Protein Synthesis: Transcription & Translation

 

 

Your goal in this activity is to review the process of protein synthesis that we worked on in class. It is a detailed process, but as you do the work and when you complete the work, step back and think about the big picture of what is happening. When you are done you should be able to answer the simple question of why this is an important process. What is the importance of this process to living things? What can happen if things go wrong with this process? What affect can the environment have on the process? What is the relationship between protein synthesis and evolution?

I have provided you with a number of websites to use to complete this packet. You may also conduct your own Internet search for your answers. If you find a good site which I did not mention, please share it with me for future use.

First let's review the molecules that are involved in protein synthesis.

I. Click on the DNA link beneath the structure above and find the answers to the following questions:

1. The three major parts of the DNA molecule are ____________________,

____________________ and _____________________.

2. The ____________________ and ____________________ make up the "backbone” of the molecule which can also be described as the two side poles if you think of the molecule as ladder-shaped.

3. The part of the molecule which designates the actual code is the sequence or order of the ___________________.

4. The four types of nitrogenous bases found in DNA are __________________,

__________________, __________________, and __________________.

5. The bases are connected to form the “rungs” of the ladder in the center of the molecule. The bases are held together by ________________________.

6. The nitrogenous bases can only bond together to form basepairs in the following way:

__________________ binds with__________________ and

__________________ binds with__________________.

II. Click on the RNA link beneath the structure above and find the answers to these questions:

1.  What are the differences between the RNA molecule and the DNA molecule?

a) _________________________________________________________

b) _________________________________________________________

c)  __________________________________________________________

2.  Name the three types of RNA and the function of each:

a)  ____________ ____________________________________________

b) ____________ ____________________________________________

c)  ____________ ____________________________________________

III. Click on the Protein link beneath the diagram above. Scroll down to the section on proteins and find the answers to the following questions.

1. Proteins are made up of long chains of ________________________.

2. How many different types of the molecule named in the question above are there? _______.

3. Name 3-4 important functions of proteins:

a) _____________________________________________________________

b) _____________________________________________________________

c) _____________________________________________________________

d) _____________________________________________________________

Now that you've reviewed the molecules involved in protein synthesis, let's get to the actual process.

First, look at this animation of the whole process:

http://www.wisc-online.com/objects/index_tj.asp?objid=AP1302

Then, use the following links to find the answers to the questions about protein synthesis:

http://www.pbs.org/wgbh/aso/tryit/dna/index.html

http://gslc.genetics.utah.edu/units/basics/transcribe/

http://www.accessexcellence.org/RC/VL/GG/protein_synthesis.html

http://en.wikipedia.org/wiki/Protein_biosynthesis

http://www.lewport.wnyric.org/jwanamaker/animations/Protein%20Synthesis%20-%20long.html

The process of protein synthesis can be broken down into two major steps:

I. Step One is called Transcription

 1. Define transcription.

 

2. Step one occurs in the section of the cell called the ____________.

3. A portion of the DNA molecule that carries a gene sequence ______________ and ______________, exposing the nitrogenous bases that carry the gene sequence or code.

4. A polymerase enzyme attaches to the DNA and makes a(an) __________ copy of the DNA gene sequence.

5. This new messenger molecule, carrying the gene code, exits the nucleus and goes out to the _______________ area of the cell.

II. Step Two is called Translation:

1. Define translation.

 

2. The mRNA attaches to a _________________ in the cytoplasm.

3. Sets of ______ nucleotides in the mRNA are called a codon or triplet codon.

4. Every codon can bind to only one ________molecule, which carries a specific ________________ to the site of synthesis where the mRNA is attached to the ribosome.

5. The first codon is called the _________ codon and its sequence is _______.

6. The final codon is called the ________ codon and its sequence can be__________, __________ or ___________.

7. The chain of amino acids that forms will ultimately fold up to form its final product, a ______________.

Finally, answer the following questions to demonstrate that you understand the big picture:

Use these web links to find answers to the questions below:

http://www.genetichealth.com/G101_Changes_in_DNA.shtml

http://gslc.genetics.utah.edu/units/disorders/sloozeworm/mutationbg.cfm

1. What do we call it when a mistake occurs in the sequence of the DNA nucleotides?

2. Why do mistakes occur? What are some causes?

 

 

3. When there is a mistake in the DNA sequence, what are the possible affects on its protein product?

 

 

 

 

4. When we study the theory of evolution in a few weeks, you will learn about how changes occur in species over time. When changes do occur, they may be beneficial or harmful to an organism's ability to survive. Based on what you've learned about the process of protein synthesis, how can it be a mechanism of change for a species? Write a short essay describing the relationship between mutations and changes in species over time (i.e. evolution). (Please word process your essay and attach it to this packet).