Nucleotide

Organic compound composed of a pentose (five carbon sugar), at least one phosphate group and a nitrogenous base such as adenine (A), guanine (G), cytosine (C), thymine (T) in DNA or uracil (U) in RNA.
Nucleic acids like DNA and RNA are polymers of nucleotides connected by a phosphodiester link between the 3'C of one nucleotide and the 5'C of the next one. When on a double strand, the nitrogenous bases form three hydrogen bonds between cytosine - guanine and two between adenine - thymine or uracil.
Nucleotides can also be found free, participating in cell signaling (cGMP and cAMP), incorporated into important cofactors of enzimatic reactivos (NAD and FAD) or carrying packets of energy within the cell (ATP).

BA Group 14
Ana Isa Minnaert
Ana Rita Dias
Mónica Leiras
Paulo Guimarães

Translation

Process that occurs in the cell cytoplasm and also across the membrane of the endoplasmic reticulum, in eukaryotes, in which the codons in the mRNA, that accrue from the nucleus, are decoded into amino acids by molecular structures, which include the ribosomes. These structures “read” the mRNA by binding tRNA with complementary anticodon sequences in the mRNA.

The tRNA carries the amino acids that will combine due to combination of peptidical bonds and later fold into an active protein. 

Curso: Biologia Aplicada 2º ano

UC: Genes e Genomas 

Ano lectivo:2013/14

Elaborado por grupo 4

Alice Oliveira a70094

Carina Cerqueira a70091

Joana Rodrigues a68924

Rita Araújo a68869

Purines

               Purines are one of the two groups of nitrogen-containing organic molecules: the nitrogenous bases. The molecules of this family are non-polar and planar. Nitrogenous bases are, mostly, involved in the structure of the genetic material in living organisms.

                All purines are considered heterocyclic molecules, which have a double-ring structure that consists of a pyrimidine ring fused to an imidazole ring.  Each purine’s ring has two nitrogen atoms, which are located in the same place in all purines. The other positions within the rings are occupied by carbon atoms.  The purine ring is encircled by hydrogen atoms, which can be replaced by other atoms or groups of atoms, generating other forms of purines.

                This group of nitrogenous bases is very abundant in nature. We can find it in the nucleic acids: adenine (6-amino purine) and guanine (2-amino-6-oxypurine) are two of the five bases of DNA and RNA structure.  Caffeine and theobromine are also purines, present in plants, known because of their stimulant proprieties.

                We don’t find this kind of molecules only in DNA or RNA in our cells. They also have an important role in metabolic processes. Take the example of ATP, adenosine triphosphate, which derives from adenine.  Its ability to store and transfer energy, which also happens with GTP and coenzyme A, allows this molecule to interfere in almost every metabolic processes. 

Curso: Bioquímica 2ºano
UC: Biologia Molecular
Ano letivo: 2013/2014
Grupo de trabalho 5:
Ana Raquel Bertão A67384
Ana Margarida Pacheco A67372
Helena Rodrigues A67383
Renata Oliveira A67356

Pyrimidine

Pyrimidines are organic compounds like benzene, however its ring is heterocyclic, two nitrogen atoms replace carbon atoms in positions 1 and 3. This class of nitrogenous bases is represented by cytosine (C), thymine (T), uracil (U), fluorouacil, barbituric acid and orotic acid. Cytosine and thymine appear in DNA and they are responsible for base pairing with purines by hydrogen bonds. The incorrect metabolism of pyrimidines can cause serious diseases such as dihydropyrimidine dehydrogenase, which is inherited.

Curso: Bioquímica
UC: Biologia Molecular
2013/2014
Grupo 4:
 Ana Catarina Martins, A67362
 Diana Carneiro, A67345
 Madalena Monteiro, A67352

Hydrogen bond

Hydrogen bond is a special type of dipole-dipole interaction that occurs between an atom of hydrogen and the most electronegative elements as oxygen (O), nitrogen (N) or fluorine (F). This kind of bond is stronger than van der Waals interactions, but weaker than covalent or ionic bonds. In hydrogen bonds the electronegative atoms attract the electrons of hydrogen atoms, creating a dipole, the hydrogen atom being positive and the electronegative atom negative. The hydrogen bond is the stronger  intermolecular interaction.
The best example of this interaction is the molecule of water. This molecule has polar ends that allows water do create hydrogen bonds with others molecules of water. As shown in the image:

Licenciatura em Bioquímica
TP1, Grupo 1
Beatriz Pereira
Catarina Ribeiro
Joana Gomes
José Ribeiro

Covalent Bond

A covalent bond is a chemical bond, which involves sharing equally a pair of electrons between two atoms, forming a stable molecule. Usually, each atom gives one electron to form the bond.
The covalent bonds can be split into two groups, the simple and the giant covalent bonds. The giant ones are stronger than the simple ones due to the inter-molecular forces of attraction. 
Chemical bonds also include the ionic bonds, however, unlike the covalent bond, this bond is formed when two ions bind together because of the attraction between the opposite charges. 
Covalent bonds are also stronger than ionic bonds.

Curso: Bioquímica
UC: Biologia Molecular
2013/2014
Título: "The Covalent Bond"
Tarefa: Definição de ligação covalente

Ana Catarina Macieira
Ana Lima
Bruno Lima
Diogo Araújo

Hydrophobic Effect

Hydrophobic Effect is an effect that expresses a tendency by certain non-polar substances that have an aversion to water and therefore do not allow the junction of lipid molecules together to form intramolecular or intermolecular aggregates when present in polar solvents.

Such substances are called hydrophobic.

At the molecular level this effect becomes important for protein folding and formation of micelles and lipid bilayers.





Biochemistry 2013, Caroline Pereira, Hugo Silva e Juliana Rocha