Biology 1001-Ch. 9
Meiosis starts with a single diploid cell and produces - two diploid cells. - eight haploid cells. - two haploid cells. - four diploid cells. - four haploid cells.
four haploid cells. Meiosis produces four haploid cells.
The ease with which humans travel across the globe is likely to increase _____. - natural selection - gene flow - mutation - genetic drift - all of these
gene flow When people travel or migrate, they take their alleles with them.
All the genes in a population are that population's _____. - fitness - gene pool - Hardy-Weinberg - genotype - phenotype
gene pool All the alleles of all the genes of a population make up a gene pool.
During _____ a spindle forms in a haploid cell. - prophase I - metaphase II - anaphase II - prophase II - telophase I and cytokinesis
prophase II
Which of these individuals is a homozygous genotype? - AG - AA - Aa - aG - Gg
AA When both of the alleles of a given gene pair are the same, the individual is homozygous for that gene.
Cytokinesis often, but not always, accompanies _____. - anaphase - telophase - interphase - prometaphase - metaphase
telophase
Which phase of mitosis comes last during cell division? - interphase - anaphase - cytokinesis - telophase - G1
telophase
When the sister cells are completely divided through Cytokinesis. - prophase - prometaphase - anaphase - metaphase - telophase
telophase During telophase both nuclear envelopes and nucleoli re-form.
At the end of _____ and cytokinesis, haploid cells contain chromosomes that each consist of two sister chromatids. - metaphase II - telophase - telophase II - telophase I - interphase
telophase I
At the end of _____ and cytokinesis there are four haploid cells. - prophase II - prophase I - telophase II - anaphase I - interphase
telophase II
Four haploid cells are present at the end of _____ and _____. - telophase II - telophase I and cytokinesis - telophase II and cytokinesis - telophase I - telophase and cytokinesis
telophase II and cytokinesis
During _____ both the contents of the nucleus and the cytoplasm are divided. - mitosis - G1 - S - G2 - the mitotic phase
the mitotic phase The mitotic phase encompasses both mitosis and cytokinesis.
Genetic is a process based on - mutation - emigration - differential reproductive success correlated to the relationship between a phenotype and the environment - the role of chance - immigration
the role of chance Genetic drift requires a small sample size.
A mutation occurs when _____. - individuals leave a population - individuals enter a population - there is a change in the DNA sequence of a gene - some individuals leave more offspring than other individuals - population sizes are small
there is a change in the DNA sequence of a gene
A cell preparing to undergo meiosis duplicates its chromosomes during - meiosis II. - prophase I. - interphase. - metaphase I. - anaphase I.
Chromosomes are duplicated during interphase.
Which of the following is separated during anaphase I? - telomeres - homologous chromosomes - nuclei - centromeres - centrioles - sister chromatids
homologous chromosomes Homologous chromosomes are separated in anaphase I and sister chromatids are separated in anaphase II.
Gametes are produced by _____. - the cell cycle - fertilization - meiosis - asexual reproduction - mitosis
meiosis Meiosis produces haploid gametes from a diploid parental cell.
Spindle fibers attach to kinetochores during _____. - interphase - anaphase - prometaphase - telophase - metaphase
prometaphase
When the chromosomes break the nuclear envelope, and attach to microtubules - prometaphase - cytokinesis as it occurs in plant cells - metaphase - interphase - anaphase
prometaphase
Chromosomes become visible during _____. - metaphase - interphase - prometaphase - anaphase - prophase
prophase
Modern travel along with migration reduces the probability of _____ having an effect on the evolution of humans. - natural selection - mutation - disease - genetic drift - gene flow
genetic drift Modern travel and migration decreases the chances of there being a small, isolated population.
During _____ the cell grows and replicates both its organelles and its chromosomes. - S - G1 - cytokinesis - interphase - mitosis
interphase
Nucleoli are present during _____. - prophase - interphase - anaphase - metaphase - prometaphase
interphase
Which of these phases of the cell cycle is most similar between a cell that will divide by mitosis and one that will divide by meiosis? - telophase - interphase - anaphase - prophase - metaphase
interphase In either case, the DNA must be duplicated in order to divide the cells.
What word is used to describe the exact position of a gene on a chromosome? - locus - centromere - allele - chromatid - telomere - histone
locus The locus of a gene is its exact position on the chromosome.
