Unit 7 Biology

T/F: Autosomal recessive traits require two recessive alleles to demonstrate a phenotype.

T

T/F: The four main human ABO blood-types are encoded by three alleles.

T

heterozygous for a disorder

carrier

If an organism has two non-identical versions of a gene, the one that is expressed in the organism is called the _________ allele.

dominant

Which of the following is used to define a phenotypic characteristic resulting from the expression of two or more genes? polygenic inheritance pleiotropy incomplete dominance linked genes

polygenic inheritance

The ___________ is most commonly found in nature.

wild-type trait

In a dihybrid cross ratio, what is the probability of getting the genotype aa when you cross genotypes Aa and aa? 1/1 1/2 1/8 1/4

1/2

Round seeds (R) are dominant to wrinkled seeds (r), and yellow seeds (Y) are dominant to green seeds (y). What is the expected phenotypic ratio of a cross between an RrYy and an rryy individual? 1. 1:2:1 2. 9:3:3:1 3. 3:1 4. 1:1:1:1

1:1:1:1

A purebred plant that produces yellow seeds is crossed with a purebred plant that produces green seeds. The F1 plants have yellow seeds. What is the expected phenotypic ration of seed color of the offspring of an F1 X F1 cross? 1. 1:2:1 2. 2:2 3. 3:1 4. 9:3:3:1

3:1

A couple has two female children. What is the probability that their next child will be male?

50%

Polydactyly is a human characteristic in which a person has six fingers per hand. The trait for polydactyly is dominant over the trait for five fingers. If a man who is heterozygous for this trait marries a woman with the normal number of fingers, what are the chances that their child would be polydactyl? 1. 0% 2. 25% 3. 50% 4. 100%

50%

Which of these crosses will only produce heterozygous offspring? 1. AA x aa 2. AA x Aa 3. Aa x Aa 4. Az x aa

AA x aa

"A" represents the dominant allele and "a" represents the recessive allele of a pair. If, in 1,000 offspring, 500 are aa and 500 are of some other genotype, which of the following are most probably the genotypes of the parents? 1. Aa and Aa 2. Aa and aa 3. AA and aa 4. aa and aa

Aa and aa

Surprising new evidence has shown that, in some cases, environmental factors can modify chromosomes in such a way that changes the expression of genes without changing genes themselves or any part of the DNA sequence. These modifications are called epigenetic effects. Epigenetic effects can sometimes even be passed from generation to generation. In what way would this kind of "inheritance" be an exception to Mendel's laws? Mendel's laws apply only to pea plants, not all sexually reproducing organisms. According to Mendel's laws, the effects of our environment are not passed on to the next generation. Since they are scientific laws, Mendel's laws can't be violated even if there is new evidence to the contrary. These effects must be caused by mutations.

According to Mendel's laws, the effects of our environment are not passed on to the next generation.

The recombination frequency between gene B and gene C is 11%. The recombination frequency between gene B and gene D is 15%. What would be the arrangement of these genes on a linkage map? 1. CDB 2. DBC 3. BCD 4. more information is needed

DBC

The recombination frequency between gene B and gene C is 11%. The recombination frequency between gene B and gene D is 5%. The recombination frequency between gene C and gene D is 15%. What would be the arrangement of these genes on a linkage map? BCD CDB DBC More information is needed.

DBC

In humans, the presence or absence of dimples is a trait controlled by a single gene. What is the genotype of an individual who is heterozygous for dimples? dd Dd DD DI

Dd

(referring to birth of a child with blood type A to a mother with blood type B) : the father must have the following blood type(s)? 1. Either AB or A 2. Either AB or B 3. Either AB or O 4. AB or A or O

Either AB or A

T/F: All mutations are harmful.

F

T/F: Dominant traits are always the most likely version of a gene in a population.

F

T/F: Every trait is determined by a single pair of alleles.

F

T/F: If a couple as a "one-in-four" risk of having a child with a disease, and their first born has the disease the next child will have a reduced risk of having the disease.

F

T/F: Pink colored flower petals generated from the cross of purebred red petal and pure bred white petal flowers demonstrate one example of co-dominance.

F

T/F: Traits are determined by genes and personality.

F

An individual with the genotype AaBb produces four different gametes in equal proportions. This is a demonstration of _________. 1. the chromosomal theory of inheritance 2. Mendel's law of independent assortment 3. linkage 4. Mendel's principle of segregation

Mendel's law of independent assortment

Which of the following statements is correct? A genetic cross produces the P generation. Mendel's pea plants could cross-fertilize but not self-fertilize. True-breeding plants are able to produce a variety of flower colors when self-fertilized. Offspring of two different true-breeding varieties are called hybrids.

Offspring of two different true-breeding varieties are called hybrids.

You cross a true-breeding red-flowered snapdragon with a true-breeding white-flowered snapdragon. All of the F1 are pink. What can you say about the alleles for the parental traits? Red and white show incomplete dominance. Red is dominant. Both red and white are recessive. Pink is dominant, whereas red and white are recessive.

