Translation DNA stands for deoxyribonucleic acid Both DNA
Translation
DNA stands for deoxyribonucleic acid. Both DNA and RNA are nucleic acids; long polymers of nucleotides.
The outside of the DNA is called the sugar-phosphate backbone. This gives the DNA its shape and structure.
The nitrogen bases are on the inside of the double helix. It is the sequence of nitrogen bases that carries information in DNA.
Each section of DNA that is used to make proteins is called a gene. Genes are sections of DNA on the chromosome that carry useful information. The complete set of DNA containing all of the genes is known as the genome.
Transcription occurs in cells to make copies of the information found in the DNA. The DNA unwinds and separates between the nitrogen bases to expose the nitrogen bases which carry the information.
Transcription Once the strands of DNA are separated, the enzyme RNA polymerase copies the information from the DNA to a newly made strand of RNA.
Important Fact: There are 3 primary types of RNA that are involved in making a protein. messenger RNA (m. RNA) transfer RNA (t. RNA) ribosomal RNA (r. RNA)
Transcription The m. RNA go into the cell and attaches to a ribosome. In eukaryotes, many proteins are made by ribosomes in the cell’s “protein factory”, the rough endoplasmic reticulum. Free Ribosome Nucleus Ribosomes in Endoplasmic Reticulum
Translation Once the m. RNA is attached to the ribosome, the information is used to build a protein according to the universal genetic code. Each set of 3 nitrogen bases is known as a codon. Each codon is translated into an amino acid in the protein.
The Genetic Code is common to all… Photo by André Karwath To the horse in his stall From the bug on the floor, ALL living things use the SAME genetic code! Photo by Belinda Hankins Miller
The transfer RNA (t. RNA) that can base pair to the codon enters the ribosome and attaches its amino acid to the growing protein.
Ribosomes are the organelle that direct the construction of proteins. They read the m. RNA and use amino acids provided by t. RNA to build proteins one amino acid at a time.
Golgi Apparatus Proteins which need to be modified and packaged are sent to a Golgi body in vesicles where lipids and sugars are often attached. Golgi body
Gene Expression Gene expression describes the process of using the information in the genes of DNA to make products in the cell. The expression of genes is a regulated process within cells.
Gene Expression The cell turns genes ON and OFF so that only certain genes in the cell are expressed. This regulates how genes are expressed during transcription. Expressed ON
Gene Expression The cell turns genes ON and OFF so that only certain genes in the cell are expressed. This regulates how genes are expressed during transcription. Unexpressed OFF No Products!
Gene Expression Cells can also regulate how a gene is expressed by altering the m. RNA before a protein is made. Cells splice the m. RNA into different combinations that produce different proteins. Diagram by Agathman
Gene Expression This controls the how genes are expressed during the process of translation. However, this specific process of regulating gene expression only happens in eukaryotic cells. Diagram by Agathman
Using the Codon Chart The codon chart allows us to decode an m. RNA sequence using the universal genetic code. Almost every amino acid has more than one codon. This prevents mutations from changing proteins.
What is one of the correct codons for each of the following amino acids? Proline CCU CCA CCC CCG Methionine AUG Serine UCU UCA AGU UCC UCG AGC Cysteine UGU UGC Alanine GCU GCA GCC GCG Arginine CGU CGA AGA CGC CGG AGG
Using the Codon Chart Translate the following segments of m. RNA into the correct amino acid sequence. 5’ C U G A C C U A C A U A 3’ leucine – threonine – tyrosine - isoleucine Hint: Put a line after every 3 rd letter so that it is easier to see the codons!
Using the Codon Chart Translate the following segments of m. RNA into the correct amino acid sequence. 5’ A U G G G U U G A U U U 3’ methionine – glycine – STOP Hint: Put a line after every 3 rd letter so that it is easier to see the codons!
Stop means There is NOT an t. RNA that attaches to these special codons. This causes the production of the protein to STOP, and the finished protein is released from the ribosome.
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