ch 16 biology

True or false: Variable expressivity implies that the disease may not always be present (in individuals with a genotype that "should" lead to disease).

false

Genes that modify the expression of other genes show:

epistasis

Your grandmother has a rare disease for which a new genetic test has just been developed. If you are interested in a genetic test to determine whether you are affected, which of the following would you need to know to best interpret your test?

The penetrance of disease in people of your genotype

You have an F2 generation derived from two true-breeding parents with different characteristics for the same trait (determined by a single allele). What percentage of the F2 generation with a dominant phenotype would you expect to be true breeding if they were self-fertilized?

33%

True or false. A Punnett square can be used to interpret the results of a testcross.

true

You are given two true-breeding groups of rabbits. The first group has floppy ears and white coat color. The second group has straight ears and black coat color. When you perform a cross of these two groups to obtain an F1 generation you see that all of your rabbits have floppy ears and grey coat color. Which of the following possibilities appears to be supported by what you see in the F1 generation?

Floppy ears are dominant over straight ears; coat color is determined by incomplete dominance.

Which of the following populations would you expect to have the most genetic diversity within the group?

A stock of tomato plants that is not true breeding

Which of the following is true of incomplete penetrance?

Gene interactions have been shown to result in incomplete penetrance in some cases.

Which of the following genotypes would result in a true-breeding stock?

AA or aa, but not Aa

A true breeding black rabbit is crossed with a true breeding white rabbit to produce an F1 generation with 8 individuals. If blending inheritance were true, which of the following would represent the expected phenotype of the F1 generation?

0 black rabbits, 0 white rabbits, 8 grey rabbits

What is an allele?

a different form of a gene

Animals that sexually reproduce are ________ and produce __________ gametes.

diploid; haploid

True or false: True breeding plants are typically heterozygous for most genes.

False

Which of the following represents the expected genotypes of an F2 generation consisting of 8 individuals from an initial cross of a true-breeding black (BB) rabbit and a true-breeding white (bb) rabbit?

8 progeny: 2 BB, 2 bb, 4 Bb

Which of the following represents the expected genotypes of an F1 generation consisting of 8 individuals from a cross of a true-breeding black (BB) rabbit and a true-breeding white (bb) rabbit?

0 BB, 0 bb, 8 Bb

You are given two populations of true-breeding tomato plants with two simple dominant/recessive traits that sort independently. Using the multiplication rule, how many different phenotypic combinations would you expect to see in the F2 generation? In what phenotypic ratio?

four, 9:3:3:1

A ____________ square is a useful diagram to show the results of a F1´ F1 cross.

punnett

You are given two populations of true-breeding tomato plants with two traits that sort independently. Using the multiplication rule, how many of the F2 progeny would you expect to have a recessive phenotype for both traits?

1/16

While doing a pedigree analysis of a royal family from the ancient Mayan empire, you notice that a prince with the genetic disease married a person from outside the royal family without a history of the disease in her family. Of their six children, two have the disease and four are not affected. The prince’s mother and his father also had this disease. If this disease is controlled by a single gene, then the most likely explanation for disease in the children would be:

the disease is dominant and is seen in heterozygous or homozygous dominant individuals.

The use of the multiplication rule requires which of the following?

The events being considered occur independently.

While doing a pedigree analysis of a European royal family, you notice a disease in a female child of two healthy parents. There are also some cousins with the same genetic disease. If this disease is controlled by a single gene, then the most likely explanation for these observations would be:

the disease is recessive and only seen in homozygous recessive individuals such as the daughter.

If the concept of blending inheritance were true, would variation increase or decrease over time?

decrease

____________ suggests that traits in offspring resemble the average of the parents.

Blending inheritance

A true breeding black rabbit is crossed with a true breeding white rabbit to produce an F1 generation of 8 individuals. If the black color trait is dominant, which of the following represents the expected phenotype of an F1 generation cross?

8 black rabbits, 0 white rabbits, 0 grey rabbits

The principle of independent assortment states that:

segregation of one set of alleles of a gene pair assort independently of another gene pair.

True or false: Environmental factors are unlikely to affect variable expressivity in individuals.

false

You are given two populations of true-breeding tomato plants with two traits that sort independently. Using the multiplication rule, how many of the F2 progeny would you expect to have a dominant phenotype for both traits?

