EXAM 3 Flashcards
Diabetes involves both genetic and environmental factors, yet one either develops the disease or doesn’t develop the disease, diabetes is an example of a multifactorial…
threshold trait
A trait like weight in people shows a…. distribution of phentoypes
continuous
The round pea shape in Mendel’s work is a good examples of a……
discontinuous (or single gene) trait
People with an inherited predisposition to retinoblastoma inherit …. defective alleles of the RB gene
one
The ability of cancer cells to move from the original tumor to a new site is called
metastasis
The major type of damage in DNA that is produced by UV light is
TT dimers
The principle cause of skin cancer is exposure to
sunlight
Fragile-X syndrome is an example of a disorder caused by what types of mutation
trinucleotide repeat
IF the phenotype of a trait is half due to genetics and half due to the environment, then the heritability of the trait is nearly
about 1/2
Small molecule released into synapses during nerve impulses are
neurotransmitters
In Huntington disease loss of neurons is due to the toxic effects of the
huntingtin protein
Most human behaviors are… traits that are influenced by both genetic and environmental factors
multifactoral
A neurological disease arising from high numbers of a CAG trinucleotide repeat is…
Huntington Disease
A gene whose enzyme produce is involved in the metabolism of neurotransmitters is
MAOA
If a pair of identical twins share a trait, then the trait is
concordant
If the heritability of the trait is near…. then the trait has almost no genetic component
zero
Viruses that cause cancer typically carry … as part of their genomes
oncogenes
What mutation in the ras proto-oncogene will change the gene to an oncogene and produce a RAS protein that differs from the normal gene by one amino acid
missense
The RB and p53 genes are good examples of … since they act to limit progression from G1 to S
tumor suppressor genes
A carcinogen and mutagen that is produced by fungal cells is
aflatoxin
Over the last 60 years the average IQ of children in the United States has steadily increased. What is a reasonable explanation for this trend?
The environment has changed in ways that increase the average IQ’s of the children
Our text discuessed examples of differential sensitivity among humans to drugs and chemicals in teh environment. What are four examples of these examples?
- The range of sensitivities found reflects differences in the nucleotide sequences of genes
- The range of sensitivities found reflects differences in the amino acid sequences of proteins
- The range of sensitivities found reflects differences in the active sites of proteins
- The range of sensitivities found reflects differences in genotypes
DNA rearrangements can dramatically change the expression of genes, what happens to the structure and expression of the c-abl oncogene after a reciprocal translocation generates the ‘Philadelphia Chromosome’ which is associated with a form of leukemia?
The c-abl gene is rearranged to form an active hybrid gene that is expressed in large amounts
What is a type of cancer commonly found in children?
leukemia
Most polygenic traits in people display:
a continuous distribution of the trait’s phenotype
When each of a pair of monozygotic twins exhibits the same trait, it is described as being
concordant
Sporadic retinoblastoma typically
occurs in one eye in adults
Traits where the phenotype depends on the effects of several genes as well as the environment are
multifactoral traits
The Concordance Value for cleft lip for monozygotic twins is 42% and for dizygotic 5%. What does this imply?
The environmental plays a major role in determining the trait
Traits that are determined by two or more genes are known as…
polygenic
For a multifactorial threshold trait like cleft lip, which group is expected to have the greatest ‘familial risk’ relative to the general population?
monozygotic twins
In humans, polygenic traits like weight or height exhibit
a continuous distribution of the phenotype
Mutant ras genes are associated with several forms of cancer. The normal, nonmutant ras gene
is a proto-oncogene
A defect in the X-linked monoamine oxidase type A gene is associated with mild mental retardation, aggression, and violent behavior. What may be true?
The trait is recessive and fewer females than males are affected
What are two things that may cause a predisposition to develop cancer?
- decreasing the expression of a tumor suppressor gene
2. decreasing the expression of a DNA repair gene
In twin studies of male homosexual behavior, if one brother showed homosexual behavior, then 52% of identical twins, 22% of nonidentical twins and 11% of unrelated adoptive brothers also showed homosexual behavior. What is this study consistent with?
There being significant genetic and environmental components to homosexual behavior
Schizophrenia may be related to problems with
producing the myelin membranes found on nerve cells
A human genetic disease that is associated with an increased number of trinucleotide repeats is
huntingtons disease
What enzyme is involved in the natural turnover of neurotransmitters?
monoamine oxidase
Which autosomal dominant trait is associated with progressive neurological decline which usually starts in middle age?