Red and white show incomplete dominance.

What is the basis of Mendel's laws? 1. The behavior of chromosomes during prophase I and of meiosis only 2. The behavior of chromosomes during mitotic anaphase 3. The behavior of chromosomes during prophase I and prophase II of meiosis 4. The behavior of chromosomes during metaphase I and anaphase

The behavior of chromosomes during metaphase I and anaphase

Assume you were studying two characteristics of peas, and when you crossed heterozygous F1 individuals you did not see the 9:3:3:1 ratio predicted for a dihybrid cross. You later found that these two characteristics were on the same chromosome. With this information, how would you explain the results? There must have been a mutation. The genes are linked and are inherited together. The genes must be on the sex chromosomes. The results can be explained as polygenic inheritance.

The genes are linked and are inherited together.

What is the key to the recognition of incomplete dominance? The heterozygote expresses the phenotype of both homozygotes. The trait exhibits a continuous distribution. The phenotype of the heterozygote falls between the phenotypes of the homozygotes. The alleles affect more than one trait.

The phenotype of the heterozygote falls between the phenotypes of the homozygotes.

What is the key to recognition of a trait whose expression is determined by the effects of two or more genes (polygenic inheritance)? 1. A mating between a homozygous and heterozygous individual produces more than the expected number of offspring expressing the dominant trait 2. All of the alleles of the gene for that trait are equally expressed 3. Pleiotropy occurs 4. The trait varies along a continuum in the population

The trait varies along a continuum in the population

In peas, the trait for tall plants is dominant (T) and the trait for short plants is recessive (t). The trait for yellow seed color is dominant (Y) and the trait for green seed color is recessive (y). A cross between two plants results in 296 tall yellow plants and 104 tall green plants. Which of the following are most likely to be the genotypes of the parents? 1. TtYY x Ttyy 2. TTyy x TTYy 3. TtYy x TtYy 4. TtYy x TTYy

TtYy x TTYy

Using recombination data, it is possible to determine the location of genes on a chromosome. The result is _____. linked genes a pedigree a linkage map a carrier

a linkage map

A form of vitamin D-resistant rickets, known as hyphosphatemia, is inherited as an X-linked dominant trait. If a male with hyphosphatemia marries a normal female, which of the following concerning their potential offspring would be true? 1. all of their sons would inherit the disease 2. all of their daughters would inherit the disease 3. about 50% of the sons would inherit the disease 4. about 50% of the daughters would inherit the disease

all of their daughters would inherit the disease

Most human genes come in alternate versions called _______.

alleles

Linked genes are genes that __________. are on the same chromosome govern traits (such as hair texture and hair color) that are functionally related have the same alleles residing on them reside on the sex chromosomes

are on the same chromosome

Linked genes are genes that __________. are on the same chromosome have the same alleles residing on them reside on the sex chromosomes govern traits (such as hair texture and hair color) that are functionally related

are on the same chromosome

An individual who is homozygous ___________. 1. expresses the dominant trait 2. carries two different copies for a gene 3. carries two copies of the same allele for a gene 4. expresses the recessive trait

carries two copies of the same allele for a gene

A ___________ is an inherited feature that varies from individual to individual.

character

An individual with the blood group genotype L^MLN has the phenotype MN. What is the relationship between L^M and L^N alleles? 1. incomplete dominane 2. pleiotropy 3. L^ is dominant 3. co-dominance

co-dominance

The most common lethal genetic disease in the United States is _____. Huntington's disease sickle-cell disease cystic fibrosis hemophilia

cystic fibrosis

A cross between two individuals with black eyes and green skin which results in an individual with orange eyes and white skin is an example of a _____ cross. difficult trihybrid dihybrid monohybrid test

dihybrid

version of a gene that exhibits its phenotype when expressed

dominant allele

According to Mendel's law of segregation, __________. 1. two alleles segregate into each gamete 2. more gametes carrying the dominant allele are produced than gametes carrying the recessive allele 3. gametes have one copy of each allele 4. gametes are diploid

gametes have one copy of each allele

The scientific study of heredity is called _____. heredity true-breeding breeding genetics

genetics

The _____________ is the genetic makeup of an organism.

genotype

inherited DNA sequence for a trait found in a cell

genotype

Red-green color blindness is inherited as a sex-linked recessive trait. The gene is found on the X chromosome. How can a man with normal color vision father a daughter who is red-green color blind? 1. the woman with whom he mates is red-green color-blind 2. the man is heterozygous for red-green color blindness 3. he can't (unless there is a mutation) 4. the man's mother carries an allele for red-green color blindness, and the expression of the trait skipped a generation

he can't (unless there is a mutation)