9/16

A true breeding black rabbit is crossed with a true breeding white rabbit. If blending inheritance were true, which of the following would represent the expected phenotype of an F2 generation consisting of 8 individuals?

0 black rabbits, 0 white rabbits, 8 grey rabbits

In meiosis, the parent cell is ____________ and produces ____________ cells.

diploid; four haploid

A true breeding black rabbit is crossed with a true breeding white rabbit. If the black color trait is dominant, which of the following represents the expected phenotype of an F2 generation consisting of 8 individuals?

6 black rabbits, 2 white rabbits, 0 grey rabbits

Which of the following represents a problem with the concept of blending inheritance?

None of the other answer options is correct

Why was it important for Mendel to remove the anthers from pea plants in his experiments when crossing two different true-breeding pea plants?

to prevent self-fertilization

True or False:
Darwin believed that acquired characteristics are passed onto progeny.

True

True or False:
In Mendel’s experiments, his parental pea plants would be referred to as the F1 generation, and their progeny would

False

The addition rule requires which of the following?

More than one outcome (such as two different genotypes resulting in black fur) can occur simultaneously in an organism.

Two outcomes (such as having the genotype BB or Bb) are mutually exclusive in an organism.

Two outcomes (such as having the genotype BB or Bb) are mutually exclusive in an organism.

The principle of independent assortment states that:
segregation of one set of alleles of a gene pair assort with the alleles of another gene pair.
when gametes are formed, the two members of a gene pair assort together in gametes.
segregation of one set of alleles of a gene pair assort independently of another gene pair.
when gametes are formed, the two members of a gene pair will separate equally into gametes.

segregation of one set of alleles of a gene pair assort independently of another gene pair.

In a pedigree:
males are circles; females are squares.
females are circles; males are triangles.
males are squares; females are triangles.
females are circles; males are squares.
females are squares; males are triangles.
males are circles; females are triangles.

females are circles; males are squares.

Which of the following was not a characteristic that Mendel evaluated in pea plants?
leaf size
flower color
plant height
seed color
seed shape or texture

leaf size

A test cross of an organism of unknown genotype is done when the organism is crossed to an organism that is:
a heterozygote.
a dominant homozygote.
a recessive homozygote.
All of the answer options are correct.

a recessive homozygote.

Genes on different chromosomes ___________________ during meiosis. Genes that are very close together on the same chromosome are _________.

do not assort independently; linked
do not assort independently; unrelated
assort independently; linked
assort independently; unrelated

assort independently; linked

True or False:
Incomplete penetrance is synonymous with variable expressivity, as in both instances a trait may or may not be "expressed."

false

Mendel’s famous experiments were done using which plant?
pea plants
tomato plants
corn (maize)
artichokes

pea plants

A _________ square is a useful diagram to show the results of a F1 x F1 cross.
dominance
reciprocal
mendelian
punnett
genotype

punnett

You are given two true-breeding groups of rabbits. The first group has floppy ears and white coat color. The second group has straight ears and black coat color. When you perform a cross of these two groups to obtain an F1 generation you see that all of your rabbits have floppy ears and grey coat color. Which of the following possibilities appears to be supported by what you see in the F1 generation?

Straight ears are dominant over floppy ears; coat color is determined by intermediate dominance.
Straight ears are dominant over floppy ears; white coat color is dominant over black coat color.
Floppy ears are dominant over straight ears; white coat color is dominant over black coat color.
Straight ears are dominant over floppy ears; black coat color is dominant over white coat color.
Floppy ears are dominant over straight ears; black coat color is dominant over white coat color.
Floppy ears are dominant over straight ears; coat color is determined by incomplete dominance.

Floppy ears are dominant over straight ears; coat color is determined by incomplete dominance.

True or False:
Environmental factors are unlikely to affect variable expressivity in individuals.

