exam 3 key Flashcards
ch 13
in eukaryotes, genetic material is packaged in the nucleus. which of the following most accurately lists the components in order from increasing size (smallest to largest)?
nucleotide, DNA duplex, nucleosome, chromatid, chromosome
ch 13
during the shotgun approach to genome sequencing, the sequenced fragments originate from:
targeted sites scattered across the genome
ch 13
how can researches distinguish exons from introns?
the sequence of exons complements the mRNA sequence
ch 13
complex organisms can be characterized as having:
none of the answer options is correct: there is no correlation between the complexity between an organism and these characteristics
ch 13
the genome of viruses consists of:
viruses genomes can contain any of the nucleic acids listed
ch 13
which of the following steps comes first in sequencing?
breaking the DNA info
ch 13
once the nucleosomes have formed the nucleosomes and associated DNA are coiled to form a structure called the
30-nm chromatin fiber
ch 13
the comparison between the number of human genes and those of other animal species has led to many conclusions, including that __
the number of protiens expressed by the human genome is far more than the number of its genes
ch 14
the relatively large number of new mutations that occur in the human genome each generation is tolerable because;
most of our genome is non-coding DNA, so few mutations affect our protiens
ch 14
what is the advantage of the proofreading function of DNA polymerase?
DNA polymerase can repair most mutations as they occur during DNA replication
ch 14
in organisms with large genomes, inversions typically occur in
noncoding DNA
ch 14
insertions and deletions that occur in multiples of three nucleotides:
add or delete amino acids to/from the normal polypeptide
ch 14
a population of mosquitoes is exposed to the pesticide DDT for several generations. at the end of that time, most individuals in the population are resistant to DDT. The most likely reason is that:
some individuals in the original population had the mutations that lead to resistance
ch 14
mismatch repair, base excision repair, and nucleotide excision repair are similar in that
each uses an undamaged segment of DNA as a template to repair a damaged segment of DNA
ch 14
__ mutations are important to the evolutionary process; most cancers result from __ mutations.
germ-line; somatic
ch 14
which of the following is a large-scale mutation?
insertion
ch 15
ultraviolet light is a mutagen, but humans need some exposure to it to synthesize vitamin D. The amount of ultraviolet light that penetrates the skin depends on the skins pigmentation: more melanin means less penetration. certain mutations result in decreased melanin production. such mutations:
may be harmful in one environment and beneficial in another
ch 15
the phenotype of an individual results from an interaction between:
genotype and the environment
ch 15
most genetic variation in populations is:
neutral
ch 15
which of the following statements about restriction fragment length polymorphisms (RFLPs) is correct?
all of the answer options is correct
ch 15
when DNA with variable number tandem repeats (VNTRs) is sequenced and visualized on a gel, the resulting fragments separate according to their:
size
ch 15
harmful mutations are often eliminated in a population because:
the decrease survival and reproduction of the indivuduals
ch 15
nondisjunction of X chromosomes may occur during meiosis 1 of oogenesis to form 2 types of eggs. if normal sperm fertilize these two types of egg, which of the following are possible sex chromosome complements?
XXY and XO
ch 15
cancer can be caused by mutations. genetic analysis of Anna Karenena’s tumor shows that the cell proliferation was triggered by a somatic mutation in the MYC gene, causing this gene to be inappropriately activated. Anna is concerned about passing this cancer on to the children she plans to have in the future. should this be a concern?
no, she should not worry about her children because this did not occur in a germ-line cell
ch 16
Mendel’s principle of independent assortment corresponds to which part of meiosis?
random alignment of the homologous on the metaphase plate during metaphase I
ch 16
Mendel studies seven different traits in the garden pea. What genetic term is used to describe an observable trait, such as these studied by Mendel?
phenotype
ch 16
two plants are crossed, resulting in offspring with a 3:1 ratio for a particular trait. this ratio suggests that __
the parents were both heterozygous for the particular trait
ch 16
segregation of the alleles corresponds to the separation of:
chromosomes
ch 16
which of the following would have caused Mendel to observe patterns of inheritance that supported the model of blending inheritance rather than the transmission of alleles causing discrete differences?
