Chapter 13: Meiosis and the Sexual Life Styles
Regarding the role of cohesin protein in maintaining cohesion between sister chromatids, which of the following statements is false? - During meiosis I, cohesion holds sister chromatids together along their lengths as chiasmata form between homologs. - Cleavage of cohesins between sister chromatid arms at anaphase I allows homologs to separate. - During meiosis II, cohesion holds sister chromatids together along their lengths as the second meiotic spindle forms. - During meiosis I, cohesion holds sister chromatids together along their lengths as chiasmata form between homologs and cleavage of cohesins between sister chromatid arms at anaphase I allows homologs to separate. - During meiosis I, cohesion holds sister chromatids together along their lengths as chiasmata form between homologs and during meiosis II, cohesion holds sister chromatids together along their lengths as the second meiotic spindle forms None of the listed responses is false.
- During meiosis II, cohesion holds sister chromatids together along their lengths as the second meiotic spindle forms.
Ignoring crossover, how many kinds of gametes can be produced by an organism with a diploid number of 8? 16 2 8 4 32
16
A life cycle in which the only multicellular form is haploid is most typical of __________. fungi plants protists fish primates
fungi
Allelic variation is an important source of __________ in a population. clonal diversity None of the listed responses is correct. asexual reproduction genetic diversity mitosis
genetic diversity
A pair of genetic structures carrying genes that control the same inherited characters are called __________. zygotes autosomes clones sister chromatids nonsister chromatids homologous chromosomes
homologous chromosomes
Somatic cells in humans contain __________ set(s) of chromosomes and are therefore termed __________. one; haploid two; diploid three; triploid one; diploid two; haploid
two; diploid
__________ are a group of genetically identical individuals produced by a process called __________. Clones; asexual reproduction Homologs; meiosis Clones; sexual reproduction Gametes; asexual reproduction Gametes; meiosis
Clones; asexual reproduction
Which life cycle stage is found in plants but not animals? Unicellular diploid Multicellular haploid Zygote Multicellular diploid Gamete
Multicellular haploid
A clone is the product of __________. asexual reproduction meiosis sexual reproduction and meiosis sexual reproduction asexual reproduction and mitosis mitosis
asexual reproduction and mitosis
he zipper-like complex that forms in meiosis occurs during __________ and is called the __________. prophase I; synaptonemal complex prophase I; centromeric complex prophase II; meiotic complex metaphase I; synaptonemal complex metaphase II; meiotic complex
prophase I; synaptonemal complex
How many genes are present in the human genome? Hundreds Tens of thousands 23 46 A virtually infinite number
tens of thousands
Which of the following occurs in meiosis, but not mitosis? - The cells formed have the same combination of genes as found in the initial cell. - Sister chromatids undergo disjunction. - The nuclear envelope disappears. - A spindle apparatus forms. - Homologous chromosomes separate.
- Homologous chromosomes separate.
Unless the chromosomes were stained to show band patterns, a karyotype would be least likely to show which of the following? - The attachment of a large part of a chromosome to another chromosome. - Part of a chromosome turned around. - A large part of a chromosome duplicated. - A missing chromosome. - An extra chromosome.
- Part of a chromosome turned around.
What is a locus? - The precise location of a gene on a chromosome. - A structure that appears during prophase I and consists of two paired genes. - A type of spore made only by fungi. - A cell with two chromosome sets.
- The precise location of a gene on a chromosome.
Which of the following statements about homologous chromosomes is correct? - They are found in the cells of human females but not in human males. - They are found in haploid cells. - They pair up in prophase II. - They have genes for the same traits at the same loci. - They are found in animal cells but not in plant cells.
- They have genes for the same traits at the same loci.
