Chapter 3 & 4 - Inheritance, Sex, and Chromosomes
A normal human somatic cell carries ______ pairs of chromosomes for a total of ______.
23 ; 46
In most animals, a cell will contain the following number of chromosomes after mitosis:
2n
Meiosis I reduces the chromosomes from what ploidy?
2n to n
In his classical experiments with white-eyed fruit flies, Morgan obtained red-eyed F1 individuals by crossing white-eyed males with red-eyed (wild-type) females. When he crossed F1 males and females, he obtained an F2 generation with an overall ratio of _____.
3 (red-eyed individuals):1 (white-eyed individuals)
Insert a number into the blank: Most human somatic cells contain a total of ____ chromosomes.
46
What is chromatin?
A complex between DNA and proteins that is found in eukaryotic cells
A key difference between daughter cells resulting from mitosis and meiosis is that:
After meiosis, cells are haploid. After mitosis, cells are diploid.
When you consider only the sex chromosomes, what types of gametes are produced by a female individual of a species with the XY system of sex determination?
All gametes carry a X chromosome.
One form of hereditary deafness is inherited with an X-linked recessive allele. What can be expected for the offspring of a deaf mother and a father with normal hearing?
All of the sons will be deaf and all of the daughters will have normal hearing. Reason: Sons will express the deafness allele inherited from their mother since the the Y chromosome from their father does not have carry any alleles to mask it.
This diagram represents a cell that has an original diploid number (2n) of four chromosomes. The cell is shown in which phase of cell division?
Anaphase II of meiosis
Define autosomes.
Any chromosome that is not a sex chromosome
Name 2 aspects of meiosis that contribute to genetic diversity in a population.
Crossing-over Independent assortment
What chromosomes determine a female, male?
Female: XX Male: XY
During which part of interphase do cells achieve the majority of their growth?
G1
Hemophilia is inherited with an X-linked recessive allele. Which term describes the genotype for a male who has this blood-clotting disorder?
Hemizygous
Name 2 events of telophase I of meiosis.
Homologs have reached their respective poles. The nuclear membrane reforms in many species.
In which of the following does DNA replication NOT occur: A. Interphase of mitosis B. Interphase 1 of meiosis C. Interphase 2 of meiosis D. None of the above
Interphase 2 of meiosis
Humans who have two X chromosomes and a Y chromosome (XXY) are said to have ____ syndrome.
Klinefelter
The chromosomes line up across the middle of the cell during:
Metaphase
During which of the following phases are tetrads organized along a plate in the center of the cell?
Metaphase of meiosis I
The kind of nuclear division followed by cell division that results in two daughter cells containing the same number and type of chromosomes as the original parent cell is called ___.
Mitosis
What results in two daughter cells containing the same number and type of chromosomes as the original parent cell
Mitosis
During what stage of meiosis II does the nuclear envelope break down?
Prophase II
Humans carrying an X and no second sex chromosome (XO) are said to have ________ syndrome
Tendler?
Name 3 events that occur during prophase of mitosis.
The chromatin condenses into more compact structures. The centrosomes move apart. The nucleolus becomes less visible.
Name 2 the events that occur during pro-metaphase.
The nuclear envelope completely breaks down. Chromosomes attach to the microtubules through the kinetochore.
What makes the chromosomes come together for crossing over?
The synaptonemal complex
Mitosis produces two diploid daughter cells, while meiosis produces four haploid daughter cells. T/F
True
_______ genes are those that are physically located on the X chromosome.
X-linked
What is the inheritance pattern for a trait that is more likely to occur in females and which is seen in every generation?
X-linked dominant
What is the inheritance pattern for a trait that generally affects more males than females and will never pass from father to son?
X-linked recessive
What is the inheritance pattern for a trait that more commonly affects males than females and can often be observed in brothers or fathers of a woman who has affected sons?
X-linked recessive
In his large-scale crosses between red-eyed males and white-eyed females, Bridges observed a small proportion (about 1 in 2000) of white eyed female offspring which he determined to be XXY individuals. How did these individuals obtain their sex chromosomes? Multiple choice question.
XX from their mother, Y from their father
The male is ___ and the female is ___.
XY, XX
Which of the the following genotypes corresponds to a white-eyed male fruit fly?
X^wY
A fruit fly with the genotype XwXw is ____.
a white-eyed female
In his classical experiment with white-eyed Drosophila flies, Thomas Hunt Morgan crossed red-eyed (wild-type) females with white-eyed males. He then crossed the red-eyed F1 generation fruit flies with each other and discovered that, while the F2 generation included both red-eyed and white-eyed individuals, ____.
all white-eyed individuals were male
Define crisscross inheritance.
an inheritance pattern in which males inherit the character of a trait from their mothers, while daughters inherit the character from their fathers.
