Transcription:Translation POGIL- Honors, Lecture notes of Biology

Download Transcription:Translation POGIL- Honors and more Lecture notes Biology in PDF only on Docsity! Gene Expression- Transcription & Translation Why? DNA is often referred to as a genetic blueprint. In the same way that blueprints contain the instructions for construction of a building, the DNA found inside the nuclei of cells contains the instructions for assembling a living organism. The DNA blueprint carries its instructions in the form of genes. In most cases the genes direct the production of a polypeptide, from which other more complex proteins, such as enzymes or hormones, may be constructed. So, what is the language of these instructions and how are they read and decoded by the cell organelles? This activity will focus on the decoding of genes in eukaryotic cells. Model 1- Transcription & Translation 1. Consider the eukaryotic cell in Model 1. a. Where in the cell does transcription take place? b. What is synthesized, or created, from DNA during transcription? c. DNA is a double stranded molecule. How would you describe the appearance of mRNA? d. Where does mRNA travel to after transcription? 2. Consider that DNA cannot leave the nucleus of a cell. mRNA, or messenger RNA can leave the nucleus. What do you think is the purpose of mRNA? Read This! Transcription is similar to DNA replication except that in mRNA, the base Thymine (T) is no longer used. Instead, the base Uracil (U) pairs with Adenine (A). See the example below: DNA sequence - C G A T C mRNA sequence - G C U A G Name: _________________________________________ Date: _____________________ Period: _______ Freshmen Biology- Honors TRANSCRIPTION TRANSLATION Model 2- Transcription (DNA to mRNA) 3. Consider Model 2. a. Complete the statement below to describe the base pairing rule for DNA.
   
   
   
   In
   DNA,
   Adenine
   (A)
   always
   pairs
   with
   __________
   (
   
   ),
   and
   Cytosine
   (C)
   always
   pairs
   with
   
   
   
   
   
   
   
   
   ___________
   (
   
   
   ).
    b. Fill in the missing bases of the double stranded DNA molecule. (see the three examples) c. Complete the statement below to describe the base pairing rule for mRNA.
   
   
   
   
   
   
   In
   mRNA,
   Adenine
   (A)
   always
   pairs
   with
   __________
   (
   
   ),
   and
   Cytosine
   (C)
   always
   pairs
   with
   
   
   
   
   
   
   
   
   
   ___________
   (
   
   
   ). d. Fill in the missing bases of the single stranded mRNA molecule using the bottom strand of DNA as the template. (see the three examples) This is the end of the first step of gene expression, transcription, now let’s take a closer look at the second step of gene expression, translation. 4. Consider the eukaryotic cell in Model 1. a. Where in the cell does translation take place? b. What cellular structures attaches to the mRNA in order to assemble proteins? Read This! The second step in decoding genetic messages is translation. The sequence of bases in mRNA is a set of instructions that originated in the nucleus. When a ribosome is attached to an mRNA sequence, codons, or groups of three bases, are read by the ribosome. Each codon specifies for a particular amino acid used to create a protein. Name: _________________________________________ Date: _____________________ Period: _______ Freshmen Biology- Honors DNA (double stranded) mRNA (single stranded) T A C A U G