Week 3- Quizzes, Animations, Clicker Questions

Question 1

What is an SNP?

A., a single nucleotide polymorphism

B., a location where individual alleles differ by one base pair

C., a genetic difference that can occur between different individuals

D., All of these choices are correct.

Answer 1

D., All of these choices are correct.

Question 2

Which of the following is not part of a microarray used to detect SNPs?

A., short DNA sequences attached to a glass slide

B., oligonucleotides that match the sequence of a known SNP site in the genome

C., mRNAs that are expressed from a specific gene

D., short DNA sequences synthesized with a specific sequence

E., oligonucleotides that differ in sequence only at the SNP itself and are positioned at different locations on a glass slide

Answer 2

C., mRNAs that are expressed from a specific gene

Question 3

Which of the following is not part of the process of using a microarray to detect SNPs in an individual’s DNA?

A., DNA from the individual is isolated from his or her cells.

B., Sequences from the region containing the SNP are amplified.

C., Amplified DNA is labeled with a fluorescent dye.

D., Proteins from the gene are allowed to stick to the microarray.

E., DNA is hybridized to the oligonucleotides to allow exact base pairing.

Answer 3

D., Proteins from the gene are allowed to stick to the microarray.

Question 4

How are SNP alleles in an individual detected using a microarray?

A., The DNA from the individual is sequenced using dideoxy sequencing.

B., The location on the microarray of the hybridizing DNA is visualized using a microscope.

C., DNA primers on each side of the SNP are hybridized for PCR.

Answer 4

B., The location on the microarray of the hybridizing DNA is visualized using a microscope.

Question 5

How will SNP microarray results differ in an analysis of DNA from an individual who is homozygous for one allele compared with an individual who is heterozygous for both alleles?

A., The strength of the fluorescent glow will be stronger in the analysis of DNA from the homozygous individual.

B., The fluorescent signal will be detected for both A−T and G−C base pairs in analysis of DNA from the heterozygous individual, but for only one of these base pairs in DNA from homozygotes.

C., DNA from heterozygous individuals will not be hybridized to the microarray, but base-pair matching hybridization will occur using DNA from heterozygotes.

Answer 5

B., The fluorescent signal will be detected for both A−T and G−C base pairs in analysis of DNA from the heterozygous individual, but for only one of these base pairs in DNA from homozygotes.

Question 6

How many SNPs can be detected using a single microarray?

A., 1

B., 2

C., 46

D., millions

Answer 6

D., millions

Question 7

For an SNP with three alleles, how many different diploid genotypes are possible?

5

4

7

6

3

Answer 7

6

Question 8

A new gene is discovered that dramatically aids in the digestion of fish. You hypothesize that populations with a history of being near the shoreline would have more copies of this gene than populations found farther inland. How would you classify this genetic difference?

SNP

CNV

RFLP

VNTR

None of the answer options is correct

Answer 8

CNV

Question 9

A newly arisen point mutation always creates an SNP.

False

True

Answer 9

False

Question 10

Much of the genetic variation seen in the human population is neutral.

False

True

Answer 10

True

Question 11

Saying that a SNP is associated with a disease means that if you possess that particular SNP, you will end up with that disease.

True

False

Answer 11

False

Question 12

SNPs arise from:

inversions.

duplications.

deletions.

translocations.

point mutations.

Answer 12

point mutations.

Question 13

First division nondisjunction will only yield gametes with an extra chromosome, whereas second division nondisjunction will only yield gametes missing a chromosome.

False

True

Answer 13

False

Question 14

The failure of a pair of chromosomes to separate during anaphase is referred to as:

trisomy.

translocation.

inversion.

disjunction.

nondisjunction.

Answer 14

nondisjunction.

Question 15

What is one reason a woman with the genotype XXX are not phenotypically different from an XX female?

The extra X chromosome only becomes active in nonreproductive areas of the body.

Only one X is active in each cell, regardless of how many X chromosomes there are in a cell.

We have enzymes that will recognize and degrade the extra X chromosome.

The X chromosome only carries genes dealing with being a female, so having another one doesn’t matter.

None of the answer options is correct.

Answer 15

Only one X is active in each cell, regardless of how many X chromosomes there are in a cell.

Question 16

Consider a normal human cell in which one chromosome undergoes nondisjunction in mitosis. What chromosome numbers would be found in the daughter cells?

45 and 47

45 and 46

None of the answer options is correct.

46 and 46

46 and 47

Answer 16

45 and 47

Question 17

Which of the following is true?

A., Down syndrome is the one inherited disorder that results from an extra copy of an entire chromosome.

B., Down syndrome is caused by errors in fertilization.

C., Errors in chromosome segregation can occur in either the first or second meiotic division.

D., Nondisjunction can only produce gametes with extra chromosomes, not missing chromosomes.

Answer 17

C., Errors in chromosome segregation can occur in either the first or second meiotic division.

