Genetics Midterm
About ____ percent of all newborns are affected with an abnormal karyotype.
0.05
Twin, adoption, and family studies show that obesity has a heritability that averages close to ____.
0.7
In humans, hair texture is an incompletely dominant trait. Curly is the dominant genotype, wavy is heterozygous, and straight hair is recessive. What is the probable phenotypic ratio for a cross between a man with wavy hair and a woman with curly hair?
1/2 wavy hair; 1/2 curly hair
After contracting SARS, about ____ percent of the infected died.
10
According to Wilhelm Stern's method of measurement, a ten-year-old child who is able to perform the mental tasks of a ten-year-old (but not of an eleven-year old) has an IQ of ____.
100
The chemical formula for glucose, C6H12O6, represents ____ atom(s) and ____ molecule(s).
24;1
The chance of a child having albinism when both of his parents are heterozygous for the disorder is ____ percent.
25
Approximately ____ Y-linked genes have been discovered.
60
During meiosis in an organism where 2n = 8, how many chromatids will be present in a cell at the beginning of meiosis II?
8
What is the greatest risk factor for cancer?
Age
During the 1968 Olympic Games, the International Olympic Committee performed an analysis of ____ on all female athletes in order to verify their sex.
Barr bodies
DNA polymerase catalyzes the synthesis of ____.
DNA
A rare genetic disorder called Gaucher disease may strike as many as one in 450 people of ____ descent.
Eastern European
Genes are precisely copied during the process of DNA replication and never undergo any change.
False
Genetic discoveries made in one organism cannot necessarily be applied to other species.
False
Genetic modification of immune cells has not been shown to be an effective leukemia treatment.
False
In the years after the completion of the human genome project, genome sequencing revealed surprisingly little amount of variation in the sequence and arrangement of nucleotides in humans.
False
The Immigration Restriction Act of 1924 was supported by research that demonstrated that Western Europeans were genetically superior to Eastern Europeans.
False
The U.S. has stayed ahead of the issues surrounding genetic technology by implementing ground-breaking public policy and laws.
False
The phenotype of ____ does not develop until adulthood.
Huntington's disease
Each amino acid has a different side chain, called a(n) ____.
R group
In a cross between a true-breeding plant bearing the dominant traits of smooth, yellow seeds and a true-breeding plant bearing the recessive traits of wrinkled, green seeds, the offspring (F1) are all smooth and yellow and their genotype is ____.
SsYy
In some societies, the birth of a deformed child is regarded as a sign of impending war or famine.
True
Normal white blood cells (called B cells) and cancerous B cells that cause leukemia both carry a unique surface protein called CD-19.
True
The human genome carries approximately 20,000 genes.
True
The separation of genes during the formation of the sperm and egg and the reunion of genes at fertilization is explained by the behavior of chromosomes in a form of cell division called meiosis.
True
In the cell cycle, the G1 phase represents ____.
a period of growth
The process of meiosis results in ____.
a reduction in the chromosome number
The ____ model of genetic analysis of complex traits assumes that each gene involved has an equal effect on the phenotype.
additive
A fetus's exposure to ____ is the leading preventable cause of birth defects.
alchohol
If nondisjunction occurs during meiosis I, ____.
all gametes will be abnormal
Before Mendel, most people would have predicted that a cross of a red rose with a yellow rose would produce ____.
all orange roses
Alternate forms of a gene are called ____.
alleles
One gene is able to encode information for different forms of a protein via ____.
alternative splicing
The three-dimensional shape of a protein is determined by the ____ and the results of chemical modifications and other processing events.
amino acid sequence
Proteins are composed of subunits called ____ linked together by chemical bonds.
amino acids
In meiosis, homologous chromosomes separate in ____.
anaphase I
The nucleotide sequence encoded in a gene defines the ____ that make up proteins.
animo acids
Common recessive alleles present in a family can result in a pedigree that looks like ____ inheritance.
autosomal dominant
Almost all cases of cystic fibrosis, a(n) ____ genetic disorder, are the result of mating between two unaffected parents.