When chromosomes align laterally (along the metaphase plate: imaginary line located midway between the poles of the duplicated chromosomes and the original chromosomes), before they separate. - anaphase - telophase - metaphase - prophase - prometaphase
metaphase
Homologous pairs of chromosomes are lined up independently of other such pairs during _____. - metaphase II - anaphase I - metaphase I - telophase II - prophase II
metaphase I
During _____ chromosomes align single file along the equator of a haploid cell. - metaphase I - anaphase I - prophase I - metaphase II - telophase I and cytokinesis
metaphase II
Meiosis I produces _____ cells, each of which is _____. - four ... haploid - two... identical to the other - two ... haploid - two... diploid - four ... diploid
two ... haploid At the end of meiosis I there are two haploid cells.
During prophase a homologous pair of chromosomes consists of _____. - one chromosome and two chromatids - four chromosomes and two chromatids - two chromosomes and four chromatids - two chromosomes and two chromatids - one chromosome and four chromatids
two chromosomes and four chromatids At this point each of the chromosomes consists of two chromatids.
Stages of the Cell Cycle
-Most of a cell's life is spent in -interphase-, when growth occurs. Cells that are about to divide replicate their DNA -In -prophase-, microtubules form the mitotic spindle, and the nuclear envelope breaks up -At -metaphase-, the mitotic spindle is fully forms and chromosomes are lined up in the center of the cell. -In -anaphase-, sister chromatids separate and become full fledged chromosomes that move to opposite poles. -In -telophase-, chromosomes become less condensed and new nuclear envelopes form. -In -cytokinesis-, the cytoplasm divides.
Martian invaders come to Earth to conduct tests on human biology students. A Martian tells you that, in his species, n=62. Assuming their chromosomes are like human chromosomes, he then asks you how many chromosomes are present in each cell of his finger. How do you reply? - 124 - 31 - 248 - 62
124 The Martian gave you the haploid number. The cells of his finger are likely diploid, so they have twice the haploid number.
A diploid organism whose somatic (nonsex) cells each contain 32 chromosomes produces gametes containing _____ chromosomes. - 16 - 8 - 64 - 30 - 32
16
In human gamete production there is an average of _____ crossover events per chromosome pair. - 0-1 - 2-3 - 9-10 - 10+ - 5-6
2-3 These crossover events increase the genetic variation among gametes.
Normal human gametes carry _____ chromosomes. - 23 - 46 - 5 - 23 pairs of - 46 pairs of
23 This is the number of chromosomes in a single set of human chromosomes.
In the laboratory fruit fly, n is 4. How many different chromosome sets can be produced by one fly, excluding crossing over? - 2^8 variations - 2^46 variations - 2^4 variations - 4^2 variations - 4^23 variations - 2^23 variations
2^4 variations Among each chromosome pair, a choice can be made. This means 2 to the power of n unique combinations exist.
Every few years a giant axe chops off the head of every person who is over 6 feet tall. How will this affect the human population? - Genetic drift will play less of a role in the evolution of humans. - Gene flow will increase. - Alleles that promote "tallness" will decrease in frequency. - The mutation rate will increase. - It will increase in number since shorter people use fewer resources than taller people.
Alleles that promote "tallness" will decrease in frequency. A reduction in "tallness" alleles is the change expected as a result of this type of selection.
The sister chromatids separate and begin moving toward opposite poles of the cell during which phase of mitosis? - Anaphase - Prophase - Interphase - Metaphase - Telophase
Anaphase Sister chromatids separate and start their migration toward opposite poles during anaphase.
What is the most important difference between asexual reproduction and sexual reproduction? - Asexual reproduction only requires one organism. Sexual reproduction requires two organisms. - Asexual reproduction requires DNA replication. Sexual reproduction does not. - Asexually produced cells are genetically identical. Sexually produced cells are genetically unique. - Asexual reproduction is more common than sexual reproduction. - Asexual reproduction produces two daughter cells. Sexual reproduction produces one daughter cell.
Asexually produced cells are genetically identical. Sexually produced cells are genetically unique. The purpose of sexual reproduction is primarily to create genetically unique individuals.
Phases of the Cell Cycle
G1 Phase S Phase Interphase G2 Phase Mitotic Phase Mitosis Cytokinesis
Centrioles duplicate during the cell cycle. Given your knowledge of the cell cycle, when would you guess that the duplication of centrioles occurs? - G1 phase - mitosis - prophase - telophase - G2 phase - metaphase
G1 phase When the cell makes the decision to divide, the centrioles are immediately duplicated.
