Chapter 10 Practice Test
In a diploid set of chromosomes, one member of each pair of homologous chromosomes is derived from the father (paternal), and the other comes from the mother (maternal). If 2n = 6, what is the probability of obtaining a gamete in which all the chromosomes are paternal ones?
1/8
In humans, the haploid number of chromosomes is 23. Independent assortment has the possibility of producing __________ different types of gametes.
2^23 (for each gamete there are 2 possibilities for each chromosome and there are 23 different chromosomes per gamete)
The sexual cycle of the multicellular algal genus Fucus involves __________.
Mitosis, Meiosis, and Fertilization
The synaptonemal complex __________.
Physically connects homologous chromosomes during prophase I
Crossing over occurs during __________.
Prophase I
Synapsis occurs during __________.
Prophase I
What contributes to genetic variation in sexually reproducing species?
Random fertilization Independent assortment Crossing over
Although __________ is nearly universal among animals, bdelloid rotifers __________.
Sexual reproduction, reproduce asexually but can increase genetic variation present in a population by means of the uptake of DNA from other rotifers
What event occurs only during prophase I of the first meiotic division?
Synapsis of homologous pairs occur
How many genes are present in the human genome?
Tens of thousands
Diploid cells _______ divide by meiosis.
Can
Diploid cells _______ divide by mitosis.
Can
Haploid cells _______ divide by mitosis.
Can
Haploid cells _______ divide by meiosis.
Cannot
Regions of chromosomes where nonsister chromatids cross over are called __________.
Chiasmata
Chiasmata indicate where crossing over is occurring between homologs is an outcome of _______.
Crossing over
Formation of chromosomes containing paternal and maternal alleles is an outcome of _______.
Crossing over
The DNA is 2 non-sister chromatids is broken by specific proteins at exact points is an outcome of _______.
Crossing over
Spores and gametes are different in that __________.
Gametes can fuse to form a zygote, but spores can develop into independent organisms without first forming a zygote
Ignoring crossover, how many kinds of gametes can be produced by an organism with a diploid number of 8?
16
At the end of telophase I of meiosis and the first cytokinesis, there are __________.
2 haploid cells
Somatic cells in humans contain __________ set(s) of chromosomes and are therefore termed __________.
2, diploid
How many pairs of autosomes do humans have?
22
In a male mammal, every cell that undergoes meiosis gives rise to __________ sperm.
4
What is the result when a diploid cell undergoes meiosis?
4 haploid cells
The egg (ovum) of a rabbit contains 22 chromosomes. How many chromosomes are in the somatic (body) cells of a rabbit?
44
In a diploid cell containing 10 chromosomes, meiosis results in the formation of daughter cells containing __________ chromosomes.
5
Fertilization produces _______.
A diploid zygote
A karyotype is _______.
A display of all of an individual's chromosomes arranged in pairs
Although energetically more costly than asexual reproduction, sexual reproduction leads to different combinations of alleles that could provide adaptability in a changing environment reflects an _______.
Advantage that sexual reproduction has over asexual reproduction
Spores, multicellular diploid stage (sporophyte), zygote, and multicellular haploid stage (gametophyte) are all apart of the life cycle called _______.
Alternation of generations
Homologs separate and migrate toward opposite poles, guided by the spindle apparatus occurs during _______.
Anaphase I
Sister chromatids separate and migrate toward opposite poles occurs during _______.
Anaphase II
Sister chromatids __________.
Are identical copies of each other formed during DNA synthesis
A clone is the product of _______.
Asexual reproduction and mitosis
Nearly all life cycles have both haploid and diploid phases. Usually, the transition from haploid to diploid takes place __________.
At fertilization, when gametes fuse
Multiplication of body cells that are genetically identical to the parent cell is a function of mitosis in _______.
Humans
The random alignment of homologous pairs of chromosome at metaphase I is an outcome of _______.
Independent assortment
The major contribution of sex to evolution is that __________.
It increases genetic variation
When we say that an organism is haploid, we mean that __________.
Its cell has a single set of chromosomes
Undergoing two rounds of cytokinesis, introducing genetic variation among the daughter cells, ensuring that each daughter cell gets a single, complete set of chromosomes, decreasing the chromosome number to haploid all makes meiosis ________ and _______ than mitosis.
Lengthier, more complex
Humans have 46 chromosomes. This number of chromosomes will be found in __________.
Liver cells
What results in cells that contain half the parental chromosome number?
Meiosis
During ______, cohesion holds sister chromatids together along their lengths as _______ forms between homologs.
Meiosis I, chiasmata
During _______, cohesion holds the sister chromatids together at the centromeres pair to their separation at _______.
Meiosis II, metaphase II
In sexually reproducing species, the chromosome number remains stable over time because __________ and __________ always alternate.
Meiosis, fertilization
What is a locus?
The specific location of a gene along the length of a chromosome
The diploid number of chromosomes in a certain animal is 8 (2n = 8). How do the four pairs of homologous chromosomes align and separate during meiosis?
They align and assort independently to form any of 16 different combinations
Sexual and asexual reproduction are alike in that _______.
They can both occur in multicellular organisms
What is the function of meiosis?
To make cells with a haploid number of chromosomes