autosomal recessive
The DNA components adenine, thymine, guanine, and cytosine are examples of ____.
bases
Camptodactyly causes ____.
bend, immobile little fingers
Twins are concordant for a trait when ____.
both twins have the trait
The first genetic trait described in humans was ____.
brachydactyly
Macromolecules including sugars, glycogen, and starches composed of sugar monomers linked and cross-linked together are known as ____.
carbohydrates
The topic of ____, the idea of the fundamental unit of living organisms, raised several questions in Mendel's mind about inheritance.
cell theory
Teratogens affect the ____ more than any other part of the fetal body.
central nervous system
Spindle fibers attach to the ____ of a chromosome during cell division.
centromere
Activated genes can be inactivated by reversing histone modification during a process called ____.
chromatin remodeling
The pathway from ____ sex to ____ sex can be disrupted at several stages.
chromosomal; phenotypic
The gene responsible for Marfan syndrome encodes a protein associated with ____.
connective tissue
Autism, Alzheimer disease, Parkinson's disease, and schizophrenia are all associated with ____.
copy number variants
A deletion in the short arm of chromosome 5 is associated with ____ syndrome, which causes intellectual disability, defects in facial development, and an abnormal larynx.
cri du chat
If two phenotypically normal parents have six children, and two daughters and two sons have the same genetic disorder, that disorder is most likely to be ____.
cystic fibrosis
Hereditarianism is the idea that all human traits are ____.
determined only by genes
A zygote is a(n) ____.
diploid cell
Most triploid zygotes probably arise from ____.
dispermy
The inner lining of the uterus that is shed at menstruation if fertilization has not occurred is called the ____.
endometrium
The part of the male reproductive system where sperm mature is known as the ____.
epididymis
Mitosis is a process that is unique to humans.
false
Primary oocytes and spermatogonia are both haploid cells.
false
Teratogenic effects of alcohol only occur during the first 12 weeks of pregnancy.
false
The four macromolecules making up our cells allow for the same structure and function across all cells in the body.
false
A blood test cannot determine if a person is a carrier of Tay-Sachs disease because the mutant allele is undetectable.
false
A pedigree is always able to provide enough information to rule out all but one possible pattern of inheritance.
false
Amniocentesis is not performed on mothers over the age of thirty-five.
false
Because RNA is single-stranded, it does not participate in the regulation of gene expression.
false
Because females carry two X chromosomes and males carry only one, females have higher levels of all products encoded by genes on the X chromosome.
false
Bruce Reimer was born with ambiguous genitalia.
false
Chi-square tests are used to determine whether a cross has been correctly constructed and analyzed.
false
Chromosomes are usually studied and photographed while they are in anaphase of mitosis.
false
Cytokinesis usually occurs just prior to mitosis.
false
DNA contains two identical polynucleotide chains.
false
Each amino acid is encoded by only one mRNA codon.
false
Epigenetic modifications affect the nucleotide sequence of the DNA.
false
Gregor Mendel was a completely self-trained scientist and never attended university.
false
Human traits are controlled only by the genetic material found in the 46 chromosomes.
false
In June 2013, the U.S. Supreme Court ruled that if a gene is removed from the human body and purified it can be patented.
false
In the early twentieth century, most scientists believed that only nucleic acids were complex enough to carry genetic information.
false
Mendel chose to study pea plants because they have a long life cycle that offers ample time for analysis.
false
Mitotic divisions reduce the number of chromosomes found in daughter cells.
false
Most of those affected with an autosomal dominant genetic disorder are homozygous for that trait.
false
People with albinism carry two copies of the dominant allele (AA) and cannot make a pigment called melanin.
false
Phenotypic sex is determined at the moment of fertilization.
false
Phenotypic variation among individuals with the same genotype is known as genetic variance.
false
Random assortment occurs between chromatids of homologous chromosome pairs.
false
Submetacentric describes a chromosome whose telomeres are attached to the centromeres.
false
The additive model for polygenic inheritance proposes that the genes controlling a trait are all on one chromosome.
false
The brain and nervous system of a developing embryo can only be damaged during the very early stages of development.