Which of the following do all three life cycles have in common? - Organisms spend the majority of their time as diploid organisms. - Male gametes are sperm and female gametes are eggs. - Gametes fuse to make a zygote. - Mitosis produces gametes. - Meiosis produces gametes.
Gametes fuse to make a zygote. All of the life cycles fuse two haploid gametes to make a diploid zygote.
How do the genes in DNA control cell function? - Genes carry the instructions for making proteins. - Genes carry the instructions for cell division. - Genes carry the instructions for copying DNA. - Genes carry the instructions for mutating cells. - Genes carry the instructions for running the cell.
Genes control cells by controlling protein production
How are homologous chromosomes defined? - Homologous chromosomes contain the same genes, but may contain different alleles. - Homologous chromosomes contain the same alleles, but each allele is at a different locus. - Homologous chromosomes contain the same alleles, but may contain different genes. - Homologous chromosomes contain the same genes and the same alleles. - Homologous chromosomes contain the same genes, but each gene is at a different locus.
Homologous chromosomes contain the same genes, but may contain different alleles. Homologous chromosomes have identical genes, but may have different varieties of that gene (brown hair vs. black hair).
During prophase I of meiosis, - there are two daughter cells, each with 23 chromosomes. - the homologous chromosomes separate and move towards opposite poles. - chromosome pairs are positioned in the middle of the cell. - homologous chromosomes stick together in pairs. - there are four haploid daughter cells.
Homologous chromosomes stick together in pairs during prophase I.
Which of the following is a correct description of meiosis? - Meiosis is one round of DNA replication followed by one round of cell division. - Meiosis is two rounds of DNA replication followed by two rounds of cell division. - Meiosis is one round of cell division without DNA replication. - Meiosis is one round of DNA replication followed by two rounds of cell division. - Meiosis is two rounds of cell division without DNA replication.
Meiosis is one round of DNA replication followed by two rounds of cell division. Meiosis still involves DNA replication and relies on two divisions to reach the haploid number.
The correct order of events during meiosis is - prophase I, anaphase I, telophase I, metaphase I, meiosis II. - metaphase I, prophase I, telophase I, anaphase I, cytokinesis, meiosis II. - metaphase I, prophase I, anaphase I, telophase I, cytokinesis, meiosis II. - prophase I, anaphase I, metaphase I, telophase I, meiosis II, cytokinesis. - prophase I, metaphase I, anaphase I, telophase I, cytokinesis, meiosis II.
Meiosis starts with prophase I and continues with metaphase I, anaphase I, telophase I, and cytokinesis. This is followed by meiosis II.
The chromosomes line up in the center of the cell during which phase of mitosis? - Anaphase - Interphase - Metaphase - Telophase - Prophase
Metaphase Metaphase occurs in the middle of mitosis, when the chromosomes line up in the middle of the cell.
The centrosomes move away from each other and the nuclear envelope breaks up during which phase of mitosis? - Prophase - Interphase - Anaphase - Telophase - Metaphase
Prophase Prophase is the first phase of mitosis, when the centrosomes begin moving toward opposite poles and the nuclear envelope breaks up.
Which of the following sentences uses the words chiasma, recombination, and crossing over correctly? - Chiasma occurs when sister chromatids with different alleles recombine DNA by crossing over. - Chiasma occurs when homologous chromosomes with similar alleles recombine DNA by crossing over. - Recombination occurs when sister chromatids with different alleles exchange DNA by crossing over at a point called a chiasma. - Recombination occurs when homologous chromosomes with different alleles exchange DNA by crossing over at a point called a chiasma. - Crossing over occurs when sister chromatids with different alleles exchange DNA by recombining at a point called a chiasma.
Recombination occurs when homologous chromosomes with different alleles exchange DNA by crossing over at a point called a chiasma. Remember that different alleles must be involved before crossing over can be called recombination
During meiosis, segments of nonsister chromatids can trade places. This recombination of maternal and paternal genetic material is a key feature of meiosis. During what phase of meiosis does recombination occur? - meiosis II. - prophase I. - Metaphase I. - telophase I. - anaphase I.
Segments of nonsister chromatids trade places during prophase I, resulting in recombination.
