BIO EXAM 5
In pea plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short?
0%
Two genes are located the farthest from each other on a single chromosome, assuming no crossing over, recombination frequency for these genes is expected to be?
0%
Pea plant flower color may be purple or white. If purple is dominant, when a heterozygous plant is crossed with a heterozygous white flowering plant, what is the possibility that the offspring will be purple?
1/2
For a cross between a pea plant with the genotype PpYyRr and another with the genotype PpyyRr, the probability of the offspring having the genotype ppYyrr is
1/32
An organism with the genotype PpTtRrSs can have ________ different gametes.
16
Given 4 different characteristics assuming independent assortment, how many different types of gametes are possible?
16
Given four different characteristics, assuming independent assortment, how many different types of gametes are possible?
16
In horses, black is dependent of a dominant gene, B, and chestnut upon the recessive gene, b. The trotting trait is due to a dominant gene, T, the pacing gait to its recessive allele, t. If heterozygous black trotter (BbTt) is mated to a homozygous chestnut trotter (bbTT), how many of the F1 generation will be heterozygous black trotters (BbTt)?
25%
Suppose the brown allele for eye color (B) is completely dominant over the blue allele for eye color (b). If two brown-eyed parents produce a child that is blue-eyed, what is the probability that at least one out of the next two children they produce will also have blue eyes?
25%
The pedigrees above track duchenne muscular dystrophy (DMD) through several generations. DMD is an X linked recessive trait. Males are square symbols and females are circles. Affected individuals are filled symbols. If individuals I-1 and I-2 had another son, what is the chance that he would have DMD?
25%
The probability that two carriers of an autosomal (i.e. not an X or Y chromosome) recessive allele have offspring expressing the phenotype is
25%
DNA polymerase III requires which of the following to add a new nucleotide to a growing strand of DNA?
3' OH of a ribose sugar
Guanine makes up 15% of the nucleotides in a sample of DNA from a type of yeast. Approximately, what percentage of the nucleotides will be thymine?
35%
X-inactivation results in
Barr bodies
Which of the following covalently connects segments of the DNA sugar-phosphate backbone?
DNA ligase
Which of the following enzymes are associated with DNA replication
DNA ligase; topoisomerase; helicase
Humans have two unlinked genes, one for unattached or attached earlobes (E or e) and the other for the ability to curl the tongue (C or c). If someone's genotype is EeCc, which of the following is a possible gamete phenotype of that person?
EC
A person has A-type blood. One of the parents of this person has O-type. That person's genotype must be
IAI
For a monohybrid cross, self fertilization of the F1 fertilization produces offspring with a 1:2:1 phenotypic ratio for a particular trait. What does this suggest?
Incomplete dominance
Which of the following is true regarding non disjunction?
It may result in gametes with n+1 chromosomes; it may result in n-1 chromosomes
Why does the DNA double helix have a uniform diameter?
Purines pair with pyrimidines
Which of the following concepts is not attributable to Mendel
Sex Linked traits
Which of the following help keep apart the strands of DNA during replication?
Single stranded DNA binding protien
In some fruit flies, the mutant cinnabar (orange) eye color is inherited with another mutation, crooked legs. There never appears to be any recombination of these wild-type traits. This observation is best explained by which of the following?
The genes for cinnabar eye color and crooked leg shape are on the same chromosome and very close to each other.
The cross of two mice results in offspring with a 3:1 ratio for a particular trait. Assuming Mendelian genetics, what does this suggest?
The parents were heterozygous
Mendel's Law of segregation arises from
The separation of homologous chromosomes during anaphase I of meiosis.
Why are pea plants good model for studying genetics?
Traits are easily identified, short life cycle
A flowering plant obeys Mendelian genetics where the yellow flower is dominant over pink flowers. You are given a yellow flowering plant. What type of plant would you use to perform a test-cross with this plant to determine its genotype?
