Unit VII Study Guide
I. Vocabulary Check
1. “Glue” used to bond DNA fragments together
2. Small, self-replicating chromosome separate from main chromosome in bacteria
3. Transfer of DNA using a viral vector
4. Produced by bacteria as protection against bacteriophage; cleaves DNA at specific sites
5. Disposable copy of a gene
6. Added to 3’ end of RNA transcript
7. Added to 5’ end of RNA transcript
8. Chromosomal mutation in which order of DNA nucleotides is altered
9. Highly compacted DNA; not expressed
10. Variations in a single nucleotide; used as markers in genetic testing
11. Proteins that bind to DNA based on charge attraction
12. Gene mutation; type of substitution mutation which results in a different amino acid
13. Delivers amino acids to ribosome
14. DNA that is more loosely folded, expressed
15. Uptake of DNA by bacteria from environment
16. First amino acid in synthesis of polypeptide
17. Cancer gene; produces proteins that accelerate cell cycle
18. Enzyme that pairs tRNA with amino acid
19. DNA reversed transcribed from mRNA; useful in human gene testing
20. Phenomena in which variation may occur in base pairing between 3rd nucleotide of codon-anticodon
21. Site of ribosome synthesis in eukaryotic cells
22. Used to study gene expression; slide containing single-stranded DNA segments representing certain genes
23. DNA in which foreign DNA has been inserted
24. Primary component of ribosomes; capable of enzymatic activity
25. Chromosomal mutation in which a piece of DNA is lost
26. Produced from exposure to certain restriction enzymes; DNA fragments containing single-stranded ends
27. Proteins responsible for recognizing, splicing out introns
28. Chromosomal mutation in which two non-homologous chromosomes exchange genetic information
29. Method used to identify particular DNA sequences; use of labeled probe following DNA electrophoresis
30. Sequence of three nucleotides in mRNA that code for an amino acid
31. Enzyme that catalyzes re-writing of RNA to DNA
32. Blocks translation by base pairing with mRNA
33. Site of translation
34. Gene mutation; type of point mutation in which there is an addition or deletion
35. Chromosomal mutation in which multiple copies of DNA sequences result
36. Sequence of three nucleotides in tRNA that base pair with sequence in mRNA
37. Repeating segments of DNA; number of repeats is inherited
38. Gene mutation; substitution point mutation which terminates translation
39. Technique used to separate molecules based on size; charge attraction is driving force
40. Type of gene in which mutation can lead to loss of ability for cell to slow down cell cycle; acts as recessive mutation
41. Procedure used to amplify DNA; requires heat-resistant polymerase
42. Producing an organism from diploid DNA of another
43. Group of RNA viruses that contain reverse transcriptase
A. aminoacyl t-RNA synthetase
B. anticodon
C. cDNA
D. codon
E. DNA ligase
F. deletion
G. duplication
H. euchromatin
I. frameshift
J. gel electrophoresis
K. guanine cap
L. heterochromatin
M. histones
N. inversion
O. methionine
P. microarray assay
Q. missense
R. mRNA
S. nonsense
T. nucleolus
U. oncogene
V. plasmid
W. poly A tail
X. polymerase chain reaction
Y. reciprocal translocation
Z. recombinant DNA
AA. reproductive cloning
BB. restriction enzymes
CC. retrovirus
DD. reverse transcriptase
EE. ribosome
FF. RNAi
GG. rRNA
HH. SNPs
II. snRNPs
JJ. Southern blotting
KK. sticky ends
LL. STRs
MM. transduction
NN. transformation
OO. tRNA
PP. tumor suppressor gene
QQ. wobble
II. Complete the following paragraph about gene expression in prokaryotes.
There are important similarities and differences in gene expression of eukaryotes versus prokaryotes. In transcription in all cells, the
enzyme, ______________________________ unzips the DNA, moving in a _____ to ______ direction. Nucleotides are moved in
according to ______________________ rules and __________ is synthesized in a _______ to ________ direction. While similar in
principle, there are also differences between prokaryotic transcription and eukaryotic transcription. First, in prokaryotes, the
__________________________ step which involves _________________________ ____________________________,
__________________________________________, and ____________________________________________________________ is
absent. Secondly, the absence of a _________________ in prokaryotic cells __________________ the total amount of time required for
transcription and translation combined. And a third important difference is the organization of genes in the prokaryotic chromosome.
