Biology- The Living World Ch.9
Match the sexual life cycle with the correct organism. 1.) animal 2.) protist 3.) plant
1.) almost all are diploid for the multicellular stage of their life cycle 2.) haploid most of their lives 3.) spend nearly equal portions of its life cycle as haploid and diploid individuals
If a parent cell contained six chromosomes, how many chromosomes would be present in a haploid gamete produced by the cell?
3
The eggs (gametes) produced by an adult human female each contain 23 chromosomes. The number of chromosomes contained in the female's diploid somatic cells would be _______.
46
If an organism has three homologous pairs of chromosomes, how many different orientations of chromosomes on the metaphase plate are possible?
8
Humans have 23 pairs of homologues chromosomes, with each gamete receiving one homologue this results in a potential for more than ______ different types of gametes.
8 million
_______ fission of prokaryotes is an example of asexual reproduction.
Binary
The _______ exchange that occurs when the arms of non-sister chromatids cross over adds more recombination.
DNA, genetic, or deoxyribonucleic acid
The stage of meiosis II shown here is ______
During meiosis I, synapsis is ______.
How does a gamete differ from a zygote?
Gametes contain only half of the complement of chromosomes.
What meiotic division is most similar to mitosis?
II
_______ _______is a process that results in the formation of gametes that have different combinations of parental chromosomes. This is partially due to random alignment of chromosomes along the metaphase plate during metaphase I.
Independent assortment
What is the significance of meiosis?
Meiosis reduces the number of chromosomes to ensure a consistent number from one generation to the next.
Select the statement below that is true of haploid cells.
Reproductive cells that contain only one set of chromosomes.
How do you distinguish sexual reproduction from asexual reproduction?
Sexual reproduction involves the fusion of gametes from two parents.
Select the statement below that is true of diploid cells.
Somatic cells that contain two sets of chromosomes.
What describes reduction division of meiosis?
The chromosome homologues do not replicate between the two nuclear divisions.
During meiotic division, chromosome number is reduced in gametes. Why is this important?
This ensures that the zygote has the correct number of chromosomes.
Somatic cells are ______.
diploid body cells found in animals
A cell taken from animal heart tissue would be ______, whereas an egg cell would be ______.
diploid; haploid
Somatic cells are _______ because they have two sets of chromosomes, however gametes are _______ because they only have one set of chromosomes.
diploid; haploid
The fusion of gametes to form a new cell is called _______ , or syngamy.
fertilization
The process occurring at the tip of the black arrow is called
fertilization
When two gametes fuse and form a zygote, this process is called ______.
fertilization
The final result of meiosis II is
four haploid cells.
The term _____ refers to the egg or sperm cells of an organism.
gamete
What is the term that refers to the egg or sperm of an organism?
gamete
At the end of telophase I, the cells are ______.
haploid
Exchanging DNA during crossing over
increases the possible genetic combinations that can occur among gametes.
The random orientation of chromosomes on the metaphase plate that results in gametes with different combinations of parental chromosomes is called ______.
independent assortment
Which of the following occur only during meiosis I?
independent assortment crossing over homologous pairs separate
Three mechanisms that make key contributions to generate new genetic combinations are
independent assortment, crossing over, and random fertilization.
In meiosis the replication of chromosomes occurs during ______.
interphase
A zygote ______.
is a diploid cell formed by the fusion of an egg and sperm cell
A type of cell division called _______ reduces chromosome number, producing four haploid gametes; it ensures a consistent chromosome number from one generation to the next when gametes combine in fertilization.
meiosis
Meiosis has two rounds of cell division called ______.
meiosis I and meiosis II
Select the two main divisions of meiosis.
meiosis II meiosis I
During what meiotic II phase do spindle fibers bind to both sides of the centromeres and the chromosomes line up along a central plane?
metaphase II
In what stage of meiosis does crossing over occur?
prophase I
What process in meiosis is responsible for the production of daughter cells with half as many chromosomes as the parent cell?
reduction division
Select the two unique features that distinguish meiosis from mitosis.
reduction division synapsis
What occurs during interphase that precedes meiosis?
replication of chromosomes
The main outcome of the four stages of meiosis II is to
separate the sister chromatids.
