Week 9 Mitosis and Meiosis

Regarding meiosis I, which are correct? -Crossing over is effected by the synaptonemal complex. -Independent assortment means there is a 50% chance that a daughter cell will get the maternal chromosome of a certain homologous pair and a 50% chance that it will get the paternal chromosome. -Crossing over means a paternal chromatid is joined to a piece of maternal chromatid beyond the crossover point, and vice versa. -independent assortment ocurrs at metaphase I. -Independent assortment means a paternal chromatid is joined to a piece of maternal chromatid beyond the crossover point, and vice versa. -Crossing over means there is a 50% chance that a daughter cell will get the maternal chromosome of a certain homologous pair and a 50% chance that it will get the paternal chromosome. -Crossing over is effected by the spindle.

- Crossing over is effected by the synaptonemal complex. -Independent assortment means there is a 50% chance that a daughter cell will get the maternal chromosome of a certain homologous pair and a 50% chance that it will get the paternal chromosome. -Crossing over means a paternal chromatid is joined to a piece of maternal chromatid beyond the crossover point, and vice versa. -Independent assortment ocurrs at metaphase I.

Regarding meiosis I, which are correct? -Independent assortment is effected by the spindle. -Independent assortment means there is a 50% chance that a daughter cell will get the maternal chromosome of a certain homologous pair and a 50% chance that it will get the paternal chromosome. -Crossing over means a paternal chromatid is joined to a piece of maternal chromatid beyond the crossover point, and vice versa. -Crossing over occurs during Prophase I. -Independent assortment means a paternal chromatid is joined to a piece of maternal chromatid beyond the crossover point, and vice versa. -Crossing over means there is a 50% chance that a daughter cell will get the maternal chromosome of a certain homologous pair and a 50% chance that it will get the paternal chromosome. -Independent assortment occurs during Prophase I.

-Independent assortment is effected by the spindle. -Independent assortment means there is a 50% chance that a daughter cell will get the maternal chromosome of a certain homologous pair and a 50% chance that it will get the paternal chromosome. -Crossing over means a paternal chromatid is joined to a piece of maternal chromatid beyond the crossover point, and vice versa. -Crossing over occurs during Prophase I.

A haploid set of unreplicated chromosomes (n = 3) of the mosquito Aedes aegypti has a mass of 1.5 pg. What is the mass of DNA in a single Aedes aegypti cell at the end of telophase II? 1.5 pg 3 pg 4.5 pg 6 pg

1.5 pg

A haploid set of unreplicated chromosomes (n = 3) of the mosquito Aedes aegypti has a mass of 1.5 pg. What is the mass of DNA in a single Aedes aegypti cell in prophase II? 3 pg 1.5 pg 4.5 pg 6 pg

3 pg

The egg (ovum) of a rabbit contains 22 chromosomes. How many chromosomes are in the somatic (body) cells of a rabbit? 44 11 22 88 132

44

A haploid set of unreplicated chromosomes (n = 3) of the mosquito Aedes aegypti has a mass of 1.5 pg. What is the mass of DNA in a single Aedes aegypti cell in prophase I? 6 pg 1.5 pg 4.5 pg 3 pg

6 pg

__________ are a group of genetically identical individuals produced by a process called __________. Clones; asexual reproduction Clones; sexual reproduction Gametes; meiosis Gametes; asexual reproduction Homologs; meiosis

Clones; asexual reproduction

Regarding the role of cohesin protein in maintaining cohesion between sister chromatids, which of the following statements is false? -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. -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 -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. -None of the listed responses is false.

During meiosis II, cohesion holds sister chromatids together along their lengths as the second meiotic spindle forms.

What is the result when a diploid cell undergoes meiosis? Four haploid cells Two diploid cells Two haploid cells Four diploid cells Two haploid cells and two diploid cells

Four haploid cells

Which of the following occurs in meiosis, but not mitosis? Homologous chromosomes separate. The cells formed have the same combination of genes as found in the initial cell. The nuclear envelope disappears. Sister chromatids undergo disjunction. A spindle apparatus forms.

Homologous chromosomes separate.

In humans, which create cells with homologous chromosomes? Mitosis Fertilization Meiosis I Meiosis II

Mitosis Fertilization

Which of the following is a function of mitosis in humans? Multiplication of body cells Production of eggs Production of sperm Decreasing the number of chromosomes Increasing genetic variability

Multiplication of body cells

How many genes are present in the human genome? Tens of thousands 23 46 Hundreds A virtually infinite number

Tens of thousands

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 have genes for the same traits at the same loci. They are found in animal cells but not in plant cells. They pair up in prophase II. They are found in haploid cells. They are found in the cells of human females but not in human males.

They have genes for the same traits at the same loci.

Somatic cells in animals differ from gametes in that somatic cells __________. are all of the cells of the body except for the gametes and their precursors are always haploid replicate by a process called meiosis are important in sexual reproduction do not contain sex chromosomes

are all of the cells of the body except for the gametes and their precursors

Sister chromatids differ from nonsister chromatids in that sister chromatids __________. are products of the S phase of the cell cycle and are two copies of one chromosome always come from nonsister chromatids are part of nonhomologous chromosomal sets are part of only the maternal set are never found in the paternal set

are products of the S phase of the cell cycle and are two copies of one chromosome

A clone is the product of __________. asexual reproduction and mitosis asexual reproduction sexual reproduction mitosis meiosis sexual reproduction and meiosis

asexual reproduction and mitosis

Somatic cells in humans differs from gametes in that human somatic cells __________. contain two sets of each of the 23 chromosome types are always haploid replicate by a process called meiosis are important in sexual reproduction do not contain sex chromosomes

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 clones; mitotic division; diploid None of the listed responses is correct because only animals have zygotes.

diploid; fertilization; haploid

Allelic variation is an important source of __________ in a population. genetic diversity clonal diversity asexual reproduction mitosis None of the listed responses is correct.

genetic diversity

A pair of genetic structures carrying genes that control the same inherited characters are called __________. homologous chromosomes sister chromatids nonsister chromatids autosomes clones zygotes

homologous chromosomes

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 way in which somatic mutations can be inherited it provides a method to increase genetic variation and it is the only mechanism for species to reproduce 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; two consecutive cell divisions mitosis; two consecutive cell divisions meiosis; dividing without chromosome duplication mitosis; dividing without chromosome duplication mitosis; destroying one set of information prior to division

meiosis; two consecutive cell divisions

In meiosis, __________ of __________ cross over and form __________. nonsister chromatids; homologous pairs; chiasmata sister chromatids; homologous pairs; chiasmata nonhomologs; nonhomologous pairs; cohesion nonsister chromatids; nonhomologous pairs; chiasmata sister chromatids; nonhomologous pairs; chiasmata

nonsister chromatids; homologous pairs; chiasmata

The zipper-like complex that forms in meiosis occurs during __________ and is called the __________. prophase I; synaptonemal complex metaphase I; synaptonemal complex prophase II; meiotic complex metaphase II; meiotic complex prophase I; centromeric complex

prophase I; synaptonemal complex

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

Somatic cells in humans contain __________ set(s) of chromosomes and are therefore termed __________. two; diploid one; diploid two; haploid one; haploid three; triploid

two; diploid

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; identical; four; distinct four; identical; two; distinct four; distinct; two; identical two; distinct; four; identical two; identical; two; distinct

two; identical; four; distinct