DNA Review
Mr. Hefti – Pulaski Biology
We can think about the DNA sequence of a gene as a sentence made up entirely of three-letter words. In the
sequence, each three-letter word is a codon, specifying a single amino acid in a protein. Have a look at this
sentence:
Thesunwashotbuttheoldmandidnotgethishat.
If you were to split this sentence into individual three-letter words, you would probably read it like this:
The sun was hot but the old man did not get his hat.
This sentence represents a gene. Each letter corresponds to a nucleotide base, and each word represents a
codon. What if you shifted the three-letter "reading frame?" You would end up with
T hes unw ash otb utt heo ldm and idn otg eth ish at.
As you can see, it is no longer an understandable sentence. In the same way, only one three-letter reading
frame within a gene codes for the correct protein.
Across
2. the two sides of DNA held together by weak ____ bonds
5. always pairs with cytosine
6. where protein is assembled from the message on the RNA
7. the shape of DNA, double ____
9. process of copying DNA
13. composed of a sugar, a base, and a phosphate
14. sections of DNA that code for a trait
15. replaces thymine in RNA
The following DNA sample was taken from a volunteer snork. The DNA was then transcribed to its complimentary
RNA strand. Your job is to analyze the RNA sample and determine the phenotype (how the organism looks) based
on the sequence. AUG is a start codon, it signifies the beginning of a new gene. UAA is a stop codon and signifies
the end of a gene. The genes are in order from gene 1 to gene 9. Use the codon chart above.
Snuffle Snork
AUG | GUA UCU AAA | GUU CCU ACU GAA AAG | CUU CUC CUC CCC | GUU GCG GCU | CAU CAC| GUA UUU UAU | GUA AUU CUU CUG CCC ACA | GUU
GAC GAC GCA | UUC UCG GGU | AGA UAU UGU | UAA
☺What is this type
of diagram called?
☺What are the
☺What it the name of this
structures called?
☺What are the
lab technique?
markings called?
☺ What causes the DNA to
☺What are they
made out of?
separate?
☺Is this person a
☺ What moves faster:
boy or a girl?
small fragments or large
☺Do you see any
mutations?
fragments of DNA?
☺If so, circle it.
☺ Whodunit?
☺What kind of
mutation is it?