Reproduction that involves alternating meiosis and fertilization is called _____ reproduction.
sexual
In animals, the diploid cells of the body are called _____ cells, while the diploid, gamete-forming cells are referred to as _____ cells.
somatic; germ-line
What is the process called when homologous chromosomes pair all along their lengths?
synapsis
What process brings homologous chromosomes close enough together to permit crossing over?
synapsis
What are the two unique features that distinguish meiosis from mitosis?
synapsis and reduction division
Select the four stages of meiosis I.
telophase I anaphase I metaphase I prophase I
The fusion of gametes during fertilization produces a single, diploid cell called a
zygote
Match the stage on the left with the correct description on the right. 1.) metaphase of mitosis 2.) metaphase I 3.) metaphase II
1.) chromosomes line up individually at the cell's central plane 2.) homologous chromosome pairs line up at the cell's central plane 3.) haploid number of chromosomes lined up at the cell's central plane
Match each meiosis II phase with its correct description. 1.) Prophase II 2.) Metaphase II 3.) Anaphase II 4.) Telophase II
1.) chromosomes recondense and a new spindle is formed 2.) chromosomes line up along a central plane 3.) sister chromatids move to opposite poles 4.) the nuclear envelope reforms around four sets of daughter chromosomes
Match each term that applies to sexual reproduction with its correct description. 1.) Gametes<----> 2.) zygote<----> 3.) Fertilization<---->
1.) egg and sperm 2.) the product of fusion of an egg and sperm 3.) fusion of gametes to form a new cell
Match the term on the left to the correct definition on the right. 1.) synapsis 2.) crossing over
1.) homologous chromosomes align along their lengths and are held together by cohesin 2.) homologous chromosomes exchange parts of their chromatids
Match the round of meiotic cell division on the left with the correct description on the right. 1.) meiosis I <----> 2.) meiosis II <---->
1.) homologous chromosomes separate 2.) sister chromatids separate
Match the stage on the left with its correct description on the right. 1.) anaphase of mitosis 2.) anaphase I 3.) anaphase II
1.) identical sister chromatids are separated 2.) homologous pairs are separated 3.) sister chromatids that may no longer be identical due to crossing over are separated
Match the term with the correct description. 1.) Haploid <----> 2.) Diploid<----> 3.) Sexual<----> 4.) Asexual<---->
1.) one set of chromosomes present 2.) two sets of chromosomes present 3.) reproduction that involves the alternation of meiosis and fertilization 4.) reproduction by mitotic division
Place the phases of meiosis in the correct order starting with the first phase at the top.
1.) prophase I 2.) metaphase I 3.) anaphase I 4.) telophase I
Match the meiotic I phase with the correct description. 1.) Prophase I 2.) Metaphase I 3.) Anaphase I 4.) Telophase I
1.) the two versions of each chromosome pair up and exchange segments 2.) homologous pairs of chromosomes align along the spindle equator 3.) homologues with their two sister chromatids still attached move to opposite poles 4.) individual chromosomes gather together at the two poles
A somatic cell of an adult male has 46 chromosomes. The number of chromosomes in his sperm cells would be _______.
23
If a sperm cell containing 12 chromosomes from the male parent fused with an egg from the female parent, how many total chromosomes would be present in a diploid zygote?
24
When meiosis is complete, how many haploid cells are produced?
4
Select all of the true statements distinguishing somatic and germ-line cells.
Both somatic and germ-line cell are diploid. Somatic cells make up most of the organism and germ-line cells give rise to gametes.
Select the true statements about meiosis.
During prophase II, there is no crossing over. Microtubules can only attach to one side of each homologous chromosome during meiosis I.
True or false: At some point in a somatic cell's life cycle, it will be temporarily haploid.
False
Which of the following best describes meiosis II?
Follows similar pattern as mitosis, without chromosomes replicating beforehand and sister chromatid separating during anaphase II.
