Module #8 Review Questions

Question 1

What term is used if an organism has a certain characteristic that is always passed on to its offspring we say that this organism bred true with respect to that characteristic?

Answer 1

True Breeding

Question 2

What is one of a pair of genes that occupies the same position on homologous chromosomes?

Answer 2

Allele

Question 3

What is an allele that will not determine the phenotype unless the genotype is homozygous in that allele?

Answer 3

Recessive allele

Question 4

What is a cross between two individuals, concentrating on only one definable trait?

Answer 4

Monohybrid cross

Question 5

What is a cross between two individuals, concentrating on two definable traits?

Answer 5

Dihybrid cross

Question 6

What is the inheritance of a genetic trait not on a sex chromosome?

Answer 6

Autosomal inheritance

Question 7

There are four principles in Mendal’s updated terminology, name all four of them.

Answer 7

1. The traits of an organism are determined by its genes
2. Each organism has two alleles that make up the genotype for a given trait
3. In sexual reproduction, each parent contributes only one of its alleles to its offspring.
4. In each genotype, there is a dominant allele. If it exists in an organism, the phenotype is determined by that allele.

Question 8

A diagram that follows a particular phenotype through several generations is call ___.

Answer 8

A pedigree

Question 9

Some traits are sex-linked, which means the alleles that define those traits are found where?

Answer 9

On the Sex chromosomes

Question 10

Chromosomes that do not determine the sex of an individual are called what?

Answer 10

Autosomes

Question 11

Many traits are caused by the interaction of several genes. This is called what?

Answer 11

Polygenetic inheritance

Question 12

What is the term that means the alleles tend to “mix” rather than one dominating the other?

Answer 12

Incomplete dominance

Question 13

In some cases, one set of alleles might affect how another set of alleles is expressed. What is this called?

Answer 13

Epistasis

Question 14

What is it called when a single gene can affect multiple observable traits?

Answer 14

Pleiotrophy

Question 15

The human gene for blood type which has A, B, and O alleles is an example of what kind of alleles.

Answer 15

Multiple

Question 16

In blood type, A and B are dominant over O but not dominant over each other, this is an example of what?

Answer 16

Codominance

Question 17

When an antigen is introduced into the blood, the body’s response is to produce what?

Answer 17

An Antibody

Question 18

The “+” and “-“in the blood type refers to the what, which is controlled by a single gene with two alleles?

Answer 18

Rh factor

Question 19

The “+” and the “-“ refer to the RH factor in the blood. Which allele is dominant?

Answer 19

“+”

Question 20

The “+” and the “-“ refer to the RH factor in the blood. Which allele is recessive?

Answer 20

“-“

Question 21

In Mendal’s experiments, he determined that the allele for tallness (we’ll call it “T”) is dominant whereas the allele for shortness (we’ll call it “t”) is recessive. Let’s suppose a homozygous tall pea plant was crossed with a heterozygous pea plant. What will be the genotype and phenotypes of the offspring?

Answer 21

50% will have the genotype TT while 50% have the genotype Tt. 100% will have the phenotype of being tall.

Question 22

he allele for a pea plant to produce yellow peas(Y) is dominant over the allele for green peas (y). A heterozygous pea plant is crossed with a pea plant that produces green peas. What is the percent chance of each genotype and phenotype produced by this union?

Answer 22

50% will be Yy and will make yellow peas, while 50% will be yy and will make green peas.

Question 23

In Pea plants tallness is a dominant genetic trait if “T” represents the dominant allele and “t” represents the recessive allele, what are the possible genotypes for a plant is tall.

Answer 23

TT, Tt

Question 24

A woman is heterozygous in the ability to roll her tongue when extended. If she marries a man who cannot roll his tongue, what percentage of their children will be able to roll their tongues? Remember, the allele for being able to roll your tongue is dominant.

Answer 24

50% of the children will be able to roll their tongues.

Question 25

For a given trait, how many alleles does a normal gamete have?

Answer 25

One allele for each trait. That way, when two gametes fertilize each other the zygote will have two alleles for each trait.

Question 26

For a given trait, how many alleles does a non-gamete cell have?

Answer 26

Two alleles

Question 27

From experiment 8.3 what percentage of the girls will have the disease?

Answer 27

0% of the girls will have the disease

Question 28

From experiment 8.3. What percentage of the boys will have the disease?

Answer 28

50% of the boys will have the disease.

Question 29

Eye color in fruit flies is a sex-linked trait. Red (R) is dominant; while white (r) is recessive. If a red-eyed male and a white-eyed female are crossed, what percentage of males and females are red-eyed?

Answer 29

100% female are red eyed and 100% males are white eyed.

Question 30

A genetic abnormality that is passed through the autosomes is called what?

Answer 30

Autosomal inheritance

Question 31

A genetic abnormality is passed through the sex chromosomes is called what?

Answer 31

Sex-linked inheritance

Question 32

When one of the alleles of a gene is chemically changed this is called what?

Answer 32

Allele mutation

Question 33

What is a situation in which a chromosome loses or gains genes during meiosis?

Answer 33

Change in the chromosome structure

Question 34

hat is a situation in which a cell can wind up with too many or too few of a specific chromosome.

Answer 34

Change in the chromosome number

Question 35

In pea color and pea texture, yellow (Y) is dominant and green (y) is recessive. In addition, smooth peas (S) are dominant and wrinkled peas (s) are recessive. A pea plant that produces green peas and is heterozygous in pea texture is crossed with a plant that is heterozygous in pea color and produces wrinkled peas. What are the percentages of the phenotypes in the offspring?

Answer 35

25% will produce yellow, smooth peas, 25% willproduce yellow, wrinkled peas, 25% will produce green, smooth peas, and 25% will produce green, wrinkled peas.

Question 36

In a pedigree both parents can roll their tongue and produce 3 offspring that can roll their tongue and one that cannot. What is the dominant trait?

Answer 36

Able to roll the tongue

Question 37

n a pedigree both parents can roll their tongue and produce 3 offspring that can roll their tongue and one that cannot. What are the genotype of the parents?

Answer 37

the inability to roll the tongue is recessive. Both of the first parents (1 and 2) must be Rr and Rr. 3 must be rr,4 is Rr

Question 38

A man that has A+ blood and is heterozygous in each allele marries a woman whose blood is AB-. What are the possible blood types for their children, along with the percentage chance of each?

Answer 38

25% of the children will have A+ blood, 25% of the children will be A-, 12.5% will be AB+, 12.5% will be AB-, 12.5 will be B+ and 12.5% will be B-