Multiple genes required for a single metabolic pathway are organized together in groups known as ____________________. In addition to
the genes coding for necessary __________________ for a particular metabolic pathway, this includes the ____________________, the
binding site for the enzyme needed for transcription, and the _______________________, the on-off switch for the gene cluster. The
operator is “on” unless it is blocked by a ____________________, a ___________________ molecule coded for by the
_______________________________ gene, which is separate from the rest of the ______________. This gene is
_______________________________, meaning it is always expressed; but the ____________________________ protein it produces
may be synthesized in a(n) _______________________ form, meaning transcription will be blocked, or in a(n)
___________________________ form, meaning transcription can proceed. The _____________ operon is a(n)
______________________________ operon, meaning it is normally off. Its repressor is synthesized in a(n) _______________________
form, meaning it will fit into the __________________ and block transcription. However, when ___________________ is present, it
binds to the repressor and renders it ________________________, allowing transcription to proceed. A(n) ________________________
operon, on the other hand, is normally on. Therefore, its repressor is synthesized in a(n) _______________________ form. An example
is the _______ operon. When ____________________ is present in the cell due to over-production or availability from surrounding
environment, it binds to the repressor and changes its shape rendering it ___________________, and transcription is blocked.
Repressors are negative controls; there are also forms of positive control known as __________________________. An example is found
in the lac operon. A bacterium’s first choice for energy metabolism is _________________, so when it is present in the cell along with
lactose, lactose metabolism is inhibited. The enzyme, _________________________ has a ___________ affinity for the lac operon
promoter. When ______________________ concentration is high, the concentration of another molecule, cAMP, is ____________. As
_____________________ concentration decreases, cAMP concentration __________________, eventually resulting in activation of
___________. This activator binds to the DNA and enhances the affinity of _____________________________ for the promoter.
Assuming lactose is available, and the repressor is __________________, the ___________________ required for lactose metabolism
are synthesized.
III. Eukaryotic Gene Expression - Complete the following table:
Transcription
Template
Location
Molecules Involved
Enzymes Involved
Start Signal
Stop Signal
Product
Translation
IV. Regulation of Eukaryotic Gene Expression – Match each of the following mechanisms of regulation with the stage at which it acts.
mRNA breakdown
DNA packaging/modification
Cleavage/modification/activation
Degradation of protein
Addition of cap and tail
Transcription
Splicing
Translation
Exit from nuclear envelope
V. Complete the following paragraph about gene cloning.
The agent used for gene cloning is often a ___________________, a self-replicating piece of bacterial DNA. The first step in this process
is to create __________________________ DNA; that is, to insert the foreign DNA into the bacterial DNA. This is done by exposing the
DNA containing the gene of interest and the bacterial DNA to the same ________________________________ enzyme. Typically, an
enzyme is chosen that will create ______________________ ends. Following enzyme exposure and the addition of the glue,
_______________________, there are three possible outcomes. Some of the bacterial DNA pieces will simply re-join in their original
conformation; that will also occur with the DNA containing the gene of interest. However, some of the fragments of DNA will join together
such that the gene of interest becomes incorporated into the bacterial _________________. In order to identify which ________________
contain the gene of interest, a _________________________ gene must be used. An example is the lacZ gene which codes for an
enzyme needed in lactose metabolism. Colonies growing on agar containing lactose that can break it down are blue; those that cannot are
white. This represents a “________ of function” gene; the site where the _____________________ enzyme initially cleaves the bacterial
DNA is in the middle of this gene. If insertion of the foreign gene is successful, the lacZgene is interrupted and no longer functional.
Following _____________________ enzyme exposure, bacteria are then treated to trigger the uptake of the circular bacterial chromosome
in a process known as __________________________________. A second ________________________ gene is used; however, this
represents a “_______________ of function” gene. The circular piece of DNA contains a gene for ampicillin resistance. If bacteria take up
the circular chromosome, they will be _____________________ to ampicillin. Following treatment, the bacteria are plated on agar
containing ampicillin and lactose. Only bacteria that took up the _________________ will grow. In order to isolate bacteria containing
_______________ incorporated with the gene of interest, only ___________-colored colonies are selected, indicating the
_______________________ to metabolize lactose. In summary, any colony that grows on the selective medium
_______________________________________________________________________, and any colony on that medium that is colored
white ________________________________________________________________
__________________________________________________________________________________________________________.