false
The contributions of genes and environmental factors are strictly defined during the study of complex traits.
false
The set of proteins in a particular cell type is always equal to the number of genes in the genome.
false
Translation begins when the DNA in a chromosome unwinds and one strand is used as a template to make a pre-mRNA molecule.
false
Viral infections are not considered a risk factor for autosomal trisomy because a virus cannot affect human chromosome arrangement.
false
mRNA is made up of introns that have been spliced together.
false
The major physical symptom associated with Klinefelter syndrome is ____.
fertility problems
The most important events in human development occur during the ____.
first trimester
If two genes control a trait and each has a dominant and a recessive allele, there are ____ phenotypic classes in the F2 generation.
five
There are ____ basic patterns of Mendelian inheritance.
five
In obesity studies in mice, the binding of leptin activates the leptin receptor and initiates changes in ____ in the hypothalamus.
gene expression
What Mendel called "factors," we now call ____.
genes
A trait with a heritability value of 0.75 indicates that 75% of the phenotypic variability seen in the population is caused by ____ of the population.
genetic differences
Single nucleotide polymorphisms (SNPs) are organized into blocks called ____ and are inherited together.
haplotypes
A cell in G0 state ____.
has entered a resting stage and is not actively dividing
Genetics is defined as the scientific study of ____.
heredity
The offspring (F1) resulting from the cross between two red flowered plants are 3/4 red and 1/4 white. The most likely genotype of both red flowered parental plants (P1) is ____.
heterozygous
A blastocyst ____.
implants in the endometrium
A Barr body is a(n) ____.
inactivated x chromosome
Deletion of an entire autosome ____.
is lethal
Large cellular polymers assembled by chemically linking monomers together are called ____.
macromolecules
The methods of ____ have had the greatest impact on human genetics in recent decades.
molecular genetics
Spina bifida is one of the most common and most complex birth defects involving the ____ system.
nervous
More than ____ percent of couples decide to terminate a Down syndrome pregnancy.
ninety
Purines and pyrimidines are two classes of organic bases found in ____.
nucleic acids
The basic building block of DNA and RNA is a(n) ____.
nucleotide
In meiosis of oogenesis, how many mature eggs result?
one
Ockham's razor could also be called the principle of ____.
parsimony
Which biomolecule is most associated with the structure and function of cell membranes?
phospholipids
The search for a(n) ____ treatment led to the discovery that DNA carries genetic information.
pneumonia
Mendel analyzed his pea plant data using the principles of ____.
probability
Seminal vesicles secrete fructose and ____ into the semen
prostaglandins
Variant Creutzfeldt-Jakob disease is caused by errors in ____.
protein folding
Ribosomes are organelles that are involved in ____.
protein synthesis
In an XX embryo, ____ inactivation of one X chromosome usually occurs when the embryo has about 32 cells.
random
In a(n) ____ translocation, two nonhomologous chromosomes exchange parts and no genetic information is gained or lost from the cell in the exchange.
reciprocal
The development and use of ____ ushered in the era of genomics when geneticists began planning ways to sequence the 3.2 billion nucleotides in the human genome.
recombinant DNA technology
The concept of ____ explains why children of parents who are at the extreme ends of a normal (bell-curve) distribution for a phenotype are usually closer to the population average for the phenotype.
regression to the mean
The sugar in RNA nucleotides is ____.
ribose
In humans, body size, muscle mass, and patterns of fat distribution are types of ____ sex characteristics.
secondary
Pattern baldness is a(n) ____ trait.
sex-influenced
When constructing a karyotype, the chromosome images are arranged in pairs according to ____________________ and ____________________.
size; centromere location
During spermatogenesis in meiosis II, ____ form(s).
spermatids
Regions at the ends of chromosomes that prevent chromosomes from sticking to each other are called ____.
telomeres
About ____ percent of children with Down syndrome are severely intellectually disabled.
ten
Most evidence indicates that skin color is controlled by ____ gene pair(s).
ten
Any physical or chemical agent that brings about an increase in congenital malformations is called a(n) ____.
