Biology Chapter 11: The First Geneticist: Mendel And His Discoveries

Front 1

One of the alternative forms of a single gene.

Back 1

allele

Front 2

A distribution of values that is symmetrically largest around the average.

Back 2

bell curve

Front 3

A condition in which two alleles of a given gene have different phenotypic effects, with both effects manifesting in organisms that are heterozygous for the gene.

Back 3

codominance

Front 4

To pollinate one plant with pollen of another plant.

Back 4

cross-pollinate

Front 5

An experimental cross in which the plants used differ in two of their characters.

Back 5

dihybrid cross

Front 6

Term used to designate an allele that is expressed in the heterozygous condition.

Back 6

dominant

Front 7

The offspring of the parental generation in an experimental cross.

Back 7

first filial generation (F1)

Front 8

The genetic makeup of an organism, including all the genes that lie along its chromosomes.

Back 8

genotype

Front 9

Possessing two different alleles of a gene for a given character.

Back 9

heterozygous

Front 10

Having two identical alleles of a gene for a given character.

Back 10

homozygous

Front 11

A genetic condition in which the heterozygote phenotype is intermediate between either of the homozygous phenotypes.

Back 11

incompletely dominant

Front 12

During gamete formation, gene pairs assort independently of one another. Also known as Mendel's Second Law, this is one of the principles of inheritance formulated by Gregor Mendel.

Back 12

law of independent assortment

Front 13

Differing characters in organisms result from two genetic elements (alle-les) that separate in gamete formation, such that each gamete gets only one of the two alleles. Also known as Mendel's First Law, this is one of the principles of inheritance formulated by Gregor Mendel.

Back 13

law of segregation

Front 14

An experimental cross in which organisms are tested for differences in one character.

Back 14

monohybrid cross

Front 15

Three or more alleles—alternative forms of a gene—occurring in a population.

Back 15

multiple alleles

Front 16

The generation that begins an experimental cross between organisms. Such a cross is used to study genetics and heredity of traits.

Back 16

parental generation (P)

Front 17

A physical function, bodily characteristic, or action of an organism.

Back 17

phenotype

Front 18

The phenomenon by which one gene has many effects.

Back 18

pleiotropy

Front 19

Inheritance of a genetic character that is determined by the interaction of multiple genes, with each gene having a small additive effect on the character.

Back 19

polygenic inheritance

Front 20

Term used to designate an allele that is not expressed in the heterozygous condition.

Back 20

recessive

Front 21

In probability theory, the principle that, when an outcome can occur in two or more different ways, the probability of that outcome is the sum of the respective probabilities.

Back 21

rule of addition

Front 22

In probability theory, the principle that the probability of any two events happening is the product of their respective probabilities.

Back 22

rule of multiplication

Front 23

Alternate forms of a gene that govern the expression of the same trait and that occur at the same positions on homologous chromosomes are called .

chromatids.
gametes.
alleles.
mRNA.
autosomes.

Back 23

alleles

Front 24

A diploid cell with four total chromosomes is heterozygous at 10 different genes. Do these genes assort independently during meiosis?

Not enough information is given to determine if the genes assort independently.
No.
Yes.

Back 24

no

Front 25

In Mendel's garden peas, the tallness (T) trait is dominant over the dwarf condition (t), round seed (R) is dominant to wrinkled seeds (r), purple flowers (P) are dominant to white flowers (p), and one-pod seeds (S) are dominant to three-pod seeds (s). These genes are all located on separate chromosomes. Suppose a plant heterozygous for each gene is self-fertilized, and 1,000 offspring are produced.

How many would Mendel have expected to be dwarf with purple flowers and wrinkled one-pod seeds? (level 1). [Hint]

35
9
1,000
562
6

Back 25

35

Front 26

For codominant genes, the standard procedure of using capital and lowercase letters for the different alleles is inadequate. For codominant genes, a superscript is used. For example, the human blood type A allele is indicated as "IA" and the Type B allele is indicated as "IB." The recessive allele that is responsible for Type O blood is still given the lowercase letter "i." In a family of six children, two are blood Type O, two are blood Type AB, one is blood Type B, and another Type A. What are the possible genotypes of the parents?

