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 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 metaphasic/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
G. and . S: DNA . (). G and genes divide. .