teratogen
Studies of sex chromosome aneuploidy reveal that ____ necessary for survival.
the Y chromosome is not
____ nucleotides form the code for one amino acid.
three
One type of polyploidy is ____.
triploidy
The most common type of polyploidy in humans is ____.
triploidy
A polar body, once formed, has no further function and dies.
true
Autosomal chromosome pairs are identical, whereas the sex chromosome pair in males is not.
true
Crossing over is partially responsible for our genetic diversity.
true
One treatment for Gaucher disease is enzyme replacement therapy.
true
Using fetal DNA from the mother's blood for prenatal testing is a noninvasive procedure.
true
A measured heritability of 0.7 means that 70% of the phenotypic variation observed is due to genetic differences within the population.
true
A replicated DNA molecule contains one new strand and one old strand.
true
Abraham Lincoln's son, Robert, showed no signs of Marfan syndrome.
true
Adenine and guanine are nitrogen-containing bases found in nucleic acids.
true
An embryo that is composed of a hollow ball of cells is called a blastocyst.
true
An mRNA molecule has a cap attached to its 5' end and a poly-A tail attached to its 3' end.
true
Complete androgen insensitivity causes XY males to become phenotypic females.
true
Continuous phenotypic variations can be explained by Mendelian inheritance.
true
Dizygotic twins originate from two separate fertilization events.
true
Down syndrome can be caused by either trisomy 21 or a Robertsonian translocation.
true
Duchenne muscular dystrophy and Becker's muscular dystrophy are caused by different mutations in the same X-linked gene.
true
During translation, the rRNA in the large ribosomal subunit acts as an enzyme, linking amino acids together to form a polypeptide.
true
For threshold traits, the liability for a genetic disorder is distributed among individuals in a bell-shaped curve.
true
Gonadal sex and sexual phenotype in males and females are produced by separate developmental pathways by the action of different gene sets.
true
Heritability studies cannot provide information about the number, location, or identity of genes involved in specific complex traits.
true
If a dihybrid cross is begun with a P1 generation of a true-breeding plant that produces smooth and yellow peas (smooth and yellow are both dominant traits), crossed with a plant that produces wrinkled green peas (wrinkled and green are both recessive traits), the F1 plants will all be smooth and yellow.
true
If a pedigree analysis suggests that an autosomal or X-linked inheritance pattern is equally likely, then additional genetic testing is needed to identify the pattern of inheritance.
true
Incomplete dominance is the expression of a phenotype that is intermediate to those of the parents.
true
Leukemia is often associated with chromosomal translocations.
true
Males never give an X chromosome to any of their sons.
true
Methylmalonic acidemia (MMA) is caused by the inability to metabolize amino acids and fats.
true
Pedigree construction can be a difficult task.
true
Phenotypic variation can occur in traits controlled by the same allele.
true
Prion diseases are always fatal and there is no treatment.
true
Recessive traits are expressed only in the homozygous state.
true
Rosalind Franklin did not share a part of the 1962 Nobel Prize for Medicine or Physiology because she had died four years earlier.
true
Sperm mature and are stored in the epididymis.
true
The H5N1 influenza killed more than 50% of those infected.
true
The codon encoding the amino acid methionine functions as a start codon when it occurs at the beginning of a gene.
true
The frequency of heterozygotes for cystic fibrosis shows ethnic variations.
true
The genes discovered to date account for only about 5-10% of the total variation in adult height.
true
The inheritance of sex-influenced traits can be dominant in one sex but recessive in the other.
true
The interphase nucleus has an internal structure in which each chromosome occupies a distinct region called a chromosome territory.
true
The most common mutation in cystic fibrosis is the deletion of a single amino acid which results in a misfolded protein.
true
The process of transferring genetic information between bacterial cells is accomplished with a transformation factor called DNA.
true
The risk of having a child with Down syndrome due to a chromosomal translocation is independent of maternal age.
true
Trisomy 21 is the only autosomal trisomy that allows survival into adulthood.
true
Turner syndrome is not associated with intellectual disability.
true
Twenty different types of amino acids are used to make proteins.
true
When analyzing a cross involving two traits, each trait is analyzed separately, and then the frequencies of each are combined to yield the observed phenotypic ratios.
true
In RNA, the base ____ takes the place of the base thymine.
uracil
The immune system ____.
works by attacking anything recognized as foreign
If a pedigree of several generations shows only females affected by a particular trait, it cannot be a(n) ____ trait.
y-linked
What is an example of basic research?
