Genetics information encoding

Nucleus The nucleus is separated from the cytosol by a double membrane, the nuclear envelope. The DNA is complexed with basic proteins (histones) to form chromatin fibers, the material from which chromosomes are made. A distinct RNA-rich region, the nucleolus, is the site of ribosome assembly. The nucleus is the repository of genetic information encoded in DNA and organized into chromosomes. During mitosis, the chromosomes are replicated and transmitted to the daughter cells. The genetic information of DNA is transcribed into RNA in the nucleus and passes into the cytosol where it is translated into protein by ribosomes. 

Transcription (Section 28.4) The process by which the genetic information encoded in DNA is read and used to synthesize RNA in the nucleus of the cell. A smal I portion of double-stranded DNA uncoils, and complementary ribonucleotides line up in the correct sequence for RNA synthesis. 

Transcription is the term used to describe the synthesis of RNA from a DNA template. Translation is the process by which information in RNA is used to synthesise a polypeptide chain. In a little more detail, the genetic information encoded in DNAis first transcribed into acomplementary copy of RNA (a primary RNA transcript) which is then processed to form messenger RNA (mRNA). This leaves the nucleus and is translated into a polypeptide in the cytosol. This then folds into a three-dimensional structure and may be further biochemically modified (post-transla-tional modification) to produce a protein (Figure 20.18). 

The third advance resulted from Francis Crick s reasoning on how the genetic information encoded in the 4-letter language of nucleic acids could be translated into... 

Proteins are the most abundant of cellular components. They include enzymes, antibodies, hormones, transport molecules, and even components for the cytoskeleton of the cell itself. Proteins are also informational macromolecules, the ultimate heirs of the genetic information encoded in the sequence of nucleotide bases within the chromosomes. Structurally and functionally, they are the most diverse and dynamic of molecules and play key roles in nearly every biological process. Proteins are complex macromolecules with exquisite specificity each is a specialized player in the orchestrated activity of the cell. Together they tear down... 

Proteins are informational macromolecules, the ultimate heirs of the genetic information encoded in the sequence of nucleotide bases within the chromosomes. Each protein is composed of one or more polypeptide chains, and each peptide chain is a linear polymer of amino acids. The order of the amino acids commonly found in the polypeptide chain is determined by the order of nucleotides in the corresponding messenger RNA template. In this chapter we examine four aspects of protein metabolism (fig. 29.1) (1) The process whereby amino acids are ordered and polymerized into polypeptide chains (2) posttranslational alterations in polypeptides, which occur after they are assembled on the ribosome (3) the targeting process whereby proteins move from their site of synthesis to their sites of function and (4) the proteolytic reactions that result in the return of proteins to their starting material, amino acids. 

Genotype. The genetic information encoded in the genome of an organism. Literally, it is the type of genome. 

Immunization of plants via priming for expression of latent genetic information encoding disease resistance mechanisms may be... 

The process of synthesizing RNA from the genetic information encoded by DNA is called transcription. The enzymes involved in transcription are called RNA pol)unerases. Prokaryotes have one type eukaryotes have three types of nuclear RNA polymerases. 

The genetic information encoded in DNA becomes functionally meaningful only when it is accurately transcribed and translated into RNA and protein. Two types of RNA, transfer (t) RNA and ribosomal (r) RNA, are themselves functional... 

The major path for extracting different information from the same pre-mRNA uses alternative splicing. The genetic information encoding a protein in higher eucaryotes is usually found in pieces of coding sequences, or exons, interrupted by non-coding sequences, the introns. For the formation of the mature mRNA, the introns must be... 

The genetic information encoded into the structure of nucleic acids is used to direct the assembly of amino acids in polypeptides. In a process called gene expression, genes are switched on and off so that living cells can conserve resources and respond to environmental or developmental cues. 

Protein synthesis is an extraordinarily complex process in which genetic information encoded in the nucleic acids is translated into the 20 amino acid alphabet of polypeptides. In addition to translation (the mechanism by which a nucleotide base sequence directs the polymerization of amino acids), protein synthesis can also be considered to include the processes of posttranslational modification and targeting. Posttranslational modification consists of chemical alterations cells use to prepare polypeptides for their functional roles. Several modifications assist in targeting, which directs newly synthesized molecules to a specific intracellular or extracellular location. 

The tRNAs serve as the molecular adaptors that read the genetic information encoded within the mRNA strand. 

The genome of a cell consists of all its genetic information, encoded in DNA (deoxyribonucleic acid). In eukaryotes, DNA is located mainly in nuclei, but small amounts are also found in mitochondria. Nuclear genes are packaged in chromosomes that contain DNA and protein in tightly coiled structures (Chapter 12). 

Primary structure the sequence of amino acids in the polypeptide chain (see Figure 1.3). This is unique to each protein, and is determined (primarily) by the genetic information encoded in the DNA of the relevant gene. 

This plays major roles in the transmission and regulation of the genetic information encoded by DNA. It contains ribose instead of deoxyribose (Fig. 3-27). 

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