Chapter 10 Biology Smartbook
A diploid cell has ____ alleles for each gene, one on each homologous chromosome.
2
In the monohybrid cross between yellow-seeded F1 plants (YY x Yy) shown in the image, about what precent of the F2 generation will show the recessive phenotype of green seeds?
25%
What percent chance is there of producing an offspring with the yy genotype in the Punnett square shown?
25%
In a monohybrid cross, Mendel mated two F1 generation (Yy) pea plants. What was the genotypic ratio in the F2 generation?
25% YY, 50% Yy, 25% yy
What percent chance is there of producing an offspring with the yellow seed color phenotype in the Punnett square shown?
75%
Select all of the plants that are true-breeding when they self-fertilize.
A and B
In the human genome, 22 of the 23 pairs of chromosomes are called
Autosomes.
Select the hybrid plant, which produces a mixture of offspring when it self-fertilizes.
C
Select all of the advantages of studying heredity with the pea plant Pisum sativum over another species.
Can self-fertilize Many traits with two distinguishable forms Produces many offspring Develops quickly Can cross-fertilize
The exchange of genetic material between homologous chromosomes during prophase | of meiosis is called _________ and can explain the appearance of _________ in the offspring.
Crossing over; recombinant traits
In Mendel's studies, a ______ trait is one that could mask the appearance of another trait.
Dominant
When one or both copies of a gene are the ______ allele, then is allele's form of the trait will be exhibited.
Dominant
An individual's allele combination for a particular gene is called the _______.
Genotype
The genotype of a heterozygous individual is ____, of a homozygous dominant is ____, and of a homozygous recessive individual is ____.
Gg; GG; gg
Who discovered how to calculate probabilities of inheritance primarily using traits of pea plants?
Gregor Mendel
In Mendel's experiments, the hybrid plants had what genotype?
Heterozygous
Select all of the possible genotypes for the true-breeding plants in Mendel's experiments.
Homozygous dominant Homozygous recessive
Which of the following represents a monohybrid cross?
YY x Yy
Alternative forms of a gene are called ______.
alleles
In the cookbook analogy of chromosomes, ______ are like the variable options for a particular recipe, which represents a gene.
alleles
Of the 23 pairs of human chromosomes, the 22 pairs of chromosomes that are the same in both sexes and are not sex chromosomes are called the
autosomes
Match the symbols to the correct allele combination description.
ee: homozygous recessive JJ: homozygous dominant Bb: heterozygous
The haploid cells of humans are called
gametes.
If a chromosome is like a cookbook, then a recipe in the cookbook is like a _______, which contains the information to synthesize a protein.
gene
What is a sequence of DNA nucleotides that holds the instructions to make a protein?
gene
Referring to this linkage map image, what pair of genes has the highest crossover frequency?
genes V and W
The _______ is the combination of alleles an individual has for a particular gene.
genotype
A cell with one set of chromosomes is a(n) ______ cell.
haploid
Gametes, or sex cells, are _______, meaning they contain only one set of chromosomes.
haploid or haploid cells
A(n) ______ individual has 2 different alleles for a given gene.
heterozygous
If parents contribute different versions of a gene, then the offspring are ________ for that gene.
heterozygous
Two chromosomes that look alike and have the same sequence of genes in the same positions are a(n) _____ pair.
homologous
A _______ individual has two identical alleles for a gene.
homozygous
If both parents contribute identical versions of a gene, then the offspring are _____ for that gene.
homozygous
Homologous chromosomes contain the same genes but may contain different alleles at a particular site, called a gene
locus.
A ______ cross is a mating between two individuals that are both heterozygous for the same, single, gene.
monohybrid
An example of a(n) _____ cross is the mating of two rats that both contain the alleles Ff for fur color. This cross is made to examine which of two fur colors their offspring will have.
monohybrid
Linkage groups are sets of genes transmitted
on the same chromosome.
In a genetic cross, what does the P generation represent?
parental generation
Mendel conducted his experiments of inheritance using ______ because they are easy to grow and cross, show distinguishable traits, and produce many offspring.
pea plants
The ______ rule states that the chance of two independent events occurring is equal to the product of the individual chances that each event will occur.
product
If a couple that are both heterozygous carriers of the cystic fibrosis allele have children, the chance that both their first and their second child are carriers is 0.5 x 0.5, or 25%, as determined by the
product rule
If the genotype for a trait is Tt, the t allele is called the ______ allele, whose effect is masked by the other allele.
recessive
The trait encoded by a ______ allele will only be exhibited if two copies of the allele are present in the genotype.
recessive
When they self-fertilize, true-breeding plants always produce offspring with a form of a trait that _____.
resembles the parent form of the trait.
Although Mendel did not know that homologous chromosomes separate during meiosis I such that the alleles of one gene are packaged into separate gametes, he developed the law of ______, which deduced this phenomenon.
segregation
Mendel deduced the law of _______, which states alleles of a gene move apart from each other during gamete formation.
segregation
One of the reasons that Mendel was able to discover the basic principles of genetics using pea plants is because pea plants
self-fertilize and cross-fertilize.