IAIB x ii
IAi x IAIB
IBi x IAIB
IAi x IBi
IAIB x IAIB

Back 26

IAi x IBi

Front 27

The fact that all seven of the garden pea traits studied by Mendel obeyed the principle of independent assortment means that ...

garden pea plants have seven pairs of chromosomes.
seven pairs of alleles determining these traits are on the same pair of homologous chromosomes.
seven pairs of alleles determining these traits behave as if each is on separate chromosome pairs.
garden pea plants produce gametes with seven chromosomes.

Back 27

seven pairs of alleles determining these traits behave as if each is on separate chromosome pairs.

Front 28

In an individual with genotype AaBbCcDDEe, what proportion of the gametes produced will have an "A" allele?

9/16
1/2
3/4
1/4

Back 28

1/2

Front 29

Assuming no gene interactions, a cross between two heterozygous individuals (AaBb) at two independently assorting genes will produce an expected phenotypic ratio of ...

9:3:3:1.
1:1:1:1.
3:1.
15:1.
1:2:1.

Back 29

9:3:3:1.

Front 30

A cross between two heterozygous individuals (AaBb) at two independently assorting incompletely dominant genes will produce an expected phenotypic ratio of ...

1:2:1.
1:2:2:4:1:2:1:2:1.
15:1.
9:3:3:1.
1:1:1:1.

Back 30

1:2:2:4:1:2:1:2:1.

Front 31

You have become a renowned marine biologist, and in your travels you discover a species of fish that is diploid and reproduces exactly like other sexually reproducing animals with the exception that this animal is hermaphroditic (it has both male and female reproductive organs and can self-fertilize). You mate two fish, and then raise one of their offspring and allow it to self-fertilize, producing hundreds of offspring. Which of the following would be true of the offspring of this individual?

They would have completely different genes from their parent, but would be phenotypically identical.
They would have the same alleles as their parent, but they would be shuffled into different combinations, resulting in phenotypically different offspring.
They would be phenotypically identical to their parent.

Back 31

identical.
They would have the same alleles as their parent, but they would be shuffled into different combinations, resulting in phenotypically different offspring.

Front 32

In another species of flowering plant, the tallness (T) trait is dominant over the dwarf condition (t), and red flowers (R) are dominant to white flowers (r). Suppose a plant heterozygous for both genes is crossed with an individual that is homozygous recessive for each trait. The cross produces a 1:1:1:1 phenotypic ratio. Are these two genes located on separate homologous pairs?

Yes, the cross TtRr x ttrr would give us an expected 1:1:1:1 phenotypic ratio if the genes assorted independently.
No, if the two genes were on separate chromosomes, then we would expect something other than a 1:1:1:1 phenotypic ratio.
No, if the two genes were on separate chromosomes, then we would expect a 9:3:3:1 ratio.

Back 32

Yes, the cross TtRr x ttrr would give us an expected 1:1:1:1 phenotypic ratio if the genes assorted independently.

Front 33

For Mendel's pea plants, tall (T) was dominant over dwarf (t), and purple flowers (P) were dominant over white flowers (p). Assuming that these genes would sort independently, how many different types of gametes would be produced in a plant with the genotype TtPP?

4
3
8
2

Back 33

2

Front 34

For Mendel's pea plants, tall (T) was dominant over dwarf (t), and purple flowers (P) were dominant over white flowers (p). A plant with genotype the ttPp would have which phenotype?

dwarf plant with purple flowers
tall plant with purple flowers
tall plant with white flowers
dwarf plant with white flowers

Back 34

dwarf plant with purple flowers

Front 35

For Mendel's pea plants, tall (T) was dominant over dwarf (t), and purple flowers (P) were dominant over white flowers (p). If a plant with the genotype ttPp were crossed with a plant that was Ttpp, the phenotypic ratio of the offspring would be ...

3:1.
9:1.
9:3:3:1.
1:1:1:1.

Back 35

1:1:1:1.

Front 36

For Mendel's pea plants, tall (T) was dominant over dwarf (t), and purple flowers (P) were dominant over white flowers (p). A plant that had a phenotype of dwarf plant and white flowers had which genotype?

ttpp
TTpp
TtPp
ttPP

Back 36

ttpp

Front 37

For Mendel's pea plants, tall (T) was dominant over dwarf (t), and purple flowers (P) were dominant over white flowers (p). A plant that had a phenotype of tall plant and purple flowers must have had which genotype?

TtPP
TtPp
TTPp
The genotype cannot be deduced from the phenotype.

Back 37

The genotype cannot be deduced from the phenotype.

