Transcript point mutation

Replication Protein
/Mutations Synthesis
DNA
Structure
DNA Control
Mechanisms
Biotechnology
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Question 1 - 10
What kind of mutation has occurred in the
following DNA sequences:
Original strand:
Mutated strand:
5’ ACT TGA CGA 3’
5’ ACT TGA GGA 3’
Answer 1 – 10
A point mutation (also called a substitution) has
occurred on the third set of nucleotides.
If we transcribed the DNA to RNA and then used
a codon chart, we could determine what kind
of point mutation it is: missense, nonsense, or
silent.
Question 1 - 20
What kind of mutation has occurred
in the following DNA sequences:
Original strand: 5’ ACT TGA CGA 3’
Mutated strand: 5’ ACT TGA CCG A 3’
Answer 1 – 20
A frame-shift mutation has occurred;
specifically, an insertion (a base was added).
If a base was instead deleted, it would also be a type of
frame-shift mutation. They both drastically change
the code following the insertion or deletion. The
message goes from making biological sense to being
gibberish.
Question 1 - 30
There are three kinds of point mutations—name
them in the order given.
1. This point mutation causes the codon to
code for a different amino acid.
2. This point mutation causes the codon to
code for an early stop codon.
3. This mutation causes the no change to the
resulting amino acid.
Answer 1 – 30
By definition:
Number one is a missense point mutation.
Number two is a nonsense point mutation.
Number three is a silent point mutation.
Question 1 - 40
Which strand, A or B,
would be the
LAGGING strand.
A
B
Answer 1 – 40
Strand B would be the lagging strand.
Strand B would start where the replication fork
is and build antiparallel to the original strand,
from 5’ to 3’. As it does this, the DNA
continues to separate and then there is a gap
where polymerization has to start again. This
creates [Okazaki] fragments instead of one
continuous strand.
Question 1 - 50
In DNA replication, name the
4 enzymes that construct a
new complimentary DNA
strand, in the order of their
use.
Answer 1 – 50
1. DNA Helicase breaks the hydrogen bonds,
separating the two strands
2. Primase lays a RNA primer down where replication
will begin.
3. DNA Polymerase (III) adds new nucleotides in the
5’ to 3’ direction starting at the primer. (technically
DNA Polymerase (I) also replaces the primer with
DNA nucleotides as well)
4. DNA ligase binds the lagging strand fragments
together to make a continuous DNA molecule.
Question 2 - 10
Using your codon chart, determine
the amino acid sequence produced
by the following DNA sequence:
3’ TAC ACT 5’
Answer 2 – 10
3’ TAC ACT 5’
5’ AUG UGA 3’
MET-Stop
Question 2 - 20
Using your codon chart, determine the
amino acid sequence produced by
the following DNA sequence:
5’ GCG TAA 3’
Answer 2 – 20
DNA: 5’ GCG TAA 3’
----mRNA: 3’ CGC AUU 5’
This is the same as: 5’ UUA CGC 3’ which is:
Must be read 5’ to 3’
LEU-ARG
Question 2 - 30
Which number corresponds
to the following ribosomal
sites:
A site
1 2 3
E site
P site
Answer 2 – 30
A site = 3, you can see the tRNA bringing in a
new amino acid to be added to the chain
E site = 1, the tRNA without an amino acid
would be the tRNA molecule exiting
P site = 2, the polypeptide is being built here,
there are two amino acids bound together
Question 2 - 40
What would facilitate the folding of a
freshly translated protein if it were to
stay in the same cell it was created in?
What if it was to be exported from the
cell?
Answer in order.
Answer 2 – 40
Chaperonin facilitates the folding of proteins
that stay within the creator cell.
The Rough ER facilitates the folding of proteins
that are leaving the cell.
Question 2 - 50
List the three modifications that
must be made to the primary
mRNA transcript before it can
leave the nucleus.
Answer 2 – 50
1. Introns must be removed from the transcript
2. Addition of a 5’ cap
3. Addition of a poly-A tail containing 50-250
adenine based nucleotides
Question 3 - 10
If a DNA sample consists of 12
percent Adenine, what
percentages would the
remaining bases make up?
Answer 3 – 10
A= 12%, T= 12%, C= 38%, G = 38%
For you mathy folks:
A= 12. A=T, therefore T = 12
A + T + C + G = 100.
