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DeoxyriboNucleic Acid

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This is called the doble helix structure, composed by two strands that are twisted but never touches each other.

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If we zoom in, this is what composes the DNA, are called Nucleotides and are structured in an antiparallel position.

The parts of the nucleotides are called deoxyribose (sugar), phosphate group (acids), and nucleobase (nitrogenous base).

They also have bonds called Covalent bonds, which are located between the different parts of the nucleotides, there is also a Hydrogen bond, that lightly attaches the nucleobases from both DNA strands.

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Enzyme: protein with a function

Topoisomerase: enzyme that un-coils the double helix

Helicase: separates the 2 strands of DNA

SingleStrandBindingProteins: stabilizes the DNA molecules

Primase: adds a primer

Primer: Short sequence of nucleotides to start the new strand

DNA Polymerase I: Changes the primers (made of RNA) for DNA

DNA Polymerase II: Makes sure the two strands of DNA were duplicated correctly. If there is any mistake it corrects it.

DNA Polymerase III: Synthetise the new strand. Can only build 5' - 3'

Ligase: Closes the gaps left in the DNA

Termination Signal: Signal written in the DNA (is nothing especial just a part of the DNA) which tells the enzime to stop the transcription

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This shows the chemical structure of the DNA (also showing the ribose version), and the prime numbers labeling

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of molecular biology

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in your DNA it has a nuclear code special to you containing a mixed order of T, A, G, C "language" (names in the image). But it's complementary strand can only connect with a certain pair as u can see, only A & T go together and G & C (If there is any other combination that are not these options, a mutation can occur)

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the DNA is too important to leave the nucleus so they create a messenger: RNA

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It still in the double strand form and not readable yet

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When the strands begin to split for replication, a copy starts forming to match the one previously, it's like filling in the gaps with the same code A=T / C=G

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In the first part of the first step of the replication, we have the Topoisomerose, which is an enzime that is in charge of untwisting the DNA strands

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Once the topoisomerose untwisted the DNA strands, the Helicase appears and separates the strands. At the same time, the little red balls called S.S.B.P or Simple Strand Biding Proteins make sure the strands dont twist again and stabilizes the DNA molecule.

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Is important to mention that the enzimes are MOVING (are not static like in the image) and all the steps happen all together at the same time

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Then, it appears the Primase, which is an enzyme that synthesizes short RNA sequences called primers. The primer is a short nucleic acid sequence that provides a starting point for DNA synthesis.

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After that, another enzyme that catalyzes elongation of DNA chains during bacterial chromosomal DNA replication called DNA polymerase III continues the new DNA strand that the primer started. IT CAN ONLY MOVE IN DIRECTION 5´ TO 3´

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Having already done the first strand which is called the Leading strand, then the only thing we are missing is the other strand called the Lagging strand, the problem is that the DNA polymerase can just move in direction 5´ to 3´. What causes that everytime the primase places a primer, the DNA polymerase can only work in ONE LITTLE SPACE, so everytime the other enzimes (Topoisomerose and helicase) move, the primase needs to place another primer and the DNA polymerase needs to complete it over and over again. This is what causes that in the Lagging strand is conformed by Okazaki fragments (Okazaki is the surname of the couple of scientists that discovered them).

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The problem with the primase is that they are made up of RNA, which means with time they desappear. So, what are body does to fix this is creating the DNA Polymerase I, which is in charge of changing the primase with real DNA. In the image, its work is represented in the dark purple parts. Even though, we still have some gaps in the lagging strand...

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The ligase (the yellow thing in the image), is in charge of closing those little gaps that are missing in the DNA, converting this

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Finally, in the last step of Replication, the two DNA molecules TWIST back into the double helix. and the DNA polymerase II checks both strand to make sure it was done correctly.

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A messenger made from DNA to leave the nucleus and build protein (has an extra Oxygen).

It also has a different nuclear code called Uracil, which replaces the Thymine. It consists of only 1 strand, which is reactive and denigrates over time

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The RNA polymerase does all the work in this stage as it uncoils, separates, builds, and recoils the 2 strands, while it is attached to the promoter. in this part it is currently just separating and placing itself between the 2 strands

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RNA chain complementary to the template strand of DNA is synthesized as RNA polymerase moves along DNA (using uracil when there's adenine).

The polymerase builds in the 5' -> 3' direction,

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The RNA polumerase detects the termination signal and dettaches. Ends the process

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In bacteria, RNA transcripts can act as messenger RNAs (mRNAs) right away. In Eukaryotes, the transcript of a protein-coding gene is called a pre-mRNA and must go through extra processing before it can direct translation.

Eukaryotic pre-mRNAs must have their ends modified, by addition of a 5' cap (at the beginning and 3' poly - A tail (at the end).

Many eukaryotic pre-mRNAs undergo splicing. In this process, parts of the pre-mRNAs (called introns) are chopped out, and the remaining pieces (called exons) are stuck back together.

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End modifications increase the stability of the mRNA, while splicing gives the mRNA its correct sequence. (If the introns are not removed, they'll be translated along with the exons, producing a "gibberish" polypeptide.)

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mRNA: RNA molecule that comes out of transcription

ribosome: where protein synthesis takes place (big subunit, small subunit

codon: sequence of 3 nucleotides

tRNA: transfer RNA, it has an anticodon and carries aa

aa: Aminoacid, monomere of a protein

AUG: Starting codon. codifies for metionine (Met)

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Research:                   Post-transcriptional modifications in eukaryotes (L8 11/02)

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Research:                   Post-transcriptional modifications in eukaryotes (L8 11/02)

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Processing steps that convert a primary RNA transcript (pre-mRNA) into a mature messenger RNA (mRNA) that can be translated into a protein. These modifications occur in the nucleus before the mRNA is transported to the cytoplasm for translation.