Front 38

A mother who is heterozygous for blood Type A states that a man who is heterozygous for blood Type B is the father of her baby. What blood type must the baby have if the man is indeed the baby's father?

Type O
Type B
Type AB
Type A
All the above are possible blood types for the baby.

Back 38

All the above are possible blood types for the baby.

Front 39

For the Punnett square, the genotype of parent 1 is ______ while that of parent 2 is ______.

Aa / Aa
aa / aa
AA / aa
Aa / aa

Back 39

Aa / aa

Front 40

On their wedding day, a man and wife decide that they want to have three daughters. What is the probability that this will actually occur?

1/8
1/4
1/2
1/16

Back 40

1/8

Front 41

A plant with orange flowers is crossed with another plant with orange flowers. The offspring show the phenotypic ratio of one red flower:two orange flowers:one yellow flower. These plants are displaying a classic example of ...

pleiotropy.
incomplete dominance.
codominance.
multiple alleles.

Back 41

incomplete dominance.

Front 42

A trait, such as skin color, that is coded for by more than one gene is an example of ...

codominance.
incomplete dominance.
polygenic inheritance.
pleiotropy.

Back 42

polygenic inheritance.

Front 43

The first filial generation, or F1 results when

two P generation organisms are crossed
the progeny of a P generation is crossed
a P generation is crossed with an F2 organism
an F3 organism is crossed with an F2 organism
both a and d

Back 43

two P generation organisms are crossed

Front 44

When Mendel crossed pure-bred yellow peas with pure-bred green peas, the F1 generation contained

all yellow peas
all green peas
green and yellow peas
green, wrinkled peas
both b and d

Back 44

all yellow peas

Front 45

A very important characteristic of the garden peas used by Mendel was that

Each trait examined had more than two different varieties.
The F1 generation always resulted in a 1:1 phenotypic ratio.
All crosses resulted in a 1:3 genotypic ratio.
The plants had the ability to self-fertilize.
All yellow peas had the same genotype.

Back 45

The plants had the ability to self-fertilize.

Front 46

If a cross is made between a pure-breeding green, round (yyRR) plant, and a pure-breeding yellow, wrinkled (YYrr) plant, what is the result?

all yellow, round peas
all green, wrinkled peas
all yellow, wrinkled peas
yellow wrinkled; green wrinkled
none of the above

Back 46

all yellow, round peas

Front 47

If plants in a cross have the following genotypes (YYRr x yyRr) the correct term for the type of cross is:

recessive cross
codominant cross
monohybrid cross
dihybrid cross
dominant cross

Back 47

dihybrid cross

Front 48

Mendel’s first law states:

During the formation of gametes, genetic elements (alleles) segregate from each other.
The probability of any two events happening is the product of their respective probabilities.
Mendel did not write any laws regarding genetics.
During the formation of gametes, gene pairs demonstrate independent assortment.
If an organism is pure-breeding for any trait, it will display incomplete dominance.

Back 48

During the formation of gametes, genetic elements (alleles) segregate from each other.

Front 49

In the ABO blood system in human beings, alleles coding for the A and B proteins are codominant, while the O allele is recessive. In a paternity dispute, a type AB woman claimed that one of four men was the father of her type A child. Which of the following men could be the father of the child on the basis of the evidence given?

type AB
type O
type A
type B
any of them

Back 49

any of them

Front 50

Mendel’s second law states that

No organism can have more than two alleles for a given character.
Gene pairs assort independently of one another during gamete formation.
No two organisms can ever be genetically identical.
Organisms will tend to be heterozygous for most traits, rather than homozygous.
The way one gene pair assorts during gamete formation will affect the way other gene pairs assort.

Back 50

Gene pairs assort independently of one another during gamete formation.

Front 51

Which of the following is true about polygenic inheritance?

Its outcomes are always predictable.
It produces phenotypes that grade smoothly into one another.
It is the exception rather than the rule in living things.
It is never seen in human beings.
It produces only homozygous individuals.

Back 51

It produces phenotypes that grade smoothly into one another.

Front 52

Which of the following is true regarding the effects of genes and environment on phenotypic variation?

Gene expression is not affected by a change in environment.
Phenotypes are based only on environmental influences.
The phenotypes of genetically identical organisms may vary in different environments.
Environment may easily affect genotype, not phenotype.
Gene expression will always be greatest in the native environment.

Back 52

The phenotypes of genetically identical organisms may vary in different environments.