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