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Eukaryotic genes contain introns "in" (non-coding regions) and exons "exit" (coding regions).

Splicing removes introns and joins exons together to form a continuous coding sequence.

This is carried out by the spliceosome, a complex made of small nuclear RNAs (snRNAs) and proteins.

Alternative splicing allows different combinations of exons to be joined, increasing protein diversity.

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Shortly after transcription begins, a 7-methylguanosine (m⁷G) cap is added to the 5' end of the pre-mRNA.

This cap protects the mRNA from degradation, helps in ribosome recognition during translation, and assists in nuclear export.

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The pre-mRNA is cleaved at the 3' end, and a poly(A) tail (a string of adenine nucleotides) is added.

This tail stabilizes the mRNA, protects it from degradation, and aids in nuclear export and translation.

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In some cases, nucleotides in the mRNA are chemically modified or replaced, altering the final protein product.

Examples include A-to-I editing (adenosine to inosine) and C-to-U editing (cytidine to uridine).

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there is the RNA floating around when the big and small subunits place themselves under and on the RNA, to start the translation, the code must begin with A U G = MET

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in the big subunit there are 3 parts: Exit, Peptide bond, and where the New tRNA arrives.

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The peptide bond is where it begins, it places on the codon AUG and makes the copy of it, with the aa MET semi-attached at the top.

Each codon order has its own protein type

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The A is the step before the P, which is skipped for AUG, the next codon is in that site, the tRNA comes then replicates the code and places the aa on top (which in P it begins the separate) connecting to the aa of before making a line

The Exit is when the tRNA then removes from the RNA having the proteins floating above it

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This is the Protein Synthesis Genetic Code table

there are 3 codes that end the translation, we know about UAA, they don't codify for any aa so no peptide comes nothing

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It happens due to a mistake during DNA replication or cell division. A new sequence of DNA is produced. it is natural and happens all the time, your body detects it either fixing the mutation or killing the cell itself. if the mutation is left floating in your body, the cell can become a cancer cell. (if you have multiple mutation, there could be one that escapes the detection)

Mutagens: agent which produces or facilitates a mutation to occur.

◼ Physical mutagen: radiation (X-rays or UV)

◼ Chemical mutagens: some substances can cause changes in genes. Like for example pollutants, substances in tobacco. Risk of mutations increase with the increased exposure.

◼ Biological mutagens: some viruses can increase the frequency of genetic mutations, most known is the HIV virus (this virus causes the carrier to have cancer eventually).

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An extra nucleotide gets added to the DNA strand. changing the amino acid codons of the rest of the strand. This can happen when the replicating strand "slips," or wrinkles, which allows the extra nucleotide to be inserted. Strand slippage can also lead to deletion mutations.

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Missense: when the base changes and the amino acid also changes

Nonsense: when the base changes and the amino acid is a stop codon

Silent: when the base changes but the amino acid remains the same

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the opposite of insertion, a wrinkle can appear and block a nucleotide, which then leads to it being "deleted"

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A frameshift mutation is a type of genetic mutation that occurs when nucleotides (DNA or RNA bases) are inserted or deleted in a sequence, but not in multiples of three. Since the genetic code is read in sets of three nucleotides (codons), this shifts the reading frame, altering the way the sequence is translated into amino acids.

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Modification of an organism at a genetic level to do something it could not do before.

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the PCR makes a specific primer for a specific sequences, for example covid has a sequence so...

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works with PCR ..

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PCR with Fluorescent ddNTPs (Special DNA Building Blocks)

The DNA to be sequenced is first copied using PCR

A mix of normal nucleotides (A, T, C, G) and special fluorescently labeled ddNTPs (which act as "stoppers") is added.

Whenever a ddNTP (colored block) is added to a growing DNA strand, the chain stops growing at that point.

This process creates many different DNA fragments of varying lengths, each stopping at a different base (A, T, C, or G).

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Plasmid manipulation of bacteria (L11 25/02) 

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Plasmid manipulation of bacteria (L11 25/02) 

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Plasmids are small DNA molecules used to “trick” cells into producing a desired protein through its gene. they are ring shaped floating around the DNA, as i doesn't have a nucleus.

the first step is in the prompter where it activates the transcription of DNA.

the place where they put the new protein in is called the restriction site, it cuts to be able to insert the gene.

Selectable marker and Antibiotic Resistance Gene is to look for the cells that express the plasmids

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Polymerase chain reaction (abbreviated PCR) is a laboratory technique for rapidly producing (amplifying) millions to billions of copies of a specific segment of DNA, which can then be studied in greater detail. PCR involves using short synthetic DNA fragments called primers to select a segment of the genome to be amplified, and then multiple rounds of DNA synthesis to amplify that segment.

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Electrophoresis is a laboratory technique used to separate DNA, RNA, or protein molecules based on their size and electrical charge. An electric current is used to move molecules through a gel or other matrix.

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The DNA fragments are then passed through a gel-like material using capillary electrophoresis.

After the DNA fragments are separated by size, they pass through a laser beam in a sequencing machine.

The laser excites the fluorescent tags on the ddNTPs at the end of each fragment.

Since each type of nucleotide (A, T, C, G) has a different color, the machine can detect which base is at the end of each fragment.

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an example can be with insulin. you cut the plasmid at the restricted side, place some insulin gene between the cut, now that plasmid had insulin. since a bacteria doesn't need it, it will just keep releasing insulin. if that is done with any protein, that bacteria can produce it through its gene