Honors Biology Chapter 8
A cell biologist carefully measured the quantity of DNA in grasshopper cells growing in cell culture. Cells examined during the G2 phase of the cell cycle contained 200 units of DNA. What would be the amount of DNA in one of the grasshopper daughter cells? >200 units >400 units >100 units >50 units
100 units
There are species of coffee plant with 22, 44, 66, and 88 chromosomes. All but one of these species is considered to be an example of polyploidy. Plant geneticists believe that the original haploid number of chromosomes in coffee was _____. >11 >44 >22 >23
11
A diploid organism whose somatic (nonsex) cells each contain 32 chromosomes produces gametes containing _____ chromosomes. >30 >32 >16 >64 >8
16
Baker's yeast is an organism with 32 chromosomes that can perform asexual or sexual reproduction and exist as both a diploid and haploid cell. After meiosis, how many chromosomes will be present in each cell? >32 >64 >16 >8
16
How many pairs of autosomes do humans have? >2 >1 >23 >22
22
Normal human gametes carry _____ chromosomes. >5 >23 pairs of >23 >46 >46 pairs of
23
A certain species of animal has six pairs of chromosomes. How many DNA molecules are present in the nuclei of these animals during G2 phase? >12 >24 >48 >6
24
A human somatic cell contains _____ chromosomes. >23 >2n >46 >47
46
Each cell in an individual with Down syndrome contains _____ chromosomes. >24 >47 >46 >45
47
A human bone marrow cell, in prophase of mitosis, contains 46 chromosomes. There are _____ chromatids. >46 >23 >92 >23 or 46, depending on when during prophase you look
92
Which of the following checkpoints does not occur late in G1? >A check that chromosome replication has been successfully completed >A check that growth factors are present >A check that nutrients are sufficient >A check that the cell is large enough for division
A check that chromosome replication has been successfully completed
Which event occurs only during prophase I of the first meiotic division? >Replication of DNA takes place. >Nuclear membrane breaks down. >Synapsis of homologous pairs occurs. >Chromosomes contain two chromatids attached to the same centromere.
Synapsis of homologous pairs occurs.
The phase of mitosis during which the chromosomes move toward separate poles of the cell is _____. >telophase >metaphase >anaphase >cytokinesis
anaphase
Single sister chromatids are found in cells at mitotic _____. >anaphase and telophase >prophase and telophase >metaphase and anaphase >prophase and anaphase
anaphase and telophase
A benign and a malignant tumor differ in that _____. >cells of a benign tumor spread by metastasis and cells of a malignant tumor spread by expansion of the tumor mass >benign tumors are harmless and malignant tumors are lethal >cells of a benign tumor remain within the tumor, whereas cells of a malignant tumor can spread to other body tissues >a benign tumor only forms from solid tissues such as skin or muscle and a malignant tumor only forms from blood and lymphatic tissue
cells of a benign tumor remain within the tumor, whereas cells of a malignant tumor can spread to other body tissues
What happens during prophase I
chromatin condenses
At the conclusion of meiosis I, the daughter cells are _____. >diploid and the sister chromatids have separated >haploid and the tetrads are still joined >diploid and the tetrads have separated >haploid and the sister chromatids are joined
haploid and the sister chromatids are joined
During _____ the cell grows and replicates both its organelles and its chromosomes. >mitosis >cytokinesis >interphase >G1 >S
interphase
Order the phases of cell cycle
interphase, prophase, metaphase, anaphase, telophase
What happens to the DNA during interphase?
it replicates
When we say that an organism is haploid, we mean that _____. >it has one half of a chromosome >its cells each have one chromosome >its cells each have two sets of chromosomes >its cells each have one set of chromosomes
its cells each have one set of chromosomes
What happens during synapsis?
