Gene Expression - Chapters 16, 17, and 18 (Submit #1 on Thursday 1/8, Hard Copy. Submit #2-7 on
Monday 1/12 and #8-16 on 1/22 via GoogleDocs)
The genome of an organism can be found in each of its cells. However, a given cell only expresses the
portion of the genome relevant to that cell’s function. DNA codes for both RNA and polypeptides. All
organisms regulate which genes are expressed, when they are expressed, and how often they are
expressed. The simplest examples of gene regulation are seen in the operons of
prokaryotes. Eukaryotes employ more sophisticated regulation strategies.
Learning Goals - Students will be able to…
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

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describe the structure of DNA and chromosomes
explain how DNA is replicated
describe how genes are expressed and how expression is regulated
explain how mutation can disrupt gene expression and the normal functioning of an organism
Vocabulary
Watson and Crick
Frederick Griffith
Hershey and Chase
double helix
DNA
thymine
adenine
cytosine
guanine
uracil
purine
pyrimidine
nucleotide
5’ and 3’
origin of replication
replication fork
helicase
single strand binding protein
topoisomerase
primer
primase
DNA polymerase
leading strand
lagging strand
Okazaki fragments
DNA ligase
mismatch repair
nuclease
nucleotide excision repair
telomeres
telomerase
chromatin
histone
nucleosome
heterochromatin
euchromatin
transcription
translation
mRNA
rRNA
tRNA
primary transcript
triplet code
template strand
codon
RNA polymerase
promoter
terminator
transcription unit
transcription factors
transcription initiation complex
RNA processing
poly-A tail
5’ cap
RNA splicing
intron
exon
splicesome
ribozyme
alternative RNA splicing
anticodon
aminoacyl-tRNA synthetases
wobble
P, A, and E sites
polyribosomes
signal peptide
signal-recognition particle (SRP)
point mutation
substitution
silent mutation
missense mutation
nonsense mutation
insertion
deletion
frameshift mutation
operator
inducible operon
repressible operon
repressor
corepressor
cAMP
differential gene expression
histone acetylation
DNA methylation
epigenetic inheritance
control elements
enhancers
alternative RNA splicing
proteasomes
miRNA
RNAi
siRNA
Analysis Questions
1.
Draw out a segment of DNA that contains the nucleotide sequence 3’ATTCGG5’. Include the
sugar-phosphate backbone and hydrogen bonds. See Figure 16.7b on page 309 for a template.
(Turn in your drawing in hard copy.)
2.
Describe the research findings of Frederick Griffith.
3.
Describe the research findings of Alfred Hershey and Martha Chase
4.
A biochemist isolates, purifies, and combines in a test tube a variety of molecules needed for
DNA replication. When she adds some DNA to the mixture, replication occurs, but each DNA
molecule consists of a normal strand paired with numerous segments of DNA a few hundred
nucleotides long. What has she probably left out of the mixture? Explain.
a. DNA polymerase
e. primase
b. DNA ligase
c. nucleotides
d. Okazaki fragments
5.
Why do DNA molecules get smaller after each round of replication?
6.
The template strand of a gene contains the sequence 3’TTCAGTCGT5’. Identify the
non-template sequence and mRNA sequence. Include the 3’ and 5’ directionality.
7.
Compare DNA polymerase and RNA polymerase. Discuss primers, the direction of synthesis,
and the type of nucleotides used.
8.
How can human cells make 75,000-100,000 different proteins, given there are about 20,000
human genes?
9.
Explain the phenomenon known as wobble.
10.
What two processes ensure that the correct amino acid is added to a growing polypeptide
chain?
11.
Which of the following mRNA sequences would code for Phe-Gly-Lys? Explain.
a.
b.
c.
d.
e.
5’UUUGGGAAA3’
5’GAACCCCTT3’
5’AAAACCTTT3’
5’CTTCGGGAA3’
5’AAACCCUUU3’
12.
Complete the following table:
Type of RNA
Function
mRNA
tRNA
rRNA
miRNA
siRNA
13.
How does binding of the trp corepressor and the lac inducer to their respective repressor
proteins alter repressor function and transcription in each case?
14.
What are control elements and enhancers? How are they involved in the regulation of gene
expression?
15.
Discuss the effect of histone acetylation and DNA methylation on gene expression.
16.
Once mRNA encoding a particular protein reaches the cytoplasm, what are four mechanisms
that can regulate the amount of the protein that is active in the cell?