Which of the following statements correctly describes the cellular process of meiosis?
Germ cells undergo two divisions resulting in four genetically distinct haploid cells.
_______ _______ is a process that results in the formation of gametes that have different combinations of parental chromosomes. This is partially due to random alignment of chromosomes along the metaphase plate during metaphase I.
Independent assortment
How do somatic cells differ from germ-line cells?
Somatic cells undergo mitosis to produce identical diploid cells and germ-line cells undergo meiosis to produce haploid gametes.
During anaphase of meiosis I _______ chromosomes separate, whereas during anaphase of meiosis II _______ chromatids are separated.
homologous; sister
True or false: The life cycles of all sexually reproducing organisms alternate between cells with diploid chromosome numbers and cells with haploid chromosome numbers.
True
Prokaryotes reproduce asexually through a process called
binary fission.
Select all of the following that describe somatic cells in animals.
body cells found in non-reproductive organs diploid
In a process called _______ _______, chromosomes break in the same place on non-sister chromatids and sections of chromosomes are swapped between the homologous chromosomes.
crossing over
What process occurs in prophase I and ties the two chromosomes of a homologous pair together?
crossing over
Select all the mechanisms that occur during sexual reproduction that make key contributions to generating diversity.
crossing over independent assortment random fertilization
Two sets of chromosomes are present in somatic cells of adult individuals, making them _______ (2n) cells.
diploid
Select all of the following that are true about diploid cells.
diploid cells contain two sets of chromosomes somatic cells are diploid
Select all of the following that are true about haploid cells.
gametes are haploid haploid cells contain only one set of chromosomes
From his observations, Pierre-Joseph van Beneden discovered that cells called _______ (eggs and sperm) each contained half the complement of chromosomes. When these cells fuse they produced a cell called a _______ , which contains the full complement of chromosomes.
gametes; zygote
Diploid, gamete-forming cells located in reproductive organs are referred to as _______-line cells.
germ
What type of cell is found in reproductive organs and undergoes meiosis to form gametes?
germ-line
If only one set of chromosomes is present in the cell, the cell is called a _______(1n) cell.
haploid
In what type of cell is only one set of chromosomes present?
haploid
A sperm cell from an animal would be ______, whereas its skin cell would be ______.
haploid; diploid
How does meiosis I differ from meiosis II? Select all that apply.
in meiosis I, homologous chromosomes separate in meiosis II, sister chromatids separate
What is a key evolutionary consequence of sexual reproduction?
increases genetic diversity
The process of ______ reduces chromosome number by half and results in four daughter cells.
meiosis
The type of cell division that occurs at the tips of the black arrows is called
meiosis
With 23 pairs of chromosomes humans have over 8 ______ potential different kinds of gametes that can be produced.
million
Select all the characteristics of sexual reproduction.
promotes new traits in a changing environment generates genetic diversity
In which phase of meiosis I do the two versions of each chromosome pair up and exchange segments?
prophase I
Meiosis I is traditionally divided into four stages. These stages are
prophase I, metaphase I, anaphase I, and telophase I.
Independent assortment is a process where the ______.
random orientation of homologues results in gametes with different combinations of parental chromosomes
The alternation between diploid chromosome numbers and haploid chromosome numbers (alternation of generations) is the key characteristic of the ______.
sexual life cycle
What term describes the non-gametic cells of a sexually-reproducing organism?
somatic
During meiosis I, synapsis is ______.
the pairing of homologous chromosomes all along their length
What is one role of of crossing over in meiosis I?
tie chromosomes together so that microtubules can only attach to one side of each homologue
Random fertilization further increase genetic diversity. Fusing a unique sperm with a unique egg from the same two individuals, the potential number of genetically unique zygotes created is 70 ______.
trillion
In ______, sexual reproduction is the predominant mode of reproduction, and allows for genetic recombination and versatility.
vertebrates
The fusion of gametes during fertilization produces a single, diploid cell called a _______.
zygote
When an egg and sperm fuse, the resulting single cell is called a(n) ______.
zygote