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Review: DNA & Protein Synthesis

Learning Target:Identify which key ideas about DNA and protein synthesis you still need to understand better

1. How many base pairs are there in a complete set of DNA? What percent of your DNA is identical to every other person’s on the planet?

• 3 billion (3,000,000,000)• 99.9%

2. Explain what each of the following is and why it is important to making proteins.

a. DNA

b. Gene

c. Chromosome

Molecule that contains genetic information. Holds all information for making proteins.

Section of DNA. Holds code for making one protein.

Bundle of DNA. How DNA is stored in nucleus.

2. Explain what each of the following is and why it is important to making proteins.

d. Amino acid

e. Ribosome

Molecule that makes up proteins.

Part of cell that joins amino acids together to make proteins.

Amino acidprotein

3. Identify 3 different ways living things depend on proteins.

• Building materials for muscle, skin, bone.

• Help fight infections as antibodies• Digest food as enzymes• Help control what goes in and out of

cell through cell membranes.

4. Draw a section of DNA that shows its double helix shape. Label four different nucleotide bases, showing which ones pair with which.

A G C T

T CG

A

5. Draw a simple diagram of a cell and label the following: nucleus, cytoplasm, cell membrane, DNA.

6. Summarize the processes of transcription and translation in making proteins.

Transcription = Making copy of one section of DNA (gene) in the form of mRNA.

Translation = Decoding mRNA to join amino acids together to make proteins.

7. What is the role of messenger RNA (mRNA) in protein synthesis?

Copy of DNA section that can go out of the nucleus into the cytoplasm, where proteins are made.

Carries message of DNA out of nucleus

8. What is the role of transfer RNA (tRNA) in protein synthesis?

Transfers amino acid molecules to mRNA, where they’re joined together to make proteins.

Amino acids

9. If a DNA strand has a base sequence of ATTGCCCA, what would the base sequence be on the opposite strand?

A T T G C C C A

T A A C GG

G T

9. What would the base sequence be on a strand of mRNA made from the ATTGCCCA base sequence?

A T T G C C C A

U

T A A C G G G T

A A CGGGU

m

10. Explain how changing one DNA base pair would affect protein synthesis.

Changing one base pair changes an amino acid, which changes the protein. T

Tay Sachs Disease

Protein shape makes a difference

11. Use the chart on p.303 of your text to write the amino acid sequence resulting from the following mRNA strand:

AAGUCCGUAUAG

AAG = LysineUCC = SerineGUA = ValineUAG = Stop

Video: DNA and Protein Synthesis

http://www.youtube.com/watch?v=nHM4UUVHPQM

http://ed.ted.com/lessons/the-twisting-tale-of-dna-judith-hauck

Questions?

What causes mutations?

• Exposure to radiation (x rays)• Exposure to chemicals

External factors:

What causes mutations?

• Mistakes in copying DNA

Internal factors: