1. Protein synthesis is important because the body uses proteins to build itself and to control itself.
     A: List 3 structures composed of protein.
     B: List 2 processes controlled by proteins.

2. Which scientist is being described below?
     …………… A: While working with bacteria discovered it was easy to change harmless                                   bacteria to harmful bacteria
     …………… B: Discovered that DNA was capable of changing organisms such as bacteria
     …………… C: Said that hereditary factors are located on chromosomes

3. What does the acronym DNA stand for?

4. The structure of DNA is surprisingly complex. Discoveries into its final form occurred in steps        over many years.
     A: One of the first discoveries was that DNA was composed of 4 bases called:
          (1)…………..…….. & (2)……………….. & (3)………………… & (4)…….…………
     B: Shortly afterwards it was determined that the amount of base A always equals the amount of           base (1)……., while the amount of base C always equals the amount of base (2)………
     C: Next is was discovered that the smallest section of a DNA molecule that can still be           considered DNA is called a nucleotide. One DNA nucleotide consists of 1 Five Carbon           (1)……………. + 1 (2)………………… group + 1 (3)…………. base.
     D: Finally 2 scientists called (1)………………….. & (2)…………………… determined that           DNA consists of a double-(3)……………., in which the rungs (sides) are composed of           alternating (4)……………………… & (5)……………………., and in which the steps are           composed of 2 (6)………………………………. held together by a weak (7)……………           bond.

5. To serve as the genetic code for any organism, a DNA molecule must be capable of storing large        amounts of varying information. How does the structure of a DNA molecule help it store large        amounts of information?

6. To serve as the genetic code for any organism, a DNA molecule must also be capable of copying        itself.
     A: When does a cell need to proceed with DNA replication?
     B: The process of DNA replication begins when the weak (1)………….. bond breaks, allowing           the DNA molecule to (2)……………………. down the middle of its entire length resulting           in 2 open strands. Immediately new (3)…………….bases attach to each open strand of           DNA, with (4)……….. always attaching to T and (5)…………. always attaching to G.           Finally the 2 newly formed DNA strands zip back up and recoil to form 2 identical DNA           double-(6)……………….. .

7. What does the acronym RNA stand for?

8. RNA differs from DNA since it uses a (1)…………….... sugar and (2)……………. nitrogen        base to make a (3)……………….. stranded molecule.

9. All living things on earth contain three types of RNA. (1)…………… is used to build ribosomes,        while (2)…………… is used to carry information from the DNA to the ribosome, and        (3)…………… is used to carry amino acids to where they are needed.

10. An essential step in the process of protein synthesis is transcription of the DNA code to mRNA.
     A: Transcription begins in the (1)…………….. of the cell where the DNA is located and ends           when the mRNA reaches an organelle called the (2)………………. .
     B: The process of transcription begins when a section of DNA called a (1)……………. unzips           and allows a single strand of (2)…………. to form along it. The process of unzipping the           DNA is controlled by an enzyme called (3)………………… . The mRNA strand that is           produced is a (4)……………………. copy of the original DNA.

11. A codon is a specific group of (1)….. nitrogen bases on a (2)………. molecule. There are        (3)……. different codons. Each of these codons attracts a specific (4)………………… .

12. An essential step in the process of protein synthesis is translation of the mRNA codon into a        functioning protein.
     A: Translation occurs in the (1)……………. of the cell and requires the presence of (2)……..            common amino acids.
     B: Translation begins when a ribosome begins to move along a (1)………….. to read its           codons. As each codon is read it attracts a specific (2)………… which brings a specific           amino acid with it. Once these amino acids line up near each other they are connected to           each other by a (3)……………….. bond. This finished chain of amino acids is called a           (4)………………… .

SUMMARY:
13. REPLICATION
   A: Complete the nitrogen base sequence for the new DNA.

   B: When does replication occur?
   C: Where does replication occur?
   D: What is the name for each set of 3 nitrogen bases?
   E: The new DNA is how many nucleotides long?
   F: Why is replication necessary?

14. TRANSCRIPTION
   A: Complete the nitrogen base sequence for the new mRNA.

   B: Where does transcription occur?
   C: What is the function of the mRNA?
   D: 1) List 3 structural differences between DNA and mRNA.
        2) Which one of the above structural differences is most
              essential for mRNA to be able to accomplish its task?
   E: Transcription plays an important role in the synthesis of
           what?
   F: What is the name for each set of 3 nitrogen bases?

15. TRANSLATION
   A: Complete the nitrogen base sequence for tRNA's
           #1, #2, and #3.

   B: Where does translation occur?
   C: What is the function of tRNA?
   D: What is the name of each set of 3 nitrogen bases
            on tRNA?
   E: What is formed when the amino acids are
            connected properly?
   F: Where does the tRNA find the necessary amino acids?
   G: What happens to tRNA after it releases its amino acids?

Critical Thinking Questions:
16. Why do proteins differ between species?
17. Proteins do differ between humans.
     a) Explain why.
     b) How does this affect man's goal of increasing organ transplants in the future?
     c) What group of people might have the highest rate of success with organ transplants?
18. To build a protein 500 amino acids long requires _____ DNA nucleotides, _____ mRNA        nucleotides, and _____ tRNA.
19. From where does your body obtain new nitrogen bases and amino acids?
20. All of the different proteins in your body are made from 20 different amino acids.
     a) Why was a system of 3 bases per codon required to code for these 20 amino acids?
     b) Why couldn't a system with 2 bases per codon work to code all 20 amino acids?
          (Hint - How many combinations of paired letters are possible using only 2 letters?)
21. What does the knowledge that mitochondria and chloroplasts have their own DNA lead        scientists to believe about their pasts?