What is the most important reason for sexual reproduction? - Sexual reproduction is necessary to make new individuals of a species. - Sexual reproduction results in better parental care than asexual reproduction. - Sexual reproduction creates genetically unique individuals. - Sexual reproduction creates haploid organisms. - Sexual reproduction creates new individuals of a species more quickly.
Sexual reproduction creates genetically unique individuals. The products of asexual reproduction are clones of the parent cells. Genetic uniqueness allows a species to adapt better to its environment.
What is the function of the telomere? - Telomeres connect two sister chromatids after DNA replication. - Telomeres signal the cell when to begin division. - Telomeres coil up the DNA to make it take up less room. - Telomeres prevent the ends of chromosomes from being damaged. - Telomeres copy the DNA. - Telomeres contain unique genes.
Telomeres prevent the ends of chromosomes from being damaged. Telomeres prevent the shortening of chromosomes during replication and the accidental fusion of two chromosomes at their ends.
The chromosomes arrive at the poles and nuclear envelopes form during which phase of mitosis? - Prophase - Telophase - Metaphase - Interphase - Anaphase
Telophase Telophase is the final phase of mitosis, when the chromosomes have arrived at the poles and the nuclear envelopes of the two new cells form.
How do cells fit long pieces of DNA into a compartment as small as the nucleus? - The DNA is wrapped around histones. - The DNA is cut into smaller pieces. - The DNA is shortened by abbreviating gene information. - The DNA is wrapped around the nucleus. - The DNA is packaged inside centromeres.
The DNA is wrapped around histones. The DNA is wrapped and coiled like a long extension cord around a cord reel.
Compare the cells of a woman's leg muscle to the cells of a baby growing inside her womb. What is the most important difference between them? - The chromosomes in the cells of the woman's leg muscle are genetically identical to the rest of her body. The baby's cells contain only half of the mother's chromosomes. - The cells of the woman's leg muscle are larger than the cells of the baby. - The cells of the woman's leg muscle have differentiated. The cells of the baby have not. - The cells of the woman's leg muscle are not dividing. The cells of the baby are dividing. - The cells of the woman's leg muscle are less important than the cells of the baby. - The cells of the woman's leg muscle are diploid. The cells of the baby are haploid.
The chromosomes in the cells of the woman's leg muscle are genetically identical to the rest of her body. The baby's cells contain only half of the mother's chromosomes. A baby is genetically unique from its mother. The cells of a muscle contain the same DNA found in the rest of the body.
What must happen before a cell can begin mitosis? - The nuclear envelope must break up. - A mitotic spindle must form. - The nucleus must divide in two. - The chromosomes must be duplicated. - The sister chromatids must be separated.
The chromosomes must be duplicated. Before mitosis can begin, the chromosomes, or genetic material, must be copied, which occurs during interphase.
Many science fiction books and movies have suggested that human cloning will be a dominant mode of reproduction in the future. Which of the following presents a good scientific argument against this practice? - Reproduction by generating clones does not occur outside of the laboratory, so there must be significant disadvantages. - We cannot properly test the effects of human cloning on an individual and it would be irresponsible to attempt such testing. - The large percentage of species making use of sexual reproduction suggests that maintaining genetic variation is necessary for the success of a species. - Human clones have never existed and we cannot predict how their presence would affect our society. - Human cloning is wrong because each child is unique and this would create a society where many people were identical.
The large percentage of species making use of sexual reproduction suggests that maintaining genetic variation is necessary for the success of a species. The benefits of a genetically varied species have been proven time and again. In fact, evidence has shown that genetic variation is more important than total number of individuals to the survival of an endangered species.
Which of the following events occurs during prophase? - The spindle microtubules form. - DNA replication occurs. - The cell grows. - The cell is divided in half. - Sister chromatids separate. - Chromosomes line up in the center of the cell.
The spindle microtubules form. The spindle microtubules must form before DNA can be sorted and divided.
What do the three major checkpoints for cell division have in common? -They all stop the cell from dividing when too small. - They all stop the cell cycle before mitosis. - They all focus on DNA and chromosomes. - They all rely on Cdk proteins to stop the cell cycle. - They all prevent cells from becoming haploid.
They all focus on DNA and chromosomes. All three checkpoints focus on the readiness of the cell based on DNA replication and sorting of the chromosomes.
Which of the following is the most important for generating the most genetic variability in a species? - more than one chromosome - ability to fuse haploid gametes to form a new individual - asexual reproduction - crossing over - mitosis - recombination
ability to fuse haploid gametes to form a new individual The ability to combine different sets of alleles into one individual is most important to generating diversity.
