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Genetic code: 1. Each codon or triplet code for specific amino acids.  2. It is degenerated: Amino acids can be determined (coded) by more than one codon or triplets (some triplets are synonyms: There are 64 codons for 20 aa).  3. It is not ambiguous: Each codon only encodes a type of amino acid.  4. It is universal: Apart from a few small exceptions. 5 There are triplets that determine: The beginning of the translation ('start codon'): AUG (It codes  for the amino acid methionine - Met) The end of the translation ('termination or stop codon'): UAA, UAG, UGA (They do not code for any amino acids.

Chromosomes: They are stick-shaped structures which arise from the condensation and packaging of chromatin, during the division phase (mitosis and meiosis). They are made up of DNA + proteins (histones). They have a constricted area (centromere) that divides them into two arms (equal or different length) There are: Simple chromosomes: 1 chromatid.  1 centromere that divides it into 2 arms.  -They are called anaphasic chromosome. Duplicated or replicated chromosomes: 2 sister chromatids (one is copy of the other: Replication).  1 centromere that joins both chromatids and divides the chromosome and its chromatids into arms.  2 kinetochores or disc-shaped proteins assemble on the centromere, which are essential during cell division cellular (They appearinprophase) They are called metaphasicchromosome.Metacentric/submetacentric/acrocentric/telocentric

1st stage: The DNA unwinds, and the two chain separate.  2nd stage: Each DNA is duplicated independently, serving as a template for a new complementary DNA chain (A = L; GEC), by the enzyme DNA polymerase or replicase 3rd stage Two identical double helixes are obtained, each of which is made up of  a new chain and an old one.  This is known as semiconservative replication

G1:Synthesisofproteinsforthecelltoincreaseinsize. Formationorduplicationofcellorganellesand cytoplasmicstructures. S: DNA replication. Synthesisofhistones(proteins). G2:Transcription and translationof genes thatencodeproteinsnecessaryforthecellto divide. Duplocationofcentrioles.