The life cycle called __________ in plants has two multicellular stages: the __________ and the __________. - germ cell production; haploid gametophyte; diploid sporophyte - reduction division; diploid gametophyte; haploid sporophyte - reduction division; haploid gametophyte; diploid sporophyte - alternation of generations; diploid gametophyte; haploid sporophyte - alternation of generations; haploid gametophyte; diploid sporophyte
- alternation of generations; haploid gametophyte; diploid sporophyte
Sister chromatids differ from nonsister chromatids in that sister chromatids __________. - are part of only the maternal set - always come from nonsister chromatids - are never found in the paternal set - are part of nonhomologous chromosomal sets - are products of the S phase of the cell cycle and are two copies of one chromosome
- are products of the S phase of the cell cycle and are two copies of one chromosome
Somatic cells in humans differs from gametes in that human somatic cells __________. - are important in sexual reproduction - are always haploid - do not contain sex chromosomes - replicate by a process called meiosis - contain two sets of each of the 23 chromosome types
- contain two sets of each of the 23 chromosome types
Regardless of whether an organism is an animal, a plant, a fungus, or an algal cell, all zygotes are __________ and are formed during the __________ of two __________ gametes. - diploid; fertilization; haploid - haploid; fertilization; diploid - clones; meiotic division; diploid - None of the listed responses is correct because only animals have zygotes. - clones; mitotic division; diploid
- diploid; fertilization; haploid
Darwin realized the importance of heritable variation to evolution __________. - even though he never read any of Gregor Mendel's work - and incorporated Gregor Mendel's work into his writings without giving Mendel credit for his ideas - None of the listed responses is correct. - by studying Gregor Mendel's work - and incorporated Gregor Mendel's work into his writings
- even though he never read any of Gregor Mendel's work
Characteristic of the bdelloid rotifer is that it __________. - is fungus-like and therefore haploid - produces diploid gametes - has never experienced genetic diversity - is an example of an animal that has not reproduced sexually in 40 million years - is more plantlike and therefore undergoes alternation of generation
- is an example of an animal that has not reproduced sexually in 40 million years
The major contribution of sex to evolution is that __________. - it provides a method to increase genetic variation - it is the only mechanism for species to reproduce - it provides a method to increase genetic variation and it is the only mechanism for species to reproduce - it provides a way in which somatic mutations can be inherited - it is the only mechanism for species to reproduce and it provides a way in which somatic mutations can be inherited
- it provides a method to increase genetic variation
The process called __________ reduces the chromosome number by __________. - meiosis; dividing without chromosome duplication - mitosis; destroying one set of information prior to division - mitosis; dividing without chromosome duplication - mitosis; two consecutive cell divisions - meiosis; two consecutive cell divisions
- meiosis; two consecutive cell divisions
Genetic diversity requires __________. - sexual reproduction, independent assortment, crossing over between nonsister chromatids of homologous chromosomes, and random fertilization - sexual reproduction, nonindependent assortment, crossing over between nonsister chromatids of homologous chromosomes, and random fertilization - sexual reproduction, independent assortment, crossing over between sister chromatids of homologous chromosomes, and nonrandom fertilization - asexual reproduction, independent assortment, crossing over between sister chromatids of homologous chromosomes, and random fertilization - asexual reproduction, independent assortment, crossing over between nonsister chromatids of homologous chromosomes, and random fertilization
- sexual reproduction, independent assortment, crossing over between nonsister chromatids of homologous chromosomes, and random fertilization
The egg (ovum) of a rabbit contains 22 chromosomes. How many chromosomes are in the somatic (body) cells of a rabbit? 44 11 132 88 22
44
Which of the following is a function of mitosis in humans? Increasing genetic variability Decreasing the number of chromosomes Multiplication of body cells Production of eggs Production of sperm
Multiplication of body cells
Somatic cells in animals differ from gametes in that somatic cells __________. replicate by a process called meiosis are always haploid do not contain sex chromosomes are important in sexual reproduction are all of the cells of the body except for the gametes & their precursors
are all of the cells of the body except for the gametes & their precursors
What is the result when a diploid cell undergoes meiosis? Four diploid cells Two haploid cells and two diploid cells Two haploid cells Four haploid cells Two diploid cells
four haploid cells
In meiosis, __________ of __________ cross over and form __________. nonhomologs; nonhomologous pairs; cohesion nonsister chromatids; homologous pairs; chiasmata nonsister chromatids; nonhomologous pairs; chiasmata sister chromatids; homologous pairs; chiasmata sister chromatids; nonhomologous pairs; chiasmata
nonsister chromatids; homologous pairs; chiasmata
At the end of mitosis, __________ daughter cells that are genetically __________ are formed, while at the end of meiosis, __________ daughter cells that are genetically __________ are formed. two; distinct; four; identical four; identical; two; distinct two; identical; two; distinct two; identical; four; distinct four; distinct; two; identical
two; identical; four; distinct
