exam 3 key

Question 1

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)?

Answer 1

nucleotide, DNA duplex, nucleosome, chromatid, chromosome

Question 2

ch 13

during the shotgun approach to genome sequencing, the sequenced fragments originate from:

Answer 2

targeted sites scattered across the genome

Question 3

ch 13

how can researches distinguish exons from introns?

Answer 3

the sequence of exons complements the mRNA sequence

Question 4

ch 13

complex organisms can be characterized as having:

Answer 4

none of the answer options is correct: there is no correlation between the complexity between an organism and these characteristics

Question 5

ch 13

the genome of viruses consists of:

Answer 5

viruses genomes can contain any of the nucleic acids listed

Question 6

ch 13

which of the following steps comes first in sequencing?

Answer 6

breaking the DNA info

Question 7

ch 13

once the nucleosomes have formed the nucleosomes and associated DNA are coiled to form a structure called the

Answer 7

30-nm chromatin fiber

Question 8

ch 13
the comparison between the number of human genes and those of other animal species has led to many conclusions, including that __

Answer 8

the number of protiens expressed by the human genome is far more than the number of its genes

Question 9

ch 14

the relatively large number of new mutations that occur in the human genome each generation is tolerable because;

Answer 9

most of our genome is non-coding DNA, so few mutations affect our protiens

Question 10

ch 14

what is the advantage of the proofreading function of DNA polymerase?

Answer 10

DNA polymerase can repair most mutations as they occur during DNA replication

Question 11

ch 14

in organisms with large genomes, inversions typically occur in

Answer 11

noncoding DNA

Question 12

ch 14

insertions and deletions that occur in multiples of three nucleotides:

Answer 12

add or delete amino acids to/from the normal polypeptide

Question 13

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:

Answer 13

some individuals in the original population had the mutations that lead to resistance

Question 14

ch 14

mismatch repair, base excision repair, and nucleotide excision repair are similar in that

Answer 14

each uses an undamaged segment of DNA as a template to repair a damaged segment of DNA

Question 15

ch 14

__ mutations are important to the evolutionary process; most cancers result from __ mutations.

Answer 15

germ-line; somatic

Question 16

ch 14

which of the following is a large-scale mutation?

Answer 16

insertion

Question 17

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:

Answer 17

may be harmful in one environment and beneficial in another

Question 18

ch 15

the phenotype of an individual results from an interaction between:

Answer 18

genotype and the environment

Question 19

ch 15

most genetic variation in populations is:

Answer 19

neutral

Question 20

ch 15

which of the following statements about restriction fragment length polymorphisms (RFLPs) is correct?

Answer 20

all of the answer options is correct

Question 21

ch 15
when DNA with variable number tandem repeats (VNTRs) is sequenced and visualized on a gel, the resulting fragments separate according to their:

Answer 21

size

Question 22

ch 15

harmful mutations are often eliminated in a population because:

Answer 22

the decrease survival and reproduction of the indivuduals

Question 23

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?

Answer 23

XXY and XO

Question 24

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?

Answer 24

no, she should not worry about her children because this did not occur in a germ-line cell

Question 25

ch 16

Mendel’s principle of independent assortment corresponds to which part of meiosis?

Answer 25

random alignment of the homologous on the metaphase plate during metaphase I

Question 26

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?

Answer 26

phenotype

Question 27

ch 16

two plants are crossed, resulting in offspring with a 3:1 ratio for a particular trait. this ratio suggests that __

Answer 27

the parents were both heterozygous for the particular trait

Question 28

ch 16

segregation of the alleles corresponds to the separation of:

Answer 28

chromosomes

Question 29

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?

Answer 29

A, B, and C are all correct

Question 30

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

Answer 30

recessive

Question 31

ch 16

according to the principle of segregation, a heterozygous plant with alleles Aa will produce:

Answer 31

50% of gametes with the A and 50% of gametes with the a allele, on average

Question 32

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?

Answer 32

RRFF and RrFr only

Question 33

ch 17

the fact that the ratio of human male to female births is nearly 1:1 demonstrates that

Answer 33

X and Y chromosomes demonstrate segregation and random fertilization

Question 34

ch 17

in animals with sex chromosomes, males inherit their X chromosomes from their __ and transmit them to their __.

Answer 34

mothers/daughters

Question 35

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)?

Answer 35

half of the daughters would be color blind

Question 36

ch 17

the frequency of recombination during meiosis is a function of:

Answer 36

the distance between genes; the farther apart the genes are, the more frequent the recombination between them

Question 37

ch 17

Y- linked traits are:

Answer 37

never inherited or transmitted by females, they are transmitted by affected fathers only to their sons

Question 38

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?

Answer 38

the Y is paired with a functional X chromosome, which has all the genes

Question 39

ch 17
Mendel’s ground breaking experiments with 7 pairs of contrasting traits in pea plants did not resolve the concept of linkage because

Answer 39

each of the 7 pairs of traits happened to be controlled by seven different genes, each on a distinct autosome

Question 40

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?

Answer 40

the phenotype of a son will determine at least one of the alleles in the mother’s genotype

Question 41

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?

Answer 41

their daughters are expected to be heterozygous for the associated gene

Question 42

ch 18
a key difference between single-gene traits such as those Mendel studied and complex traits such as human height is that:

Answer 42

single-gene traits are generally uninfluenced by the environment, whereas complex traits have a significant environmental componenet

Question 43

ch 18

inbred lines of animals, such as lab mice, are useful for studying complex traits because:

Answer 43

individuals are genetically identical, so differences in traits must be due to environmental differences

Question 44

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 __.

Answer 44

0; 0

Question 45

ch 18

a trait with high heritability will:

Answer 45

respond quickly to both artificial selection and narural selection

Question 46

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:

Answer 46

the interaction of their diet with their genotype

Question 47

ch 18

heritability is defined as:

Answer 47

the proportion of the total variation due to genetic differences among individuals

Question 48

ch 18

concordance is

Answer 48

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

Question 49

ch 18

when heritability is 100%, the variation among individuals in the population is due to;

Answer 49

genotype

Question 50

bonus

why is “chain reaction” an appropriate part of the term “PCR”?

Answer 50

newly synthesized DNA segments serve as templates in subsequent cycles

Question 51

bonus

how many human chromosomes could fit into a single bacterial cell?

Answer 51

none

Question 52

bonus

cancer is usually due to:

Answer 52

a series of mutations that occur in a single lineage of somatic cells

Question 53

bonus

studying 2 traits in fruit flies……

Answer 53

red segregated from brown in meiosis I, and straight segregated from curled in meiosis I

Question 54

bonus

in humans, mitochondria (and their genomes) show:

Answer 54

strict maternal inheritance