adding new bases, growing the strand in a 5’ to 3’ direction
Leading strand-
DNA pol III adds nucleotides (backward direction) from the replication fork producing short segment called Okazaki fragments.
Lagging strand-
Lagging strand- replication fork producing short segment called
Okazaki fragments.
joins together or sealed the okazaki fragments by addition of phosphate group.
DNA Ligase-
Types of DNA repair mechanism
Base excision repair (BER)
Nucleotide excision repair (NER)
Mismatch repair (MMR)
Double strand break repair
Homology directed repair
It Repairs single base that undergone alkylation, deamination of oxidation.
Base excision repair
Various enzyme (glycosylase, endonuclease, polymerase and ligase) remove mutated base from the double helix (excision) and replaced it with a normal.
Base excision repair
These chemical process if not corrected can lead incorrect base pairing resulting in substitution or deletion of bases.
Base excision repair
Detects and repair distortion (bulky) to the DNA strand as result of environment such a sun UV light ad some chemotherapeutic drugs.
Nucleotide excision repair (NER)
DNA glycosylase detects damaged bases.
Base excision repair
causes bulky DNA adducts.
Thymine dimerization
Wide strand that contain the lesion is excise (remove) and DNA polymerase enzyme synthesized the new strand
Nucleotide excision repair (NER)
Repair spontaneous base–base mis pairs and small insertions–deletion loops generated during DNA replication or recombination
DNA mismatch repair (MMR)
recognizes the mismatch to be followed by recruitment of repair enzymes that excise incorrect sequence.
DNA mismatch repair (MMR)
DNA polymerase and ligase resynthesized new strand using the parental strand.
DNA mismatch repair (MMR)
Repair double stranded breaks (DSB)
Homologous recombination repair (HR)
The repair mechanism is active during S ang G2 phase.
Involves unwinding of the damaged DNA helix and invasion of the damaged strands into a homologous DNA duplex molecule.
Homologous recombination repair (HR)
The sister chromatid or homologous chromosome is used as template for synthesizing new strand.
Homologous recombination repair (HR)
Also repair double strand breaks (DSB)
It is active throughout the cell cycle.
Error prone.
Repair mechanism does not need homologous template
Non homologous end joining repair (NHEJ)
changes in the base sequence of DNA resulting to genetic variation among organisms, in the case of human it causes disease mostly are malignant condition.
Mutation
are cause by environment like radiation, UV light, carcinogens and internal factors such as spontaneous mutation.
Mutation
Extreme exposure to environment increases the rate of
Mutation
The process of transferring the genetic information from DNA to RNA.
Transcription
A particular gene is transcribed in response to the need of the cell.
Transcription
catalyzes by reverse transcriptase enzyme producing complimentary DNA (cDNA) from mRNA.
Reverse transcription-
located upstream contains TATA box, recognition site for transcription.
Promoter region
located downstream. Forms a hairpin-like strand signaling the end of transcription.
Termination region
structure of a gene is consist of a
Promoter region
RNA-coding region
Termination region
these are proteins that regulates transcription process (when to turn on and how much).
Transcription factors-
is a mark where RNA polymerase bind and start copying the DNA strand. In eukaryotes it is known as TATA box.
Promoter
The RNA polymerase unwinds the DNA exposing 10-20 bases at a time forming the transcription bubble.
One strand is only needed for the transcription (template strand).
Elongation
Elongation in what direction
5’ - 3’
The RNA pol stops moving on the DNA template after reaching the termination region.
Termination
The transcribed RNA is a single stranded complementary copy of one of 2 strands
Elongation
Transcription stops, transcribed RNA is release from the template strand.
Termination
RNA modifications (maturation of RNA) process occurs in ?
Nucleus
removal of introns(non-coding protein) and rejoining of exons (protein-coding gene). This process is catalyzed by
Splicing
spliceosome.
A process of decoding biologic information from mRNA to synthesize a protein.
Translation
Translation occur in the?
Ribosome
Enzymatic process of amino acid side chain modification after their protein biosynthesis.
Post Translation modification
It result to protein diversity.
Post Translation modification
A molecular laboratory technique used in clinical diagnostics.
Polymerase chain reaction
An in-vitro amplification/replication of DNA/RNA fragments through a cycle of heating and cooling.
Polymerase chain reaction
Generates millions of copies of DNA after the process.
Invented by MULLIS in 1983.
Polymerase chain reaction
Components of PCR
DNA template/fragment- from the sample
Primer (synthetic)
Taq DNA Polymerase
Synthetic deoxynucleotide triphosphate- dNTPs
Buffer
These are fragments of interest or the target DNA for amplification, serves as a template.
DNA fragments
are present in biological samples. They are need to be purified and isolated from the sample before the actual PCR.
DNA fragments
Single stranded DNA (10-30 nucleotides) synthesized chemically(synthetic primer).
PRIMERS
Serves as the starting point for the amplification.
PRIMERS
Adds dNTPs to the growing strand of DNA.
Taq DNA Polymerase
Extracted from Thermus aquaticus a bacteria that lives in hot springs a can withstand hot temperature (> 100 C).
Taq DNA Polymerase
Provide nucleotides during DNA amplification.
dNTP- Deoxynucleotide triphosphate
Polymerase chain reaction process
Denaturation
Annealing
Extension
At 94 C the double-stranded DNA melts and opens into two pieces of single-stranded DNA
Denaturation
At 54 C the primers pair up (anneal) with the single-stranded template.
Annealing
at 72 C DNA polymerase extends the primer by its polymerase activity by adding dNTPS.
Extension
Polymerase chain reaction process cycle repeat for?
25-40 times to make a million copies of DNA sequence.
A technique used for identification and quantification of RNA.
RT-PCR
is used to allow a single strand of RNA to be transcribe into a complementary strand of DNA (cDNA).
reverse transcriptase enzyme
used to detect and study many RNA viruses.
RT-PCR