If A + T = 24, then C + G = 76
If C=G, then C= one half of 76.
C = 38, G = 38.
Question 3 - 20
C
B
A
Identify parts A, B,
and C, and state
what these three
things are called
together.
Answer 3 – 20
A- Phosphate group
B- 5 Carbon Sugar (Pentose Sugar, specifically deoxyribose)
C- Nitrogenous Base (this one happens to be adenine)
Together they are known as a NUCLEOTIDE.
Question 3 - 30
Organize the following items in order from
GREATEST to LEAST (use the numbers).
1. Atom
2. Chromosome
3. DNA
4. Gene
5. Genome
6. Nucleotide
Answer 3 – 30
The correct order is: 5 , 2, 3, 4, 6, 1
Your genome is all of your genetic material, it is
usually made of 46 chromosomes, if you are
human. These chromosomes are long strands
of DNA plus some other molecules that help it
wind. Each DNA molecule is made of many
genes. Each gene is made of many
nucleotides, and each nucleotide is made of
many atoms.
Question 3 - 40
What kind of sugar is used in
this nucleotide?
C
5’
4’
1’
3’
A
2’
B
Answer 3 – 40
Deoxyribose
There is no oxygen on the 2’ carbon. This is why
we call it DEoxy.
Question 3 - 50
What did Hershey and Chase use
Sulfur-35 and Phosphorus-32 to
do in their experiment?
What was their conclusion?
Answer 3 – 50
Sulfur-35 was used to label the protein coat of
the virus.
Phosphorus-32 was used to label the phosphate
backbone of DNA.
When future generations were checked, in the sulfur experiment
there was no sign of the radioactive isotope.
In the phosphorus experiment, the new generations were still
radioactive. This concluded that DNA, not protein, is the
molecule of heredity.
Question 4 - 10
Which part of the operon, when
acted upon by another molecule,
turns a gene “on” or “off?”
Answer 4 – 10
The operator is the area that can turns a gene
on or off by induction or repression.
Question 4 - 20
What is a molecule that causes a
repressor to unbind with the
operator called?
Answer 4 – 20
An inducer.
Question 4 - 30
What is a molecule that binds
with a repressor in order to
turn a gene “off” called?
Answer 4 – 30
A co-repressor.
Question 4 - 40
What is a moveable segment of DNA
that is capable of blocking
transcription of a gene called? (also
known as a “jumping” gene)
Answer 4 – 40
A transposon.
Question 4 - 50
Can transcription
occur given this
operon’s
current state?
Why or why
not?
Answer 4 – 50
No, because the operator is being inhibited by
the repressor molecule. RNA polymerase
cannot read the gene and create a mRNA
transcript.
Question 5 - 10
What is the name of the effort
that set out to map the entire
human genome called?
Answer 5 – 10
The Human Genome Project.
Question 5 - 20
What is the name of the proteins
that cut DNA into fragments at
very specific base sequences?
Answer 5 – 20
Restriction enzymes.
Question 5 - 30
Which base pair fragment would
travel farther, given the same
amount of time, in a gel
electrophoresis sample:
2000 base-pair fragment
10000 base-pair fragment
Answer 5 – 30
The 2000 base pair fragment.
It has less mass, and less length, making it easier
to navigate through the porous gel.
Question 5 - 40
Why do DNA fragments
move towards the
positive end of a gel
electrophoresis
chamber when an
elecrtical current is
sent through the
chamber?
Answer 5 – 40
Because DNA is a negatively charged
molecule. It is repelled by the negative
side and attracted to the positive side of
the chamber.
Question 5 - 50
How are human genes inserted
into plasmids to produce a
desired protein product?
Answer 5 – 50
1. Restriction enzymes are used to produce “sticky
ends” on the desired human gene AND the plasmid
2. The sticky ends allow the human gene to be
connected to the plasmid and then is introduced to
a bacteria sample
3. The bacteria are grown to create the desired
protein product
(Antibiotic resistance gene is also added to the plasmid to identify which bacterial cells
successfully took up the plasmid. Only the ones that take up this plasmid will
survive when exposed to antibiotics)
Final Jeopardy
• Make your wager!
• Calculate the rate of the following graph!