Decoding DNA: Conclusions

Essential Question:How do our cells determine who we are?

How do cells use DNA to make proteins?

Step 1: TranscriptionAdenine Cystosine GuanineThymine (DNA only)Uracil (RNA only)

mRNA

DNA

Step 2: Translation

1. Summarize the process of transcription in making proteins

A copy of one strand of DNA is made in the form of mRNA (messenger RNA).

Adenine (DNA and RNA)Cystosine (DNA and RNA)Guanine(DNA and RNA)Thymine (DNA only)Uracil (RNA only)

mRNA

DNA

2. What do you call a section of DNA that holds the information needed to make a particular protein?

gene

3. Why did you cut the toothpicks of your DNA molecule in half?

DNA has to be “unzipped” to make a copy of one strand

4. What did the black licorice strand (with marshmallows) represent? What is its purpose in protein synthesis?

• mRNA (messenger RNA)• Copy of DNA strand that

can go out of nucleus to make protein.

• Carries message.

5. Summarize the process of translation in making proteins.mRNA is translated into chains of amino acids that form proteins.

6. What does tRNA do? How was tRNA represented in this simulation? Transfers amino acids to mRNA, where they are

joined together to make proteins.

protein

6. What does tRNA do? How was tRNA represented in this simulation?

You

protein

7. What did the colored paper circles represent?

Amino acids

8. How many bases are needed to code for one amino acid?

3

anticodon

codon

9. Use a genetic chart like the one on p. 303 of your text to write in order the names of the four amino acids translated from the following mRNA strands: a. AUGCAUACUUUG

• Methionine• Histidine• Threonine• Leucine

9. Use a genetic chart like the one on p. 303 of your text to write in order the names of the four amino acids translated from the following mRNA strands:

b. ACCAAAUCUUAA

• Threonine• Lysine • Serine • Stop

10. Mutations are changes in DNA structure from something as simple as a change in one base pair to the loss of a whole section. Mutations happen naturally as “mistakes” made in the process of copying DNA. DNA can also be damaged by exposure to chemicals or radiation from one’s environment. Explain how changing one base (from an A to a G for example) in a cell’s DNA can affect protein synthesis.

Changing one base changes a 3-letter code, which changes the amino acid made from it. That changes the protein made.

G

Protein shape makes a difference

11. How are proteins needed for life? Describe at least 4 different ways.

• Make up skin, bone, muscle, etc.• Help fight infections• Help control what goes in and out of cells

through cell membrane• Help control rates of chemical reactions• Help transport oxygen in blood

Video: One little change can make a big difference……

“Cracking the Code of Life” 15:00-21:00