 What is a genome?
 A genome is an organism’s full collection of genes.
 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.
 Define an operon.
 An operon is a group of genes that code for functionally
related protein in a prokaryotic cell.
 Explain the function of the following parts to the lac
operon.
 Promoter: Area on an operon where RNA polymerase
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attaches
Repressor: Attaches to operator and blocks movement of
RNA polymerase to structural genes
Operator: Area where repressor attaches. On/off switch
RNA polymerase: Attaches to promoter and transcribes
structural genes to make a lactase enzyme
Structural genes: DNA that codes for lactase enzyme
 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.
 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.
 Explain the roles of the following enzymes
 Restriction enzymes: Enzymes that cut specific regions
of DNA (“restricted” because can only cut in specific
region) Biological scissors.
 DNA ligase: Joins pieces of DNA together (glue)
 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.
 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.
 What are the steps in gel electrophoresis?
 DNA is cut by restriction enzymes to VNTRs.
 DNA samples are added to chamber wells
 Electrical current is added to move DNA through gel (DNA
is negative, end of gel is positive)
 DNA is transferred to a membrane with probes
 Gel is exposed to X-rays
 List the steps of PCR.
 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.
 Sample is cooled down and primers are added to
segments in order for DNA polymerase to attach to
strands.
 DNA polymerase attaches to primers and adds free
nucleotides to DNA strands.
 DNA ligase binds strands together and process repeats.
 How does gel electrophoresis organize DNA segments?
 Gel electrophoresis organizes DNA segments by their
size.
 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.
 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.
 List the steps in cloning an organism.
 The nucleus of an egg cell is extracted.
 The cell containing the DNA desired to be cloned gets
fused to egg cell by electric shock.
 The fused cell begins to grow and divide to an embryo
and is implanted into a female vector to carry the
clone.
 Why does the nucleus of the egg cell need to be
extracted in cloning?
 The egg cell does not contain the DNA desired to clone.
 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.
 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.