True breeding pink flowering plant
DNA polymerase III is responsible for
adding new DNA nucleotides to a 3' hydroxyl group
Cat fur color is located on x chromosome. Because of X inactivation a cat that is homozygous for orange fur color will have
an orange fur phenotype
Trisomy 21 is an example of
aneuploidy
In which of the following are there no gain or loss of DNA?
chromosomal inversion
recombination frequency for several mutant phenotypes located on the same chromosomes can be used to
create a genetic map
Recombination frequency for several mutant phenotypes located on the same chromosome can be used to
determine the size of the chromosomes
X-inactivation occurs during
development
Human somatic cells are
diploid
Which cell would be best to use for determining the karyotype of an individual?
dividing white blood cells
When one gene affects or controls the expression of another gene, this is generally referred to as
epistasis
Genetic variation can occur as a result of
fertilization, crossing over, independent assortment
Normal gametes produced by a homologous individual are always
haploid
A recessive trait will be observed in an individual who is
homozygous for that trait
The double strands of DNA are held together by
hydrogen bonding
The cross of two individuals results in offspring with a 1:2:1 phenotypic ratio for a particular trait. What does this suggest?
incomplete dominance
To perform gel electrophoresis, a sample of DNA is placed between two electrodes. DNA is attracted to the positively charged electrode. This is because DNA
is rich in phosphate groups
Okasaki fragments are found in the ______________ during DNA replication
lagging strand
The fact that all characteristics Mendel studied exhibited independent assortment implies that each of these alleles were?
located on different chromosomes
Hemophilia is recessive, sex linked disorder where the person's blood does not clot properly. Males are more likely affected by this disorder than females because
males are hemizygous for the X chromosome
Independent assortment occurs during
meiosis
Crossing over is more likely between two genes that are
more distant from each other on the same chromosome
You have a set of plants that are true breeding for green seeds. After 20 generations, you find offspring that have yellow seeds. This occurred because of a
mutation
If a reciprocal translocation occurs between homologous pairs of chromosomes
no effect is observed because it only produces an effect between non-homologous chromosomes
Down's Syndrome (Trisomy 21) is typically the result of
non-disjunction
In the Hershey-Chase experiments, viral nucleic acids were followed using radioactive phosphorous, while viral proteins were monitored with radioactive sulfur. This was done because
nucleotides contain phosphate groups and protein shape is manipulated by disulfide bridges
The sugar phosphate backbones of DNA run anti-parallel. This refers to the fact that
one strands runs 3' to 5', while the other 5' to 3'
The observable trait of an organism is called its
phenotype
A chromosomal inversion is most likely to affect
phenotype due to changes in gene regulation
When one gene has multiple phenotypic effects we call this?
pleiotropy
A karyotype can be used to most readily identify
polyploidy and aneuploidy
DNA polymerase I is responsible for
removing the primer and replacing it with DNA nucleotides
Hereditary information is stored by DNA within its
sequence of nitrogenous base pairs
Okasaki fragments are composed of
short DNA sequences
Mendel's Law of Independent Assortment relates to
the arrangement to homologous pairs of chromosomes during metaphase I of meiosis
A chromosomal deletion is most likely to affect
the likelihood of male or female offspring; gene expression
Recombination frequency is a function of
the physical distance between two alleles on the same chromosomes
True breeding blue flowering plants always have progeny that are
the same phenotype as the parents. the same genotype as the parents
Snapdragons exhibit incomplete dominance; crossing a red true breeding plant with a white true breeding plant yields a pink F1 generation. Self-pollination of the F1 generation yields F2 offspring with
the same phenotypic and genotypic ratios; a 3:1 phenotypic ratio and a 1:2:1 genotypic ratio
White flowering plants were not observed in the F1 generation following a cross of true-breeding purple and white flowering plants in Mendel's monohybrid cross experiment because
the white allele is recessive
If two genes are linked, _____.
they are on the same chromosome
Dideoxynucleosides are used in DNA sequencing to randomly stop DNA elongation. This is because
they lack a 3' hydroxyl group