The Central Dogma of Biology: DNA to Protein
5. in nucleus
6. transcription is the process by which the message in DNA is transferred into mRNA.
DNA is unable to leave the nucleus since it will be broken down by enzymes in the
cytoplasm so the master copy of the instructions must remain protected in the nucleus.
8 the mRNA codon is complimentary to a specific tRNA anticodon at the bottom of the
tRNA. Each tRNA carries a unique amino acid to the ribosome for polypeptide synthesis.
For example the mRNA codon AUG can only bind to the anticodon UAC. The tRNA with an
anticodon of UAC will only ever carry the amino acid Methionine
24. The structure is quaternary because numerous polypeptide chains are shown attached
together. Also, most proteins are not functional until they are at the 4th level of structure.
DNA template 1: Alzheimer’s - PSEN2 (gene) – Presenelin 2
mRNA: AUG CUC ACA UUC AUG GCC UCU GAC AGC GAG GAA GAA GUG UGU GAU
Amino acids: Met Leu Thr Phe Met Ala Ser Asp Ser Glu Glu Glu Val Cys Asp
One letter code: M L T F M A S D S E E E V C D
Note: on all the subsequent tables like the ones below I copy and paste word for word from
the website so I can determine when students are not putting the information into their own
words.
Medical Condition
What is it?
How common is it?
Symptoms
Alzheimer’s
Alzheimer disease is a degenerative disease of
the brain that causes dementia, which is a
gradual loss of memory, judgment, and ability
to function.
Alzheimer disease currently affects an
estimated 2.4 million to 4.5 million Americans
Memory loss, forgetfulness, as the disorder
progresses the forgetfulness begins to
interfere with daily functioning
What is the normal function of the gene?
*note: you will have to click on the gene name to
open another page
How does a mutation cause/ increase the
risk for the medical condition?
As the disorder progresses, some people with
Alzheimer disease experience personality and
behavioral changes and have trouble
interacting in a socially appropriate manner.
Other common symptoms include agitation,
restlessness, withdrawal, and loss of language
skills.
The PSEN2 gene provides instructions for
making a protein called presenilin 2. Presenilin 2
helps process proteins that transmit chemical
signals from the cell membrane into the nucleus.
Once in the nucleus, these signals turn on
(activate) genes that are important for cell
growth and maturation.
Presenilin 2 is best known for its role in
processing amyloid precursor protein, which is
found in the brain and other tissues. Research
suggests that presenilin 2 works together with
other enzymes to cut amyloid precursor protein
into smaller segments (peptides). One of these
peptides is called soluble amyloid precursor
protein (sAPP), and another is called amyloid
beta peptide.
These mutations appear to disrupt the
processing of amyloid precursor protein,
leading to the overproduction of amyloid beta
peptide. This protein fragment can build up in
the brain and form clumps called amyloid
plaques that are characteristic of Alzheimer
disease. A buildup of toxic amyloid beta
peptide and amyloid plaques may lead to the
death of neurons and the progressive signs
and symptoms of this disorder.
1q31-q42
What is the cytogenetic location of the
gene?
base pairs 227,058,272 to 227,083,803
What is the molecular location of the
gene?
Early onset = autosomal dominanat
How is it inherited?
DNA Template 2: Parkinson’s – SNCA (gene) Synuclein
mRNA: AUG GAU GUA UUC AUG AAA GGA CUU UCA AAG GCC AAG GAG GGA GUU
Amino acids: Met ASP Val Phe Met Lys Gly Leu Ser Lys Ala Lys Ala Lys Glu Gly Val
One letter code: M D V F M K G L S K A K A K E G V
Medical Condition
What is it?
How common is it?
Symptoms
Parkinson’s Disease
Parkinson disease is a progressive disorder of
the nervous system. The disorder affects
several regions of the brain, especially an area
called the substantia nigra that controls
balance and movement.
Parkinson disease affects more than 1 million
people in North America and more than 4
million people worldwide. In the United
States, Parkinson disease occurs in
approximately 13 per 100,000 people, and
about 60,000 new cases are identified each
year.
Often the first symptom of Parkinson disease is
trembling or shaking (tremor) of a limb,
especially when the body is at rest. Typically, the
tremor begins on one side of the body, usually in
one hand. Tremors can also affect the arms, legs,
feet, and face. Other characteristic symptoms of
Parkinson disease include rigidity or stiffness of
the limbs and torso, slow movement
(bradykinesia) or an inability to move (akinesia),
and impaired balance and coordination (postural
instability). These symptoms worsen slowly over
time.
Parkinson disease can also affect emotions and
thinking ability (cognition). Some affected
individuals develop psychiatric conditions such
as depression and visual hallucinations. People
with Parkinson disease also have an increased
risk of developing dementia, which is a decline
in intellectual functions including judgment and
memory.
The SNCA gene provides instructions for
What is the normal function of the gene?
*note: you will have to click on the gene name to
open another page
How does a mutation cause/ increase the
risk for the medical condition?
making a small protein called alpha-synuclein.
Alpha-synuclein is abundant in the brain, and
smaller amounts are found in the heart, muscles,
and other tissues. In the brain, alpha-synuclein is
found mainly at the tips of nerve cells (neurons)
in specialized structures called presynaptic
terminals. Within these structures, alphasynuclein interacts with fats (lipids) and proteins.
Presynaptic terminals release chemical
messengers, called neurotransmitters, from
compartments known as synaptic vesicles. The
release of neurotransmitters relays signals
between neurons and is critical for normal brain
function.