Huntington’s disease
A mutagen on DNA in skin cells, that doesn’t have the energy to mutate DNA in cells within the body, is
UV light
Ultraviolet light damages DNA by causing the formation of
thymine dimers in the DNA
The DNA in skin cells undergoes vast amounts of damage from sunlight. The usual result of this damage is
no effect on the overall cell metabolism because humans possess highly effective DNA repair systems
Metastasis refers to the process in which
tumor cells move to new sites in the body
The most aggressive form of skin cancer is
malignant melanoma
The Philadelphia chromosome was generated by
a translocation
A type of cancer involving over production of white blood cells is
lymphoma
What is associated with defective DNA repair?
an inherited predisposition to colon cancer involving the HNPCC1 gene
The heritability of the total ridge count in human fingerprints in nearly one. What does this imply?
A person’s genotype plays a much greater role than the environment in determining this trait
The principle cause of skin cancer is exposure to ….. in sunlight and tanning beds
UV-LIGHT
Which sex suffers the most from autoimmune diseases
females
The Philadephia Chromosome associated with myelogenuous leukemia involves which type of change to the normal human chromosome set?
translocation
The human papilloma virus is known to be a factor in the development of cancer of the
cervix
Dietary supplementation with … can significantly reduce the occurrence of spina bifida
folic acid
a ….. trait has a range of possible phenotypes but no separation of the members of a population into distinct phenotypic classes
continuous
Exposure to high levels of what gas is a factor associated with cancer of the lung
radon
the chemotherapy agent tamoxifen is converted to the active agent endoxifen which binds to the … receptors found on breast cancer cells
estrogen
The prehistoric distribution of the sickle cell anemia allele is related to the presence of
malaria
Transgenic mice with mutations in the gene required to produce … are a model for human obesity
leptin
Cocaine, heroin, and nicotine are all mimic the pleasure-associated neurotransmitter
endorphin
What syndrome is associated with frequent laughter and a smiling happy demeanor
angelmann
An example of a human trait affecting newborns that shows a threshold effect is
spine bifida
What disease result from the loss of neuron due to the toxic effects of a mutant protein
Huntington Disease
A defect in this X-linked gene is associated with aggressive behavior, violence, and incarceration
MAOA
For … traits the phenotype is determined by the effects of several genes as well as the environment
multifactorial
Inactivation of these gene leads to many new mutations in microsatellite repeats and is associated with colon cancer
HPNCC1
What genes encode proteins that act to prevent cells from moving from the G1 to the S stage of the cell cycle?
Tumor suppressor genes
If the heritability of a trait is nearly one, then an individual’s … plays the greatest role in determining the phenotype
genotype
Individuals who inherit a defective copy of the RB gene involved with retinoblastoma typically develop cancer in how many of their eyes in early childhood
two
Which of the following is associated with the most cases of inherited mental retardation where multiple member of a family over several generations are affected?
Fragile X syndrome
The Concordance Value for schizophrenia for monozygotic twins is 0.69 and that for dizygotic twins is 0.28; what does this imply?
Both genotype and environment play a role in determining the trait.
What is true of Fragile X syndrome?
The trait is an X-linked recessive and fewer females than males are affected
What is an example of a multifactorial trait?
skin color
The genetic basis of Huntington disease is
increased numbers of trinucleotide repeat that encodes a polyglutamine tract in the Htt protein
The best evidence that we have indicates that schizophrenia may be related to problems with
producing the myeline membranes found on nerve cells
intelligence and general cognitive ability is a multifactorial trait. The average IQ of children in the US has risen significantly over the last 50 years. On these standardized tests most minorities in this country average 10-15 points lower than the average score for whites. Considering what you know about multifactoral traits and human families, which of the following statements is a reasonable explanation for this trend?
changes in nutrition, schooling and social interactions have led to an increase in the average IQ’s of children
What proportion of the total number of breast cancers in the USA involves women who have inherited a BRCA1 mutation?
5%
The most significant behavioral and environmental factor associated with increased deaths due to cancer is
smoking
What is an example of an autoimmune disease that differs from other autoimmune diseases in that both women and men are almost equally likely to develop the disease?
diabetes
Identical twins have different fingerprints; this shows that development of fingerprints
is influenced by the uterine environment
Mutant ras genes are associated with several forms of cancer. The normal, nonmutant ras gene
is a proto-oncogene
Metastasis refers to the process in which
cells leave the original tumor and establish new tumors at other locations in the body
Traits that are determined by two or more genes are described as being
polygenic
Most carcinogens cause cells to become cancerous by
damaging the DNa and increasing the number of mutations that result when the damage is not repaired correctly
Given that they are living in the same environment, which of the following groups is expected to ave the broadest phenotypic range fora multifactorial trait?
the members of an ethnic group
When each of a pair of twins exhibits the same trait, it is described as being
concordant
What behavioral condition is associated with obsessive eating?
