Production of proteins in the cell
genetic information is stored in DNA;
the gene is a fragment of DNA.
explain how on the basis of DNA produced proteins create certain characteristics of the body;
distinguish the terms genetic code and genetic information;
show how genetic information is stored in DNA;
describe genetic code.
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Proteins are made of amino acids that combine with each other in very long chains. Each protein is characterized by a specific number of amino acids and the order in which they are arranged. The function of protein in the body depends on the aminoacid composition. The type and order of amino acids is determined by the sequence of nucleotides in the gene.
The nucleotides that make up the gene are read in threes. One of the three nucleotides corresponds to one amino acid. The three nucleotides are the basic coding unit in the genetic code, called codoncodon.
The genetic code consists of 64 codons. 61 of them encode amino acids. One of them is a START codon. It determines the amino acid called methionine, from which the synthesis of each protein begins. Three other codons, are called STOP codons, they do not correspond to any amino acid. Their presence is a signal to stop protein production. Such a signal in the form of a codon is necessary because the genetic code contains no gaps or separating characters. If STOP codons did not exist, protein synthesis could go on forever.
Indicate all true statements.
- The proteins are made of amino acids connected in long chains.
- The number of amino acids and their order in the protein determines its properties.
- The type and order of amino acids in the protein depend on the order of nucleotides in the gene.
- Each nucleotide encodes information on one amino acid in the protein.
What does the term codon mean? Indicate the correct answer.
- a single nucleotide in the DNA sequence coding for one amino acid
- three consecutive nucleotides in the DNA sequence coding for one amino acid
- a single amino acid encoded by the appropriate nucleotide sequence
- an amino acid chain encoded by the appropriate nucleotide sequence
Summary
The genetic code is a way of recording information about the structure of proteins.
The genetic code is in threes, meaning that one amino acid is coded by three nucleotides called codons.
The gene contains information about the structure of a specific protein; the order of codons in the gene determines the order of amino acids in the protein.
The genetic code is universal; Genetic information is recorded in all organisms in the same way.
Explain the relationship between the gene, protein and body traits.
Keywords
codon, genetic code, nucleotides
Glossary
informacja genetyczna –- informacja o kolejności aminokwasów w białkach zakodowana w sekwencji nukleotydów DNA, mówiąca pośrednio o cechach organizmu; nośnikiem informacji genetycznej jest DNA
kod genetyczny – sposób zapisu informacji genetycznej w materiale genetycznym (DNA)
kodon – trójka kolejnych nukleotydów w sekwencji kwasu nukleinowego, kodująca jeden aminokwas
sekwencja nukleotydów – kolejność ułożenia nukleotydów w cząsteczce DNA