ma and pa chromosomes pair
The term binary fission is best applied to _____. >prokaryotes >plants >nuclear chemistry >mitosis
prokaryotes
In the telophase of mitosis, the mitotic spindle breaks down and the chromatin uncoils. This is essentially the opposite of what happens in _____. >metaphase >interphase >anaphase >prophase
prophase
Crossing over occurs during _____. >prophase I >metaphase I >anaphase I >prophase II
prophase I
Crossing over occurs during _____. >prophase I >metaphase II >metaphase I >prophase II
prophase I
First stage of meiosis?
prophase I
Which of the following shows mitosis in the correct chronological order? >telophase, prophase, anaphase, prometaphase, metaphase >prophase, prometaphase, metaphase, anaphase, telophase >prometaphase, metaphase, prophase, telophase, anaphase >anaphase, prometaphase, metaphase, prophase, telophase
prophase, prometaphase, metaphase, anaphase, telophase
What happens during G2?
release of chemicals, grows even larger
In meiosis II, _____. >sister chromatids are separated >chromosome number is reduced from diploid to haploid >chromosomes cross over to exchange genetic information >homologous chromosomes pair to ensure their even distribution to daughter cells
sister chromatids are separated
What do haploid gametes form?
zygotes
At the end of telophase I of meiosis, as cytokinesis occurs, there are _____. >two haploid cells >two diploid cells >one haploid ovum and three polar bodies >four haploid cells
two haploid cells
What is the full name of G1?
Growth and normal metabolic roles
What is the full name of G2?
Growth and preperation for meiosis
During binary fission, the replicated bacterial chromosome attaches to the plasma membrane by specialized anchor proteins. What is the purpose of this attachment between chromosome and membrane? >It ensures the formation of two complete nuclei around each of the chromosomes. >It ensures the separation of the replicated chromosomes as new membrane is made. >It causes the cell to elongate. >This keeps the separate chromosomes together.
It ensures the separation of the replicated chromosomes as new membrane is made.
What is the difference between a benign tumor and a malignant tumor? >Benign tumors will not kill you; malignant tumors will. >Benign tumors metastasize; malignant tumors do not. >Benign tumors are a mass of essentially abnormal cells; malignant tumors are an abnormal mass of essentially normal cells. >Benign tumors do not metastasize; malignant tumors do.
Benign tumors do not metastasize; malignant tumors do.
In the laboratory, cancer cells fail to show density-dependent inhibition of growth in cell culture. What is one explanation that could account for this? >Cancer cells have inactive receptors for growth factors. >Cancer cells are unable to attach to a surface and grow. >Cancer cells continuously secrete growth factors into the cell culture medium. >Cancer cells continue to die at a rate that is equal to their growth.
Cancer cells continuously secrete growth factors into the cell culture medium
Which of the following occurs during mitosis? >Organelles replicate. >Chromosomes replicate. >Two genetically different daughter cells result. >Chromatids separate.
Chromatids separate.
Which of the following occurs during mitosis? >Organelles replicate. >Chromosomes replicate. >Two genetically different daughter cells result. >Chromatids separate.
Chromatids separate.
What happens during S?
DNA is synthesized
Which of the following statements correctly describes the timing of DNA synthesis? >DNA is synthesized in the S phase of interphase. >DNA is synthesized in G2 of interphase immediately preceding mitosis. >DNA is synthesized only during mitosis. >DNA is synthesized continuously.
DNA is synthesized in the S phase of interphase.
What is the full name of S?
DNA replication
Scientists commonly choose white blood cells that are going through mitosis to prepare karyotypes. Why? >During mitosis, chromosomes are more condensed than during interphase. >Cells in mitosis have the fewest chromosomes, thus simplifying karyotype analysis. >More cells are in mitosis than any other stage of the cell cycle, making it easier to obtain mitotic cells for study. >Cells in mitosis contain the greatest number of chromosomes, thus providing more material for study.
During mitosis, chromosomes are more condensed than during interphase.