Question 18

In normal meiosis, when do homologous chromosomes separate from each other?

A., in the first meiotic division

B., in the second meiotic division

C., They may separate in either the first or second meiotic divisions.

Answer 18

A., in the first meiotic division

Question 19

What is nondisjunction?

A., failure of chromosomal replication

B., failure of chromosomal separation

C., failure of chromosomal condensation

D., failure of chromosomal pairing

Answer 19

B., failure of chromosomal separation

Question 20

If nondisjunction occurs in the first meiotic division, how many of the four possible gametes produced from meiosis will have the wrong number of chromosomes?

A., one

B., two

C., three

D., four

Answer 20

D., four

Question 21

In which type of nondisjunction could the two copies of a chromosome in a gamete be heterozygous?

A., nondisjunction in the first meiotic division

B., nondisjunction in the second meiotic division

C., Nondisjunction in either meiotic division could produce gametes with two copies of a chromosome that are heterozygous.

Answer 21

A., nondisjunction in the first meiotic division

Question 22

Similar to single gene traits, traits determined by multiple genes also show the expected 3:1 ratio of phenotypes in the progeny between two heterozygotes.

True

False

Answer 22

False

Question 23

Genotype-by-environment interaction means that genetic and environmental influences may interact or contribute to the phenotypic outcomes in unpredictable ways.

True

False

Answer 23

True

Question 24

Most complex traits are: (Select all that apply.)

affected by multiple genes.

homozygous for all alleles affecting the trait.

affected by environmental factors.

heterozygous for all alleles affecting the trait.

inherited in pedigrees showing simple Mendelian patterns.

affected by interactions between genes and environmental factors.

Answer 24

affected by multiple genes.

affected by environmental factors.

affected by interactions between genes and environmental factors.

Question 25

A complex trait can be influenced by the environment.

True

False

Answer 25

True

Question 26

Sunlight exposure has stronger effect on skin cancer risk in fair-skinned humans than in individuals with darker skin. This is an example of:

genotype-by-environment interaction.

epistasis.

differences in the norm of reaction.

pleiotropy.

All of these choices are correct.

Answer 26

genotype-by-environment interaction.

Question 27

Which of the following statements BEST reflects the extent to which we can distinguish the effects of genes and the environment on the expression of a complex trait?

For identical twins raised in the same environment, height should not differ by more than 20%.

About 80% of an individual’s height is determined by genes and 20% by environment.

If one individual is 60 inches tall and another is 70 inches tall, they differ in about 80% of their genes.

In a group of individuals of the same sex, about 80% of the variation in height among individuals is due to genetic differences and 20% is due to environmental differences.

None of answer options is correct.

Answer 27

In a group of individuals of the same sex, about 80% of the variation in height among individuals is due to genetic differences and 20% is due to environmental differences.

Question 28

Which of the following is not an example of a complex trait?

A., height in humans

B., milk production in dairy cows

C., smooth or wrinkled pea seeds

D., grain yield in corn

Answer 28

C., smooth or wrinkled pea seeds

Question 29

The actual offspring mean height in the graph lies between the parental mean line and the population mean because:

A., during meiotic cell division segregation and recombination break up combinations of genes leading to extreme phenotypes (e.g., very tall or very short).

B., the phenotypes of the parents result from both their genes and their environment.

C., the phenotypes of the offspring result from both their genes and their environment.

D., all of the above will affect the relationship between parent mean height and offspring mean height.=

E., only choices a and c will affect the relationship between parent mean height and offspring mean height.

Answer 29

D., all of the above will affect the relationship between parent mean height and offspring mean height.=

Question 30

The graph indicates that on average the offspring of short parents will be taller than their parents, and the offspring of tall parents will be shorter than their parents.

A., true

B., false

Answer 30

A., true

Question 31

If all variation in height among humans was due to environmental influences alone, the mean height of offspring when graphed against the mean height of parents should be closest to which line in the graph above?

A., the parental mean line

B., the population mean line

Answer 31

B., the population mean line

Question 32

If all variation among individuals in a population is due to differing genotypes alone, heritability is _____, and the slope of the line used to measure it is _____.

50%; 1

100%; 1

100%; 0.5

50%; 0.5

0%; 0

Answer 32

100%; 1

Question 33

A trait with high heritability responds rapidly to selection, whereas a trait with a low heritability responds slowly or not at all.

False

True

Answer 33

True

Question 34

An example of “regression toward the mean” would be if the offspring of two short parents had an average height equal to the average height of the parents?not of the population as a whole.

True

False

Answer 34

False

Question 35

When heritability is 0%, genes play:

a role in the expression of a trait, but it can’t be measured.

no role in the expression of the trait.

a role in variation in the trait among individuals, but it cannot be measured.

a role in the expression of a trait, but only a small one.

no role in variation in the trait among individuals.

Answer 35

no role in variation in the trait among individuals.