Learning how plants turn carbon dioxide into sugar
The process of post-transcriptional gene silencing triggered by micro-RNA molecules that stop translation is called ____.
RNA interference
Polyploidy is characterized by ____.
a chromosomal number that is a multiple of the normal haploid chromosomal set
The initial circumstance that led some to believe that Abraham Lincoln had Marfan syndrome was that ____ had the disease.
a descendent of Lincoln's great-great-grandfather
Carbohydrates ___.
act as energy sources for cells
In a pedigree, a person whose symbol is filled in and who is associated with the Roman numeral II is ____.
affected by the trait and in the second generation
Autosomes represent ___.
all chromosomes other than the sex chromosomes
Mitochondria are transmitted from mothers to ____.
all of their children through the cytoplasm of the egg
During the elongation step of translation, ____.
amino acids are added to a growing polypeptide chain
Peptide bonds form between ____.
an amino group and a carboxyl group
Amino acids are characterized by ____.
an amino group, a carboxyl group, and an R group
Phenotype is ____.
an observable property or expression of a trait in an organism
In the Watson-Crick model of DNA structure, the polynucleotide chains ____.
are oriented in opposite directions
Sex-influenced traits are expressed ____.
as a result of hormone differences between males and females
Proteins function ___.
as component parts of enzymes
In meiosis, cells become haploid ____.
at the end of telophase I
In the early 1950s, James Watson and Francis Crick ____.
began to work out the structure of DNA by organizing the information about DNA that was already available
At one end of a tRNA molecule is a sequence of 3 nucleotides called an anticodon that ____.
binds to its complementary mRNA codon
Genetic testing for complex traits ____.
cannot exactly define risks
Y-linked traits are ____.
carried only by males and transmitted only to males
A phosphate group is a compound containing phosphorus ____.
chemically bonded to four oxygen molecules
One important difference between amniocentesis and chorionic villus sampling is that ____.
chorionic villus sampling can be done earlier in the pregnancy than amniocentesis
Gregor Mendel ____ .
claimed that each individual carries a pair of "factors" for a given trait
Nucleosomes are bead-like structures ____.
composed of histone wrapped with DNA
The hormone oxytocin stimulates ____.
contraction of uterine muscles during childbirth
A centromere is least likely to ____.
cross over during prophase I of meiosis
Hemophilia is characterized by ____.
defects in the mechanism of blood clotting
The main purpose of preparing karyotypes is to ____.
diagnose or rule out certain genetic disorders
The tall and short phenotypes in pea plants are examples of ____.
discontinuous traits
One characteristic of an autosomal dominant trait is that ____.
every affected individual has at least one affected parent
Mendel's pea plants made good experimental subjects because they ____.
exhibit discontinuous variation and complete dominance
Cleft palate is ____.
explained by the threshold model of complex traits
The tertiary structure of a protein is ____.
formed by a protein region folding on itself
SARS symptoms include ____.
high fever, headaches, and respiratory problems
If a man expresses an X-linked recessive trait, ____.
his mother was heterozygous or homozygous for the trait
In genetics, a chi-square test can be used to determine ____.
how closely actual results of a cross match the expected results
Proteins contain twenty different subunits ____.
in the form of amino acids
A trait shows ____ if the phenotype of that trait is present in less than 100% of those with the related genotype.
incomplete penetrance
Bacteriophages are viruses that ____.
infect and copy themselves inside bacterial cells
Tetracyclines interfere with ____.
initiation of translation
Gene therapy can best be described as the ____.
insertion of normal genes to act in place of mutant genes
In pre-mRNA processing, ____.
introns are spliced out and the exons are combined in the mature mRNA
Eugenics ___.