In humans, the inheritance of ___________ is best explained as being polygenic. 1. cystic fibrosis 2. height 3. blood type 4. sickle-cell disease

height

Mendel crossed purebred purple-flowered plants with purebred white-flowered plants, and all of the resulting offspring produced purple flowers. The offspring are all ______, and the allele for purple flowers is ______. heterozygotes... recessive homozygotes... dominant heterozygotes... dominant homozygotes... recessive

heterozygotes... dominant

A plant with the genotype AABbcc is __________. homozygous for two different genes heterozygous for two different genes triploid recessive for three different genes

homozygous for two different genes

A plant with the genotype AABbcc is __________. recessive for three different genes triploid heterozygous for two different genes homozygous for two different genes

homozygous for two different genes

A mating between a purebred purple-flowered pea plant and a purebred white-flowered pea plant would produce a(n) _____________. 1. purebred variety 2. hybrid 3. P generation 4. F2 generation

hybrid

offspring of two purebred organisms

hybrid

An individual with (naturally) curly hair and an individual with (naturally) straight hair mate; all of their offspring have (naturally) wavy hair. What is the relationship between the alleles for hair texture?

incomplete dominance

heterozygous phenotype is a mixture

incomplete dominance

Mendel believed that the characteristics of pea plants are determined by the... 1. inheritance of units or factors from both parents 2. inheritance of units from one parent 3. relative health of the parent plants at the time of pollination 4. relative frequency of mutations

inheritance of units or factors from both parents

Genes for two different traits that are located next to each other on the same chromosome would most likely be... 1. inherited separately 2. co-dominant 3. inherited together 4. incompletely dominant

inherited together

To determine the phenotype of an individual who expresses a dominant trait, you would cross that individual with an individual who ___________. 1. expresses the dominant trait 2. is homozygous dominant for that trait 3. is homozygous recessive for that trait 4. is heterozygous for that trait

is homozygous recessive for that trait

What is the best explanation for a BbCc x bbcc cross producing offspring in a 5:5:1:1 phenotypic ratio? 1. linked genes 2. polygenic inheritance 3. incomplete dominance 4. co-dominance

linked genes

region of a chromosome that contains a gene

locus

A genetic cross involving parents that differ in a single character is called a __________ ___________.

monohybrid cros

The ABO blood group in humans is an example of __________ producing four phenotypes. people with genetic disorders pleiotropy multiple alleles polygenic inheritance

multiple alleles

The ABO blood group in humans is an example of __________ producing four phenotypes. people with genetic disorders polygenic inheritance multiple alleles pleiotropy

multiple alleles

Incomplete dominance is a condition in plants and people where __________. offspring have an appearance in between the phenotypes of the two parents a single gene impacts more than one characteristic multiple alleles are responsible for an inheritance pattern most heritable diseases arise

offspring have an appearance in between the phenotypes of the two parents

Which statement describes how two organisms may show the same trait, yet have different genotypes for that phenotype? 1. one is homozygous dominant and the other is heterozygous 2. both are heterozygous for the dominant trait 3. one is homozygous dominant and the other is homozygous recessive 4. both are homozygous for the dominant trait

one is homozygous dominant and the other is heterozygous

The physical traits of an organism are called its _______________.

phenotype

Marfan syndrome is the result of inheriting a single allele. Individuals with Marfan syndrome are tall and long-limbed, and have both cardiovascular and eye defects. The inheritance of Marfan syndrome is an example of _________. 1. co-dominance 2. a recessive disorder 3. pleiotropy 4. incomplete dominance

pleiotropy

If an organism has two non-identical versions of a gene, the one that is not expressed in the organism is called the ____________ allele.

recessive

version of a gene whose phenotypic presence may be masked

recessive allele

The percentage of recombinant phenotypes resulting from fertilization involving recombinant gametes is called _____. a linkage map genetic recombination mitosis recombination frequency

recombination frequency

The best definition of a purebred plant is one that __________. 1. cannot be cross-fertilized 2. self-fertilizes to produce hybrid offspring 3. produces sterile offspring when cross-fertilized 4. self-fertilizes to produce offspring identical to the parent

self-fertilizes to produce offspring identical to the parent

Traits controlled by genes on the X-chromosome are said to be... 1. homozygous 2. sex-linked 3. incompletely dominant 4. mutagenic

sex-linked

(referring to birth of a child with blood type A to a mother with blood type B) : If the father has blood type AB, which of the following statements is correct about the mother? 1. she contributes an I^B allele, which is recessive to the father's I^A allele 2. she contributes an i allele, which is recessive to the father's I^A allele 3. she contributes an I^B allele, which is co-dominant to the father's I^A allele 4. she contributes an i allele, which is co-dominant to the father's I^B allele

she contributes an i allele, which is recessive to the father's I^A allele

Modern advances in __________ have provided important insights into the evolutionary history of life on Earth. constructing evolutionary trees technology dog breeding research on human subjects

technology

A ______ is one particular variation of a character.

trait

detectable variant expressed by a specific gene

trait

The most common phenotype in a natural population is referred to as the _____. genotype autosome mutant phenotype wild type

wild type