Which life cycle do plants make use of? - alternation of generations - alternation of divisions - diploid life cycle - binary life cycle - haploid life cycle
alternation of generations Each species has a diploid plant and a haploid plant and the two are unique from each other.
Centromeres divide and sister chromosomes become full-fledged chromosomes during _____. - metaphase - anaphase - telophase - interphase - prometaphase
anaphase
When the separate chromosomes are being pulled from one place to another? - anaphase - telophase - interphase - prophase - metaphase
anaphase During anaphase centromeres come apart, and sister chromatids become full-fledged chromosomes, which migrate to opposite poles of the cell.
Homologous chromosomes migrate to opposite poles during _____. - metaphase II - metaphase I - anaphase I - prophase II - telophase II and cytokinesis
anaphase I
During _____ sister chromatids separate and migrate to opposite poles. - metaphase I - prophase I - prophase II - interphase - anaphase II
anaphase II
Which of these phases is the most different between mitosis and meiosis? - prophase and prophase II - telophase and telophase I - anaphase and anaphase I - anaphase and anaphase II - metaphase and metaphase II
anaphase and anaphase I In anaphase, sister chromatids separate. In anaphase I, homologous pairs separate.
Which cellular structure contributes to the biggest difference between mitosis in plants and mitosis in animals? - cell wall - centrioles - plasma membrane - chloroplasts - mitochondria
cell wall The cell wall of plants is rigid, preventing the cell from being pinched in half by a microfilament belt.
Which specific structure must separate during anaphase in order for sister chromatids to begin moving toward opposite poles? - telomeres - centromeres - chiasmata - spindle microtubules - centrioles - kinetichores
centromeres The centromere is the point of attachment between the two sister chromatids.
Which of the following is produced in response to growth factors binding to surface receptors? - Cdk proteins - cyclins - microtubules - growth factors - cyclin-dependent kinases - phosphorylates
cyclins Cyclins are produced after surface receptors bind growth factors
At the end of the mitotic (M) phase, the cytoplasm divides in a process called - cytokinesis - meiosis - telophase - condensation - replication
cytokinesis Cytokinesis is the division of the cytoplasm that occurs in conjunction with telophase, the last phase in mitosis.
When the two "circular" cells attached become sister cells? - cytokinesis as it occurs in plant cells - cytokinesis as it occurs in animal cells - prophase - metaphase - prometaphase
cytokinesis as it occurs in animal cells Cytokinesis in animal cells involves the formation of a cleavage furrow.
When the two "square" cells attached become sister cells? - prometaphase - anaphase - metaphase - cytokinesis as it occurs in plant cells - prophase
cytokinesis as it occurs in plant cells
Meiosis II typically produces _____ cells, each of which is _____. - four ... identical to the other - four ... haploid - four ... diploid - two ... haploid - two... diploid
four ... haploid At the end of meiosis II there are typically 4 haploid cells.
Crossing over, resulting in an increase in genetic variation, occurs between _____. - nonsister chromatids of nonhomologous chromosomes - sex cells and somatic cells - sister chromatids of nonhomologous chromosomes - sister chromatids of homologous chromosomes - nonsister chromatids of homologous chromosomes
nonsister chromatids of homologous chromosomes This process produces chromosomes containing genes inherited from both parents.
Compare prokaryotic cells to eukaryotic cells. Which difference between these two cell types affects cell division the most? - no nucleus vs. nucleus - no organelles vs. organelles - plasma membrane vs. cell wall - circular chromosomes vs. linear chromosomes - one chromosome vs. many chromosomes
one chromosome vs. many chromosomes The complexity of mitosis (and meiosis) is based mostly off of the need to assure that each cell gets one copy of each chromosome. Prokaryotes only have one chromosome to copy and sort.
When the chromosomes become visible? - interphase - telophase - prometaphase - prophase - anaphase
prophase Events of prophase include the condensation of chromatin and the dispersal of nucleoli.
Synapsis occurs during _____. - metaphase II - anaphase II - prophase II - telophase I and cytogenesis - prophase I
prophase II
The events of ____ are essentially the same as those of mitotic prophase except that prophase II cells are haploid. - prophase I - telophase I and cytokinesis - anaphase II - prophase II - telophase II and cytokinesis
prophase II
