Write the COMPLEMENTARY DNA strand for each sequence.

1. TACGGCAAACTTACT

2. TACGCCATT

3. TACAAAAAGTGGATC

DNA Replication Review

• Flash Tutorial

Learning Targets“I Can. . .”

-List three ways that RNA is different from DNA.

-List the three types of RNA.

-Describe the role of mRNA and tRNA during protein synthesis.

-Define “transcription” and where it occurs in the eukaryotic cell.

-Define “translation” and where it occurs in the eukaryotic cell.

Protein Synthesis

DNA RNA Protein

What is RNA? Ribonucleic Acid

1. Nucleotides

A G C U

ADENINE GUANINE CYTOSINE URACIL

What is RNA? Ribonucleic Acid

2. Contains the sugar ribose, rather than deoxyribose

3. Is single stranded, rather than double stranded

4. Three types:a. mRNA (Messenger)

b. tRNA (Transfer)

c. rRNA (Ribosomal)

Why do we have protein in our bodies?

1. Enzymes

2. Major component of the cell membrane

3. Structural component of skin and muscle

4. Basically, DNA codes for protein, which become you!

Recall: DNA is made of nucleotides strung together into a chain. These

nucleotides code for amino acids.

1. Amino acids: the subunits strung together in a protein chain

2. The four nucleotides are grouped into threes: these groups of three are called codons.

Recall: DNA is made of nucleotides strung together into a chain. These nucleotides

code for amino acids. 3. Each codon specifies a particular amino acid

that is to be placed in the protein PAGE 367

AAA = _________________

GGA = _________________

AUG = _________________

UAA = _________________

DNA RNA (Transcription)

1. Transcription: a molecule of DNA is copied into an opposite strand of mRNA

*Transcription occurs because DNA cannot leave the nucleus, and proteins are made outside the nucleus

DNA RNA (Transcription)

DNA RNA (Transcription)

2. Steps:

a. DNA strands are separated by an enzyme

b. An mRNA strand is created from the DNA strand to be copied (remember base-pairing rules except . . . )

*G with C

*A with U

DNA RNA (Transcription)

DNA = TACCGTTGCAACATT

mRNA =

RNA Protein (Translation)

RNA Protein (Translation)

1. Translation: the creation of a chain of amino acids from mRNA

mRNA = AUGGCAACGUUGUAA

Amino acids =

RNA Protein (Translation)

2. Translation requires tRNA, which carries amino acids and rRNA, which makes ribosomes

3. Ribosomes floating in the cytoplasm and attached to the ER are the location of protein translation

Alleles for diseases come from mutations

Mutations: mistakes made during DNA replication or protein synthesis1. Nucleotide substitution: TATGCA becomes TATTCA2. Nucleotide addition: TATGCA becomes TATGGCA3. Nucleotide deletion: TATGCA becomes TATCA

All produce frameshift mutations!

RNA Protein (Translation)

1. TACGGCAAACTTACT

DNA

mRNA

Protein

RNA Protein (Translation)

2. TACGCCATT

DNA

mRNA

Protein

RNA Protein (Translation)

3. TACAAAAAGTGGATC

DNA

mRNA

Protein

References

• http://www.safarikscience.org/biologyhome/7_dna/codon_question.png

• http://www.accessexcellence.org/AE/AEPC/WWC/1994/codon_bingo.php