False

A true breeding black rabbit is crossed with a true breeding white rabbit. If blending inheritance were true, which of the following would represent the expected phenotype of an F2 generation consisting of 8 individuals?
2 black rabbits, 2 white rabbits, 4 grey rabbits
0 black rabbits, 0 white rabbits, 8 grey rabbits
8 black rabbits, 0 white rabbits, 0 grey rabbits
6 black rabbits, 2 white rabbits, 0 grey rabbits
4 black rabbits, 2 white rabbits, 2 grey rabbits

0 black rabbits, 0 white rabbits, 8 grey rabbits

A true breeding black rabbit is crossed with a true breeding white rabbit to produce an F1 generation of 8 individuals. If the black color trait is dominant, which of the following represents the expected phenotype of an F1 generation cross?
8 black rabbits, 0 white rabbits, 0 grey rabbits
2 black rabbits, 2 white rabbits, 4 grey rabbits
0 black rabbits, 0 white rabbits, 8 grey rabbits
4 black rabbits, 2 white rabbits, 2 grey rabbits
6 black rabbits, 2 white rabbits, 0 grey rabbits

8 black rabbits, 0 white rabbits, 0 grey rabbits

A recessive trait is expressed when the genotype is _______________.
homozygous recessive or heterozygous
homozygous dominant or heterozygous
heterozygous only
homozygous dominant only
homozygous recessive only

homozygous recessive only

Recall that alleles of a single gene will segregate from one another during anaphase I. When do alleles for two different genes―located on two different chromosomes―segregate?
anaphase II
anaphase I
metaphase II
metaphase I
telophase I

anaphase I

Huntington’s disease is a devastating neurological disorder. If a child of an affected parent receives a copy of the Huntington allele, he or she will develop Huntington’s disease. Thus, Huntington’s disease could be considered _______________ trait.
a reciprocal
a neutral
either a neutral or recessive
a recessive
a dominant

a dominant

Animals that sexually reproduce are ________ and produce __________ gametes.
haploid; diploid
haploid; haploid
diploid; haploid
diploid; diploid

diploid; haploid

Genes that modify the expression of other genes show:
recessiveness.
epistasis.
incomplete dominance.
dominance.
blending inheritance.

epistasis.

True or False:
Each human gene only has two different alleles―one mutant allele and one "normal" allele.

False

Which of the following would not be considered an acquired trait?
leg amputation
muscle strength
eye color
scars
dyed hair color

eye color

If the phenotype of pea pod color is determined by incomplete dominance then you would expect the F2 generation from an original cross of true-breeding blue stock with true-breeding yellow stock to be:
67% green, 33% yellow.
25% yellow, 50% green, 25% blue.
67% blue, 33% yellow.
100% blue.
100% green.

25% yellow, 50% green, 25% blue.

Why was it important for Mendel to remove the anthers from pea plants in his experiments when crossing two different true-breeding pea plants?
to make sure self-fertilization would occur
to stimulate the pea plants to ovulate
to prevent self-fertilization
to protect the pea plants from environmental pollen

to prevent self-fertilization

You have an F2 generation derived from two true-breeding parents with different characteristics for the same trait (determined by a single allele). What percentage of the F2 generation with a dominant phenotype would you expect to be true breeding if they were self-fertilized?
33%
0%
25%
75%
67%
100%

33%

True or false:
Although Gregor Mendel’s work was not originally considered by his contemporaries to be groundbreaking, Mendel’s principles of segregation and independent assortment were "rediscovered" nearly two decades after his death.

True

If the concept of blending inheritance were true, would variation increase or decrease over time?
increase
decrease
stays the same

decrease

You have an F2 generation derived from two true-breeding parents (AA and aa) with different characteristics for the same trait (determined by a single allele). What percentage of the recessive phenotype would you expect to be true breeding if they were self-fertilized?
0%
33%
25%
100%
67%
75%

100%

where more than one gene controls pigment production, is an example of _______________ interactions between genes.
epistatic
dominant
variable expressivity
incomplete dominance
recessive

epistatic

Which of the following statements is true regarding Charles Darwin?
Darwin subscribed to the idea of blending inheritance, which posed problems to certain aspects of his work.
He believed that inheritance could be considered a homogenizing force.
He established the theory of natural selection.
He could not successfully synthesize the theory of blending inheritance with his theory of natural selection.
All of the answer options are correct.

All of the answer options are correct.