is a dubious method for improving the human species through selective breeding
During interaction between genes and environment, the phenotype ____.
is variable and undergoes continuous change throughout the life of the organism
Friedrich Miescher, after he began to study the chemical composition of the nucleus, was one of the first to ____.
isolate and purify a cellular organelle
The decline of the eugenics movement in the U.S. in the early 20th century resulted from ____.
its misuse for social and political purposes by the Nazis
Telomeres are short DNA sequences ____.
located at each end of a chromosome
Histones are the ____.
major class of proteins in chromatin
In his monohybrid crosses, Mendel deduced that one trait was recessive because that trait was ____.
not present in the F1 and reappeared in the F2
The chorionic villi eventually form the placenta, a disc-shaped structure that ____.
nourishes the embryo throughout pregnancy
Genomic technology allows researchers to use ____ to survey the genome to detect associations between common variations and a specific phenotype.
nucleotide variations
A cell that cannot form spindle fibers cannot ____.
perform mitosis nor meiosis
One characteristic of continuous variation is that ____.
phenotypic expression varies across a wide range
The X and Y chromosomes ____.
play major roles in determining the sex of an individual
The secondary structure of a protein forms ____.
pleated sheets or coils
Induced pluripotent stem cells are ____
produced from normal body cells
Which genetic diseases involve defects in DNA repair that affect cell division?
progeria and Werner syndrome
The heritability of a trait is the ____.
proportion of phenotypic variation that is caused by different genotypes
Pedigrees ____.
provide information on the patterns of inheritance of a trait
Once the strands of DNA are separated, the enzyme DNA polymerase ____ and links nucleotides together.
reads the nucleotide sequence of the template strand
Prions are created when normal proteins in the body ____.
refold into a different and infectious three-dimensional shape that kills cells in the brain and nervous system
A human pedigree ___.
represents the inheritance of a trait through several generations of a family
Independent assortment means that the ____.
segregation of one gene pair occurs as if no other gene pair was present
DNA vaccines ____.
show promise in animal studies and are now in clinical trials
Messenger RNA is a(n) ____ of the amino acid-coding nucleotide sequence of a gene.
single-stranded complementary copy
The letters G, Q, R, and C, used to describe the appearance of chromosomes, refer to the ____.
staining procedure used to reveal the bands
Transmission genetics ___.
studies the pattern of inheritance as traits are passed from generation to generation
Most protein synthesis ____.
takes place on the surface of the rough endoplasmic reticulum
The undifferentiated genitalia of an early human embryo develops into male genitalia under the influence of ____.
testosterone, AMH, and DHT
The underlying problem in Gaucher disease is ____.
the accumulation of fat in white blood cells
Ribosomes are most closely associated with ____.
the cytoplasm and rough endoplasmic reticulum
Darker skin color is correlated with ____.
the intensity of UV radiation
A locus is ___.
the location of a gene on a chromosome
The Hayflick limit describes ____.
the number of divisions a cultured cell can undergo
In a P1 cross involving incomplete dominance, ____.
the phenotypic ratio and genotypic ratio in the F1 are identical
In codominant inheritance, ____.
there is full phenotypic expression of both members of a gene pair in the heterozygous condition
Mendel selected pea plants for his experiments because ____.
they can be self-fertilized or artificially fertilized by hand
Some forms of methylmalonic acidemia can be ____.
treated successfully if the condition is detected early in life
In addition to fertilizing the egg, sperm also ____.
trigger chemical changes in the egg that prevent the entry of more than one sperm
Codons are ____ that encode the information for a specific amino acid in a protein.
triplets of nucleotides in mRNA
In autosomal dominant inheritance, ____.
two affected individuals may have unaffected children
In a monohybrid cross with complete dominance, the F2 offspring should contain ____.
two different phenotypes and three different genotypes
Carrie Buck is significant in the history of genetics because she ____.
was sterilized after the U.S. Supreme Court determined she was feebleminded
The risk for Down syndrome increases ____.
when the mother is over thirty-five years old
One goal of pedigree analysis is to determine ____.
whether a gene has a dominant or recessive pattern of inheritance