The two pairs of sister chromatids separate and move to opposite poles best describes what phase of cell replication?
anaphase I of meiosis
What describes cells or organisms whose chromosome sets are not all complete?
aneuploids
In humans, if a non-disjunction event leads to an individual that is XXY, they would:
be male because they have a Y chromosome
During the G1 part of interphase, ______.
cells grow in size
Define Germ cells
cells that produce gametes, or 'sex cells'.
What ensures that cell cycle events occur in the proper sequence?
checkpoints
Chromosomes usually exist in the nucleus as what?
chromatin
What is the name for the diffuse complex of DNA and proteins in a eukaryotic cell?
chromatin
The anaphase stage of meiosis I is characterized by the separation of the two _______ of a tetrad from each other and their migration to opposite poles of the cell.
chromosomes
The structures within all living cells that contain the genetic material are called ___.
chromosomes
The structures within living cells that contain the genetic material are best defined as what?
chromosomes
During prophase of mitosis, chromosomes ______ into discrete structures. Furthermore, the two _______ separate moving towards the poles and the mitotic _______ begins to form.
condense, centrosome, spindle
The interchange of corresponding chromatid segments of homologous chromosomes during prophase I of meiosis is called ______.
crossing over
Define hemizygous
describes the genotype for genes present in only one copy in an otherwise diploid organism, such as X-linked genes in a male.
In a ______ cell, each type of chromosome is a member of a pair.
diploid
Humans with Turner syndrome are _____.
female (anuploid)
Cells that are destined to undergo meiosis and produce gametes are called _____ cells.
germ(line)
Meiosis produces cells that contain _____.
half the number of chromosomes found in other cells within the same organism
Hemophilia is an X-linked recessive trait. One of the conditions that must be met for a female child to have hemophilia is that ______.
her father must have hemophilia
One form of hereditary deafness is inherited with an X-linked recessive allele. A woman with normal hearing has a son with hereditary deafness. The woman's genotype at this gene locus is ______.
heterozygous
Synapsis is the process by which _____.
homologous chromosomes recognize each other and begin to align themselves in prophase I
Meiosis increases genetic diversity in a population through crossing-over and by _____ assortment of parental chromosomes.
independent
In eukaryotes, ______ is the type of cell division that is responsible for the production of gametes.
meiosis
In ______ of meiosis, the bivalents (which are also termed tetrads) are aligned along the center of the cell.
metaphase I
Bridges observed that in a cross between white-eyed females and red-eyed males, the majority of the progeny were red-eyed females and white-eyed males. However, a very small number of males had red eyes, and females had white eyes. Bridges proposed this was due to _______ in meiosis.
nondisjunction
Trisomies occur due to _____.
nondisjunction
In meiosis, crossing-over refers to the physical exchange of pieces between _____.
nonsister chromatids of homologous chromosomes
The of a eukaryote is the organelle that contains most of the genetic material found in the cell.
nucleus
What organelle found in eukaryotic cells that contains the hereditary material?
nucleus
During ______, pairs of sister chromatids become attached to kinetochore microtubules which emanate from opposite poles of the cell.
pro-metaphase
If the chromosomes decondense during the preceding interphase, they recondense during _____ II of meiosis.
prophase
The two halves of a chromosome after DNA has been replicated are the:
sister chromatids
A cell _____ is any cell of the body that is not a gamete or precursor to a gamete.
somatic
In G0, what cells are actively going through mitosis?
somatic cells
During prophase of meiosis I, homologous chromosomes recognize and begin to align with each other via a process called ____.
synapsis
During the zygotene stage of meiosis I, the _______ complex aligns homologous chromosomes.
synaptonomal
During ______ of meiosis, the pairs of sister chromatids have reached the opposite poles of the cell, where in most cases, nuclear membranes begin to form around them.
telophase I
A bivalent is also called a ____, because it is composed of four chromatids.
tetrad
A trait that a son can inherit only from his mother must be due to an allele found on ______.
the X chromosome
A bivalent, or tetrad, consists of _____
two pairs of sister chromatids of homologs
A diploid cell is defined as a cell that has ______.
two sets of chromosomes
Color blindness is due to an X-linked recessive allele. To be color blind, females must inherit ______ copy(ies) of this allele and males must inherit ______ copy(ies).
two; one