A, B, and C are all correct
ch 16
you are examining a human pedigree for a trait. you notice that an offspring can be affected even if neither parent is affected. this immediately tells you that the trait is
recessive
ch 16
according to the principle of segregation, a heterozygous plant with alleles Aa will produce:
50% of gametes with the A and 50% of gametes with the a allele, on average
ch 16
in humans, ability to roll the tongue (R) is dominant in being unable to is dominant to being unable to roll (r). Having freckles in dominant (F) to being able to have no freckles (f). A freckled tongue-roller could have which of the following genotypes?
RRFF and RrFr only
ch 17
the fact that the ratio of human male to female births is nearly 1:1 demonstrates that
X and Y chromosomes demonstrate segregation and random fertilization
ch 17
in animals with sex chromosomes, males inherit their X chromosomes from their __ and transmit them to their __.
mothers/daughters
ch 17
red/green color blindness is a sex linked recessive trait in humans. if a carrier female (heterozygous for the trait) mated with an affected man, what would be the expected outcome(s)?
half of the daughters would be color blind
ch 17
the frequency of recombination during meiosis is a function of:
the distance between genes; the farther apart the genes are, the more frequent the recombination between them
ch 17
Y- linked traits are:
never inherited or transmitted by females, they are transmitted by affected fathers only to their sons
ch 17
the human X chromosome carries approximately 1000 genes. the Y chromosome contains only about 50 genes. how can males survive with only these 50 genes on the Y chromosome?
the Y is paired with a functional X chromosome, which has all the genes
ch 17
Mendel’s ground breaking experiments with 7 pairs of contrasting traits in pea plants did not resolve the concept of linkage because
each of the 7 pairs of traits happened to be controlled by seven different genes, each on a distinct autosome
ch 17
in some cases, for X-linked traits, the genotype of a parent can be determined by the phenotype of their children. In which of the following scenarios is this true?
the phenotype of a son will determine at least one of the alleles in the mother’s genotype
ch 17
considering an X linked dominant trait, if an unaffected woman and an affected man decided to have children, then which of the following statements is true about the possibilities for their children?
their daughters are expected to be heterozygous for the associated gene
ch 18
a key difference between single-gene traits such as those Mendel studied and complex traits such as human height is that:
single-gene traits are generally uninfluenced by the environment, whereas complex traits have a significant environmental componenet
ch 18
inbred lines of animals, such as lab mice, are useful for studying complex traits because:
individuals are genetically identical, so differences in traits must be due to environmental differences
ch 18
if all variation among individuals in a population is due to differing environments, heritability is __, and the slope of the line used to measure it is __.
0; 0
ch 18
a trait with high heritability will:
respond quickly to both artificial selection and narural selection
ch 18
ten individuals of two inbred strains of mice, A and B, are fed identical diets. All have normal blood sugar as adults. The same mice are then fed diets high in sugar. Mice from strain B develop diabetes, but mice from strain A don’t. Diabetes in strain B results from:
the interaction of their diet with their genotype
ch 18
heritability is defined as:
the proportion of the total variation due to genetic differences among individuals
ch 18
concordance is
the percentage of cases in which both members of a pair of twins show the trait when it is known that at least one member shows it
ch 18
when heritability is 100%, the variation among individuals in the population is due to;
genotype
bonus
why is “chain reaction” an appropriate part of the term “PCR”?
newly synthesized DNA segments serve as templates in subsequent cycles
bonus
how many human chromosomes could fit into a single bacterial cell?
none
bonus
cancer is usually due to:
a series of mutations that occur in a single lineage of somatic cells
bonus
studying 2 traits in fruit flies……
red segregated from brown in meiosis I, and straight segregated from curled in meiosis I
bonus
in humans, mitochondria (and their genomes) show:
strict maternal inheritance