Although the function of alpha-synuclein is not
well understood, studies suggest that it plays an
important role in maintaining a supply of
synaptic vesicles in presynaptic terminals. It may
also help regulate the release of dopamine, a type
of neurotransmitter that is critical for controlling
the start and stop of voluntary and involuntary
movements.
Researchers have described two types of alterations of the
SNCA gene in people with Parkinson disease. One type
changes a single protein building block (amino acid) used
to make alpha-synuclein. In some cases, the amino acid
alanine is replaced with the amino acid threonine at protein
position 53 (written as Ala53Thr) or with the amino acid
proline at position 30 (written as Ala30Pro). These
mutations cause the alpha-synuclein protein to take on an
incorrect 3-dimensional shape (misfold). In the other type
of alteration, one of the two SNCA genes in each cell is
inappropriately duplicated or triplicated. The extra copies
of the SNCA gene lead to an excess of alpha-synuclein.
It is unclear how alterations in the SNCA gene cause
Parkinson disease. This condition involves the selective
death or impairment of neurons that produce dopamine.
Misfolded or excess alpha-synuclein proteins may cluster
together (aggregate) and impair the function of these
neurons in specific regions of the brain. Aggregated alphasynuclein may disrupt the regulation of dopamine, which
allows dopamine to accumulate to toxic levels and
eventually kill neurons. Researchers also suspect that
misfolded or excess alpha-synuclein stalls or shuts down
the cell machinery that removes unneeded proteins. As a
result, unneeded proteins may clog neurons and impair
their functions. Symptoms of Parkinson disease appear
when dopamine-producing neurons become impaired or
die. The loss of these cells weakens communication
between the brain and muscles, and ultimately the brain
becomes unable to control muscle movement.
What is the cytogenetic location of the
gene?
4q21
base pairs 90,645,249 to 90,759,446
What is the molecular location of the
gene?
Many are not inherited but if it is autosomal
dominant
How is it inherited?
DNA Template 3: Breast Cancer – BRCA2 gene
mRNA: AUG CCU AUU GGA UCC AAA GAG AGG CCA ACU UUU UUG AAA UUU
Amino acids: Met Pro Iso Gly Ser Lys Glu Acid Arg Pro Thr Phe Leu Lys Phen
One Letter Code: M P I G S K E R P T F L K F
Breast Cancer
Medical Condition
What is it?
How common is it?
Symptoms
Breast cancer is a disease in which certain
cells in the breast become abnormal and
multiply without control or order to form a
tumor.
178,000 new cases of invasive breast cancer
will be diagnosed in U.S. women in 2007
Early breast cancer usually does not cause
pain and may exhibit no noticeable symptoms.
As the cancer progresses, signs and symptoms
can include a lump or thickening in or near
the breast; a change in the size or shape of the
breast; nipple discharge, tenderness, or
retraction (turning inward); and skin
What is the normal function of the gene?
*note: you will have to click on the gene name to
open another page
How does a mutation cause/ increase the
risk for the medical condition?
What is the cytogenetic location of the
gene?
irritation, dimpling, or scaliness.
The BRCA2 gene belongs to a class of genes
known as tumor suppressor genes. Like many
other tumor suppressors, the protein
produced from the BRCA2 gene helps prevent
cells from growing and dividing too rapidly or
in an uncontrolled way.
Researchers believe that the defective BRCA2
protein is unable to help repair damaged DNA
or fix mutations that occur in other genes. As
these defects accumulate, they can allow cells
to grow and divide uncontrollably and form a
tumor.
13q12.3
base pairs 32,889,616 to 32,973,808
What is the molecular location of the
gene?
How is it inherited?
Often not inherited but if it is = autosomal
dominant
DNA Template 4: Alzheimers APOE (gene) Apolipoprotein E
mRNA: AUG AAG GUU CUG UGG GCU GCG UUG CUG GUC ACA UUC
Amino acids: Met Lys Val Leu Trp Ala Leu Leu Val Thr Phe
One Letter Code: M K V L W A L L V T P
Medical Condition
Alzheimer’s
What is it?
How common is it?
Symptoms
What is the normal function of the gene?
*note: you will have to click on the gene name to
open another page
How does a mutation cause/ increase the
risk for the medical condition?
What is the cytogenetic location of the
Alzheimer disease is a degenerative disease of
the brain that causes dementia, which is a
gradual loss of memory, judgment, and ability
to function.
Alzheimer disease currently affects an
estimated 2.4 million to 4.5 million Americans
Memory loss, forgetfulness, as the disorder
progresses the forgetfulness begins to
interfere with daily functioning
As the disorder progresses, some people with
Alzheimer disease experience personality and
behavioral changes and have trouble
interacting in a socially appropriate manner.
Other common symptoms include agitation,
restlessness, withdrawal, and loss of language
skills.
The APOE gene provides instructions for
making a protein called apolipoprotein E. This
protein combines with fats (lipids) in the body
to form molecules called lipoproteins.
Lipoproteins are responsible for packaging
cholesterol and other fats and carrying them
through the bloodstream. Apolipoprotein E is
a major component of a specific type of
lipoprotein called very low-density
lipoproteins (VLDLs). VLDLs remove excess
cholesterol from the blood and carry it to the
liver for processing
It is not known how the APOE e4 allele is
related to the risk of Alzheimer disease.
However, researchers have found that this
allele is associated with an increased number
of protein clumps, called amyloid plaques, in
the brain tissue of affected people. A buildup
of toxic amyloid beta peptide and amyloid
plaques may lead to the death of neurons and
the progressive signs and symptoms of this
disorder.
19q13.2
gene?
What is the molecular location of the
gene?
45,409,038 to 45,412,649
When inherited = autosomal dominant
How is it inherited?