Which of the following statements is true regarding the yellow-seed pea plants of Mendel’s work?
Yellow-seed plants produce copious amounts of chlorophyll.
Yellow-seed plants have an enzyme that breaks down chlorophyll.
The yellow seed color of these plants is a recessive trait (compared to green seed color).
Yellow seeds in these plants only appear in the P1 generation, and never in the F1 generation.

Yellow-seed plants have an enzyme that breaks down chlorophyll.

The use of the multiplication rule requires which of the following?
The events being considered occur independently.
The events being considered are associated.

The events being considered occur independently.

The principle of independent assortment states that:

when gametes are formed, the two members of a gene pair will separate equally into gametes.
segregation of one set of alleles of a gene pair assort independently of another gene pair.
segregation of one set of alleles of a gene pair assort with the alleles of another gene pair.
when gametes are formed, the two members of a gene pair assort together in gametes.

segregation of one set of alleles of a gene pair assort independently of another gene pair.

True or False:
The Augustinian monk Gregor Mendel believed that organisms only passed on traits to their progeny―he had no concept of what genes were.

False

True or False:

True breeding stocks plants are typically heterozygous for most genes.

False

Which of the following statements are hallmarks of Mendel’s Laws?
Alleles of a given gene always segregate with alleles of other genes located anywhere on the same chromosome.
Two alleles of the same gene are normally inherited from the same parent.
The alleles of a given gene will segregate as gametes are formed.
All of the answer options are correct.

The alleles of a given gene will segregate as gametes are formed.

What is an allele?
the external appearance of an organism
a different forms of a gene
a spontaneous mutation
a group of unrelated genes seen in true breeding stock
a circular strand of DNA capable of self-replication

a different forms of a gene

True or False:

Traits correspond to a particular heritable unit. Mendel did not know about genes and DNA but he did realize there was some pattern of inheritance.

True

_______ thought things were related to blending inheritance. This idea was INCORRECT.

Darwin

_____- would do hybridization – he would cross (breed) two true breeding plants that had different traits. Successive breeding of the offspring revealed clear patterns of inherritence.

Mendel

Mendal studied huge populations of ______. The probabilities we calculate with Punnet squares would be unlikely to be observed in a small population, or in a group of four offspring. Peas have lots of offspring so they overcome this barrier.

Pea Plants

______ plants always exhibit the same traits. Pea plants usually self fertilize keeping them true breeding. Mendel altered the blossom structure and pollinated the plants himself in order to hybridize purple blossomed plants with white blossomed plants to find out what happened.

True breeding

_____ mixes the male gametes with the female gametes.

Pollination

The parental generation is called ____ . Subsequent generations are called Filial 1, Filial 2, or ____ for short.

P1, F1

A homozygous _____ plant crossed with a homozygous _____ plant will produce a _____ plant, but only the dominant trait will be observed in all the offspring.

dominant , recessive , heterozygous

True or False: Mendel articulated 3 laws of inheritance

True

______ one trait is dominant and will completely eclipse or overshadow the other recessive trait.

Dominance

_____ the alleles need to be separated into different gametes.

Segregation

No single gamete receives more than ____ allele/chromosome.

1

_____ are independently assorted. Do to crossing over and separation of sister chromatids randomly to the different gametes, the alleles are randomly and independently assorted. Traits/genes are not linked.

Alleles

Two things that aren’t completely true about mendel?

1)Some genes are linked and they will get crossed over together. 2)The law of dominance is also not completely true. While many genes are either dominant or recessive, there are also traits that exhibit incomplete dominance.

Calculating probabilities using mendelian genetics. Two Rules:

Multiplication rule and addition rule.

_____ are traits that are not independently assorted because crossing over is not random – some genes are close together and almost always crossed together as a unit.

Linked traits

____ is when one gene can impact the expression of a different gene.

Epistasis

Multiple alleles is when there are more than two copies of an allele for a ______

particular trait.

______ is when a genotype does not show up in the phenotype, even when the dominant gene is present. This is a yes or no situation. It either shows up or does not show up. Incomplete penetrance usually has some environmental component to gene expression.

Incomplete penetrance

______ means that a particular phenotype can be expressed in incremental units, or along a gradient. This not a yes or no situation, this is environmental controls on genotypic expression. For example, height has a genetic component but if you a malnourished, it can result in decreased height.

Variable expressivity