Gene Technology Quest – Study Guide KEY
1. What is a genome?
A genome is an organism’s full collection of genes.
2. Why do cells need to control gene expression?
Cells need to control gene expression because they only need to express genes
when necessary. This is to conserve energy and nucleotides.
3. Define an operon.
An operon is a group of genes that code for functionally related protein in a
prokaryotic cell.
4. Explain the function of the following parts to the lac operon.
a. Promoter: Area on an operon where RNA polymerase attaches
b. Repressor: Attaches to operator and blocks movement of RNA
polymerase to structural genes
c. Operator: Area where repressor attaches. On/off switch
d. RNA polymerase: Attaches to promoter and transcribes structural genes
to make a lactase enzyme
e. Structural genes: DNA that codes for lactase enzyme
5. When lactose is present what happens to the lac operon? Absent?
When lactose is present, the operon is on and the repressor protein is not
attached to the operator therefore RNA polymerase can attach to the
promoter and transcribe the RNA to make a lactase enzyme.
When lactose is absent, the operon is off and the repressor protein is attached
to the operator which blocks RNA polymerase from transcribing RNA.
6. What are the differences between introns and exons?
Introns are the noncoding portions of DNA and do not leave the nucleus. Exons
are coding regions of DNA and are transcribed and translated.
7. Explain the roles of the following enzymes
a. Restriction enzymes: Enzymes that cut specific regions of DNA
(“restricted” because can only cut in specific region) Biological scissors.
b. DNA ligase: Joins pieces of DNA together (glue)
8. What are sticky ends and what is their importance?
Sticky ends are the overhang of nucleotides that result when a restriction
enzyme cuts DNA. Their importance is that this allows for DNA from other
organisms to join this genome in order to make recombinant DNA.
9. How is recombinant DNA formed?
Recombinant DNA is formed when a restriction enzyme cuts the DNA from one
organism and DNA from another organism is added to the sticky ends of the
cut DNA. Once DNA ligase binds the two species DNA then the DNA is
recombinant.
10. What are plasmids? What is their function?
Plasmids are circular pieces of bacterial DNA, and their importance is that
they allow bacteria to code human protein.
11. List the steps of PCR.
1. The ingredients to make new DNA are added to PCR machine (DNA strands,
DNA polymerase, DNA ligase, primers, and free nucleotides) DNA is heated
in order to separate the strands.
2. Sample is cooled down and primers are added to segments in order for
DNA polymerase to attach to strands.
3. DNA polymerase attaches to primers and adds free nucleotides to DNA
strands.
4. DNA ligase binds strands together and process repeats.
12. How does gel electrophoresis organize DNA segments?
Gel electrophoresis organizes DNA segments by their size.
13. What determines how far a DNA segment can travel in electrophoresis?
Size and weight determine how far a DNA segments can travel in
electrophoresis. The smaller fragments move farther and faster through the
gel.
14. Why are VNTR sequences important for identification?
VNTR sequences are non-coding regions of DNA that are different to each
person. These are helping in identifying an individual because VNTR
sequences can create a bio fingerprint that is specific to only them.
15. List the steps in cloning an organism.
1. The nucleus of an egg cell is extracted.
2. The cell containing the DNA desired to be cloned gets fused to egg cell by
electric shock.
3. The fused cell begins to grow and divide to an embryo and is implanted
into a female vector to carry the clone.
16. What is the goal of the Human Genome Project?
The goal of the Human Genome Project is to create maps showing where genes
are located on human chromosomes.
17. What results from a vaccination?
A vaccination will result in a patient building immunity for the pathogen that
has been introduced to their body. The vaccine does not cause the disease, but
will create antibodies against it.
18. Explain how genetically modified foods are produced.
Genetically modified foods are produced by making recombinant DNA using
restriction enzymes. The enzyme will cut the DNA from one organism and add
the desired gene to the DNA segment. This is used in farming to help farmers
make their crops stronger or to incorporate vitamins/minerals into a crop. An
example would be a tomato plant with arctic flounder genes to withstand cold
temperatures or rice with Vitamin A genes.