Prader-Willi Syndrome
Which common type of human cancer requires mutations at several different tumor suppressor genes and proto-oncogenes to have taken place
colon cancer
Most multifactorial traits show
a continuous distribution of the trait’s phenotype
The immune system cells that can destroy virus-infected cells are the
Killer T cells
One retrovirus that infects T4 helper cells is
HIV
Allergies are associated with which type of antibody?
IgE
How many different types of antigens can be recognized by the T cell receptor proteins on a single T cell
1
IgG antibodies contain two heavy chain protein subunits and … light chain protein subunits?
2
What type of antibody is a reagent produced by the biotechnological industry that interacts with high specificity to a single unique antigen within a protein
monoclonal
Replacement of an organ with one from another animal is an example of a
xenotransplant
In an emergency which bloody type can serve as a ‘universal donor’
Type O
Which cells does HIV infect?
Helper T4 cells
How many different types of antigens can be recognized by the proteins produced by a single B cell?
one
How many different types of protein chains are found in each IgG antibody?
two, one of each of the heavy and light chains
The cells that produce antibodies are the
activated B cells
The protein and sugar groups on pathogens that induce an immune response are
antigens
The enzyme that synthesizes DNA using an RNA template is
reverse transcriptase
The defense mechanism of the body that involves localized swelling, complement protein action, and engulfment of pathogens by macrophages is
inflammation
The proteins on T cells that recognize pathogens are the
T cell receptors
Where would you look in the body to find the stem cells that produce B and T cells?
the bone marrow
In hemolytic disease of the newborn the mother produces antibodies that lead to the destruction of the baby’s red blood cells when
the father is RH+, the mother is RH-, and the child is RH+
After reverse transcription the next step in a retroviral infection is
integration of a copy of the viral genome into a nuclear chromosome
The human cell surface receptor allele that provides partial resistance to infection by HIV is most abundant in the native populations found in
Northern Europe
In countering infections, the body’s first protection is by
the skin
The lifelong resistance to a disease that is set up by the immune system following a childhood vaccination or infection with a disease such as mumps is due to the generation of
populations of memory B and memory T cells
This severe reaction occurs when an allergic response, for instance to the antigens in bee stings or peanuts, triggers a sudden drop in blood pressure and difficulty in breathing
anaphylactic shock
The sleeping sickness parasite protects itself form the human immune system by
changing the antigens on its cell surface
The DNA rearrangements that are needed to construct functional immune system genes occur in the
heavy and light chain genes for making antibodies and the T cell receptor genes
In blood transfusions, individuals of blood type B have antibodies that will interact with
ABO antigens only on type A and on type AB blood cells
In organ transplants the recipient’s main immunological response is to
the HLA histocompatibility group antigens on the surface of the donor’s cells
What parts of an antibody molecule actually form the antigen-binding region?
the ‘variable’ regions of both the light and the heavy chain protein subunits
The major purpose of vaccination against a pathogen is to have the body produce
numerous memory B and T cells that will be able to respond to a later infection by the pathogen
Which ‘blood group’ proteins are involved in hemolytic disease of the newborn?
the Rh proteins
Which type of antibodies is the most abundant immunoglobulin in the blood and can pass through the placenta to the fetus from the mother’s bloodstream?
IgG
Differentiation of which types of cells involves the deletion of parts of the human genome?
B cells and T cells
Cancer cells are recognized and destroyed by
Killer ‘Cytotoxic’ T cells
In blood transfusions, individuals of blood type O
have antibodies that will interact with antigens on type A, type B, and type AB blood cells
In an adult the cells responsible for the rapid response to a second infection by a bacterial pathogen to which they had been exposed as a child are the
Memory B and T cells
Which type of antibodies is associated with allergies?
IgE
In terms of the number of molecules that they can bind to, how many different types of antibodies are produced by an individual cell in the immune system?
1
In organ transplants the recipient’s main immunological response is to
the HLA histocompatibility group antigens on the surface of the donor’s cells
SCID, a severe combined immunodeficiency, is associated with
a complete absence of both B cell and T cell mediated immune responses
