Visas : Visas for Portugal are not required by all nationals referred to in the chart above. Nationals of Australia, Canada and the USA can stay for up to 90 days without a visa.EU nationals can stay for an unlimited period, but must register with the local authorities after three months.ationals of Australia, Canada and the USA can stay for up to 90 days without a visa. EU nationals can stay for an unlimited period, but must register with the local authorities after three months.
RNA (Ribonucleic Acid). RNA is a nucleic acid consisting long chain of nucleotide units. Like the DNA molecule, every nucleotide consists of a nitrogenous base, sugar and phosphates. RNA is created by a process known as Transcribing, which involves the following 4 steps: 1  DNA âunzipsâ as the bonds break. 2  The free nucleotides lead to the RNA pair up with the complementary bases.
RNA is single stranded,rna has uracil instead of thymine, rna has ribose sugar while dna has deoxyribose,rna is found everywhere in the cell and dna is only in the nucleus. Name three differences between dna & rna. helicase-the enzyme-unzips the two strands of a dna molecule at the hydrogen bonds between the paired nitrogen bases. what is the first step of dna replication and what enzyme is involved in this step.