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BIOL M01 Exam 2

Terms in this set (70)

Only ______ is NOT a stage of mitosis.
interphase
Reproduction in prokaryotes occurs primarily through the process known as
fission
A somatic cell with two of each type of chromosome characteristic of the species has a (n) _____ chromosome number.
diploid
The genetic material (DNA) of eukaryotes is organized into
chromosomes
In a chromosome, a ________ is a constricted region with attachment sites for microtubules.
centromere
The product of DNA synthesis, also known as nucleoprotein duplication, is
two chromatids
During prophase, duplicate chromosomes
consist of nucleoproteins, contain centromeres, consist of chromatids
A duplicated chromosome has _____ chromatid(s).
two
After mitosis, the chromosome number of a daughter cell is _______ the parent cell's.
the same as
During the S period of interphase
synthesis (or replication) of the DNA takes place
Chromosomes separate during
anaphase
Centrioles and a starburst cluster of spindle fibers would be found in
only animal cells
Mitosis and cytoplasmic division function in _______.
asexual reproduction of single-celled eukaryotes; growth, tissue repair, and sometimes asexual reproduction in many multicelled eukaryotes
The term "2n" means that
the diploid chromosome number is present, within a single nucleus chromosomes exist in homologous pairs
In higher animals, meiosis results in the production of
egg cells (ova), gametes, sperm cells
Recombination of alleles on non-sister chromatids occurs during
crossing over
If both homologous chromosomes of each pair exist in the same nucleus, that nucleus is
diploid
A daughter chromosome
is formed during anaphase II, is the same as a homologous chromosome, is the result of separation of chromatids
Gametogenesis in female animals results in
one gamete and three polar bodies
Generally, a pair of homologous chromosomes ______.
carry the same genes; are the same length, shape; interact at meiosis
Each chromosome moves away from its homologue and ends up at the opposite spindle pole during _____.
anaphase I
Sister chromatids of each chromosome move apart and end up at opposite spindle poles during _______.
anaphase II
Sexual reproduction requires _____.
meiosis, gamete formation, fertilization
Meiosis is a division mechanism that produces ______.
four nuclei
Meiosis _____ the parental chromosome number.
halves
In a monohybrid cross
the parents are always heterozygous
The genetic makeup of an organism is its
genotype
The sex chromosome determining maleness is
the Y chromosome
A nucleus containing only one of the two homologues is
haploid
An example of a trait controlled by multiple alleles is
ABO blood typing in humans
One of Mendel's principles is the Principle of
Segregation
What is the expected genotypic ratio resulting from a heterozygous X heterozygous monohybrid cross?
1:2:1
What is the expected phenotypic ratio resulting from a homozygous recessive X heterozygous cross?
1:1
F1 offspring of the monohybrid cross AA x aa are
all purple
Second-generation offspring from a cross are the
F2 generation
Assuming complete dominance will occur, the offspring of the cross Aa x Aa will show a phenotypic ratio of
3:1
An organism that is phenotypically dominant is crossed with a true-breeding recessive organism. Some of the offspring are recessive in appearance. What is the genotype of the dominant parent?
Rr
In pea plants, smooth seeds (S) are dominant over wrinkled seeds (s) , and purple flowers dominant over white flowers. A cross is made between two individuals that are heterozygous for each of these traits. What is the probability of getting a white-flowered wrinkled seed offspring?
1/16
The Y chromosome is in ____.
Sperm
Crosses between F1 individuals resulting from the P1 cross AABB x aabb lead to F2 phenotypic ratios close to
9:3:3:1
Mendel's First Law states that:
a gamete has an equal probability of possessing either member of an allele pair; alleles segregate at the time of gamete formation
If a true-breeding purple-flowered pea plant (purple is dominant to white) is crossed with a true breeding, white-flowered pea plant, which of the following describes the F1 generation?
all purple
If the F1 plants in the classic monohybrid cross (purple/white flowers) were crossed with each other, what would be the phenotypic ratio of the F2 generation plants?
3:1
What species did Mendel use for his experiments?
Pea plants
The best statement of Mendel's principle of independent assortment is that ________.
the two hereditary units that influence a certain trait separate during gamete formation
All the different molecular forms of the same gene are called ________.
Alleles
If two heterozygous individuals are crossed in a monohybrid cross involving complete dominance, the expected genotypic ratio is ________.
1:2:1
In the F2 generation of a cross between a red-flowered snapdragon (homozygous) and a white-flowered snapdragon, the expected phenotypic ratio of the offspring is ________.
1/4 red, 1/2 pink, 1/4 white
In a testcross, F1 hybrids are crossed to an individual known to be ________ for the trait.
Homozygous recessive
The tendency for dogs to bark while trailing is determined by a dominant gene, S, whereas silent trailing is due to the recessive gene, s. In addition, erect ears, D, is dominant over drooping ears, d. What combination of offspring would be expected from a cross between two erect-eared barkers who are heterozygous for both genes?
9/16 erect barkers, 3/16 drooping barkers, 3/16 erect silent, 1/16 drooping silent
If a mother has type O blood, which of the following blood types could NOT be present in her children?
Type AB
A single gene that affects several seemingly unrelated aspects of an individual's phenotype is said to be ________.
pleiotropic
Suppose two individuals, each heterozygous for the same characteristic, are crossed. The characteristic involves incomplete dominance. The expected phenotype ratio of their progeny is ________.
1:2:1
The mutation that results when a piece of a chromosome breaks off and is lost is called
a deletion
Asbestos, radiation, and ultraviolet light are all examples of _____.
mutagens
A family record that indicates the occurrence of a trait is
pedigree
Trisomy is a mutation that results in a cell having an extra
chromosome
An individual with which blood type can receive blood from any donor?
Type AB
An individual with which blood type can blood donate to any donor?
Type O
The probability of a crossover occurring between two genes on the same chromosome is
increased if they are farther apart on the chromosome
All the genes located on a given chromosome compose a ________.
linkage group
Chromosomes other than those involved in sex determination are known as ________.
autosomes
The farther apart two genes are on a chromosome, ________.
the greater will be the frequency of crossing over and recombination between them
Karyotype analysis is ________.
the greater will be the frequency of crossing over and recombination between them
Karyotype analysis is ________.
used in prenatal diagnosis to detect chromosomal mutations and metabolic disorders in embryos
Red-green color blindness is a sex-linked recessive trait in humans. A color-blind woman and a man with normal vision have a son. What are the chances that the son is color-blind? If the parents ever have a daughter, what is the chance that a daughter will be color-blind? (Consider only the female offspring.)
100%, 0%
Suppose that a hemophilic male (X-linked recessive allele) and a female carrier for the hemophilic trait have a nonhemophilic daughter with Turner syndrome. Nondisjunction could have occurred in ________.
father only
Nondisjunction involving the X chromosome occurs during oogenesis and produces two kinds of eggs, XX and O (no X chromosome). If normal Y sperm fertilize the two types, which genotypes are possible?
XXY and YO
Of all phenotypically normal males in prison, the type once thought to be genetically predisposed to becoming criminals was the group with ________.
XYY disorder
Amniocentesis is _____.
used in prenatal diagnosis; a small sample of amniotic fluid is drawn to detect chromosomal mutations and metabolic disorders in embryos
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