In the human genome, the X and Y chromosomes are called the
sex chromosomes
Select all of the following that are human gametes.
sperm; eggs
In a ______ cross, an individual with an unknown genotype is mated with an individual with a homozygous recessive genotype to determine the unknown genotype.
test
To determine if the genotype of a pea plant with a dominant phenotype is homozygous dominant or heterozygous, a _____ may be completed.
test cross
When Morgan crossed a male fruit fly that was heterozygous for two genes (AaBb) with a female fruit fly that was homozygous recessive for the same two genes (aabb), most of the offspring were either homozygous recessive or heterozygous for both genes, indicating that
the genes for these traits are linked.
The law of segregation deduced by Mendel states that
the two alleles of each gene segregate from each other during gamete formation.
If a gene exists in 10 different alleles in a population, how many alleles can be expressed in one diploid cell?
two
In a population of fruit flies, most flies have two antennae; based on this information, the phenotype of two antennae is definitely a _______ phenotype.
wild-type
The most common allele of a gene in a population of fruit flies is called the _____ allele.
wild-type
A gene is a
Stretch of DNA nucleotides that encodes a protein.
What describes the basis of gene linkage maps, as proposed by Sturtevant in 1911?
The farther apart two genes are, the more likely crossing over is to separate them.
Select the true statement about genes and chromosomes.
The number of genes in a cell exceeds the number of chromosomes.
Mendel mated a pea plant of true-breeding round, yellow seeds (RR YY) with a pea plant of true-breeding wrinkled, green seeds (rr yy). A Punnett square analysis shows that ______% of the F1 generation has round, yellow seeds.
100
In a cross between two traits, Mendel mated a pea plant of true-breeding round, yellow seeds (RR YY) with a pea plant if true-breeding wrinkled green seeds (rr yy). What is the genotypic ratio of the F1 generation?
100% Rr Yy
The first filial generation in a genetic cross is written as the ______ generation.
F1
The offspring of the first set of individuals mated in a particular cross is the
F1 generation
In humans, sex is determined by the sex chromosomes X and Y. If a human contains two X chromosomes, then its biological sex is ______; but if a human contains an X chromosome and a Y chromosome, then its biological sex is _______.
Female; male
An allele is a
Form of a gene.
Mendel's ________ states that the segregation of alleles for one gene does not influence the segregation of alleles for another gene during gamete formation.
Law of independent assortment
This diagram of gamete production from meiosis and gamete fusion in fertilization supports Mendel's.
Law of segregation.
The bottom panel of the picture shows the offspring genotypes that resulted from Morgan's cross between a male fruit fly heterozygous for two genes (AaBb) and a female fruit fly that was homozygous recessive for the same two genes (aabb). What accounts for the 5:1:1:5 genotypic ratio in the offspring that differs from the ratio Mendel would have predicted?
Linked genes
The physical location of a gene on a chromosome is called the gene's ______.
Locus or loci
After Mendel's work, biologists determined that a single chromosome carries
Many genes.
_______ discovered the principles of genetics before DNA, genes, and chromosomes were discovered.
Mendel
What is the first set of individuals mated in a particular cross?
P generation
After meiosis ||, what type of genetic material retains the allele combination present in the parents?
Parental chromatids
In a generic cross, what does the P generation represent?
Parental generation
An individual's _______ is its observable characteristics for a particular trait.
Phenotype
What are the observable characteristics of an individual's genes?
Phenotype
A ______ is a diagram that shows how the parental alleles may combine to form possible genotypes of the offspring.
Punnett square
What type of diagram is shown in the picture?
Punnett square
Select all of the following genotypes that are homozygous.
RR and rr
What type of trait in Mendel's studies could vanish in one generation and reappear in the next generation?
Recessive
Which of the following is a dihybrid cross?
RrYy x RrYy
Although Mendel did not know that homologous chromosomes separate during meiosis | such that the alleles of one gene are packaged into separate gametes, he developed the law of _______, which deduced this phenomenon.
Segregation
Genes that are located on the same chromosome and inherited together are called ______ genes.
linked
In the nucleus of eukaryotic cells, all of the DNA is divided into multiple ______, which are continuous, long strands of DNA wrapped around proteins.
chromosomes
Homologous chromosomes are
chromosomes that look alike and have the same sequence of genes but may not carry the same alleles.
Long strands of DNA and their associated proteins are called
chromosomes.
What process, depicted in the picture, produces nonidentical chromatids and can interrupt linkage between two genes?
crossing over
An example of a(n) _______ cross is mating of two rats that both have the genotype Ff Tt for fur color and tail length to examine which of two fur colors and tail lengths their offspring will have.
dihybrid
A cell with two complete sets of chromosomes is a ______ cell.
diploid
A human ______ cell has 46 chromosomes, 23 chromosomes from each parent.
diploid
A(n) _______ allele always exerts its effects when present.
dominant
What type of plant undergoes self-fertilization to produce some offspring that are identical to the parent and some that are different?
hybrid
Mendel deduced the law of ______ _______, which states that alleles for one gene are randomly separated into gametes in a way that is not influenced by the separation of alleles of another gene.
independent assortment
Select all of the following that are true about linked genes.
inherited together located on the same chromosome do not assort independently
What are collections of genes that are commonly inherited together?
linkage groups
Using the frequency of crossing between genes V and W, what can be created, as shown in the picture?
linkage map
