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DNA Notes
Chapter 8
DNA- (Deoxyribose Nucleic Acid) Molecule shaped like a twisted
ladder made up of 6 main subparts.
Nucleotides- the subunits of DNA. Each sub unit is made of a
sugar and phosphate backbone and a nitrogen base, which attaches
itself to a complimentary nitrogen base. Draw them from page 231
A-T G-C
A (adenine) only bonds with T (thymine)
G (guanine) only bonds with C (cytosine)
Exercise: Finish this DNA sequence by writing in the
complimentary base to the one shown:
GCATTTTAAAGGCCTATCTAGCTAGCAT
CGTA
DNA replication
DNA “unzips” at the nitrogen bases and new nucleotides attach to
the two half DNA’s forming two new identical DNA structures.
Occurs using an enzyme called Helicase.
Exercise: Given the DNA sequence below show, in a three step
process, what happens during replication?
Step 1: ATGCCTGACAGTATCG
TACGGACTGTCATAGC
AGTATCG
Step 2: ATGCCTGAC
AGC
hydrogen bonds
(DNA starts to unzip,
complimentary
Bases attach)
TACGGACTG
TCG
TCATAGC
GCCTGACAGTATCG
CGGACTGTCATAGC
Step 3: AT
TA
GCCTGACAGTATCG
CGGACTGTCATAGC
RNA transcription
RNA- Ribo Nucleic Acid- similar to DNA but only half strand and
Thymine is replaced with Uracil so, the base pairs are A-U G-C
Transcription of RNA- DNA unwinds and Nucleotides attach to
the DNA with U replacing T and this new molecule unzips from
the DNA, which then reattaches to itself.
Exercise: Create a RNA strand from the DNA code given:
DNA STRAND ATGCCTGACAGTATCGTATCGG
RNA STRAND UACG
Protein production
1. DNA transcription to RNA,
2. RNA translates the message into a protein by
attaching the amino acids together into a long chain
according to a genetic code of bases called a codon.
Found on page 244 in your textbook.
Exercise: answer the following questions:
1. What is the start codon? (methionine is the amino
acid) _______
2. What are the 3 stop codons? _____, _____, ____.
3. Given the following sequence of RNA translate the
code into the protein it will create:
RNA code:AUGCAGUCAGAAUUACAUUUGUAG
Amino acid: MET- GLN- SER-
(Start codon)
When Finished create your own 30 amino acid chain protein by
1. Creating the DNA strand (Don’t forget your start and stop codons)
2. Transcribing the RNA
3. Translating the amino acids to make your protein