Why are individuals with an extra chromosome 21, which causes Down syndrome, more numerous than individuals with an extra chromosome 3 or chromosome 16? >There are probably more genes on chromosome 21 than on either chromosomes 3 or 16. >Nondisjunction of chromosomes 3 and 16 probably occurs more frequently. >Down syndrome results in more serious symptoms than either trisomy 3 or trisomy 16. >Extra copies of the other somatic chromosomes are probably fatal.
Extra copies of the other somatic chromosomes are probably fatal.
True or false. Mitosis takes place during M phase of the cell cycle, which is longer than interphase. >True >False
False
Consider the cell cycle shown below. Cells will usually divide if they receive the proper signal at a checkpoint in the _____ phase of the cell cycle. >M >S >G1 >G2
G1
When examining cells in the laboratory, you notice that a particular cell has half as much DNA as the surrounding cells. It appears that this cell's cell cycle halted at checkpoint _____. >G0 >G2 >M phase >G1
G1
Name the stages of interphase
G1, S, G2
What syndrome corresponds with: XXY?
Klinefelter syndrome
Which of the following is a key difference between meiosis and mitosis? >Synapsis occurs. >Chromosomes align at the metaphase plate. >Chromosomes migrate to opposite poles. >Chromosomes condense.
Synapsis occurs.
The M phase of mitosis and M phase of meiosis both occur after interphase. However, the two processes differ in the arrangement and behavior of their chromosomes. How? >The centromeres of all chromosomes align on the metaphase plate in meiosis and on opposite sides of the metaphase plate in mitosis. >Homologous chromosomes pair up in mitosis, but not in meiosis. >In meiosis, homologous chromosomes do not cross over; in mitosis, they do. >The pairing up of homologous chromosomes and crossing over only occur during meiosis.
The pairing up of homologous chromosomes and crossing over only occur during meiosis.
Within one chromosome, what is the relationship between the sequence of bases in DNA of one sister chromatid compared to the other? >The sequences are similar, but not identical. >The sequence in one chromatid is complementary to the sequence in the other. >The sequences are unrelated. The sequences are identical.
The sequences are identical.
Although in humans there are 22 pairs of autosomal chromosomes, only three different chromosomal trisomies are commonly seen in newborns. Of the remaining 19 autosomes, many trisomies have not been seen in newborns. Why not? >Trisomy for these autosomal chromosomes has no effect and therefore would never be noticed. >Trisomy for these other autosomal chromosomes occurs so rarely that it has never been documented. >These autosomal chromosomes do not contain the same type of DNA or protein that makes up chromosomes susceptible to trisomy. >Trisomy for the other autosomal chromosomes is often lethal, and the affected embryos are miscarried.
Trisomy for the other autosomal chromosomes is often lethal, and the affected embryos are miscarried.
What syndrome corresponds with: Xo
Turners syndrome
In theory, when a nondisjunction for chromosome 18 occurs during meiosis I, four gametes can be produced. If these gametes are fertilized with unaffected gametes from the second parent, what observations would you make concerning the resulting embryos? >Two of the embryos will be trisomic for chromosome 18, and two will contain a single copy of chromosome 18. >Two of the embryos will be trisomic for chromosome 18, and two will be normal. >All four embryos will be trisomic for chromosome 18. >Two of the embryos will be normal, and two will contain a single copy of chromosome 18.
Two of the embryos will be trisomic for chromosome 18, and two will contain a single copy of chromosome 18.
Which of the following indicates Turner syndrome? >XXX >XO >XYY >XXY
XO
Which of the following is a normal human female? >XXX >X >XX >XXY
XX
What happens during G1?
absorbing nutrients, grows larger, additional organelles are created
Crossing over is important because it _____. >prevents variation in gametes >ensures that homologous chromosomes pair up >allows the exchange of genes between homologous chromosomes >holds tetrads together
allows the exchange of genes between homologous chromosomes
The function of mitosis is to produce daughter cells that _____. >have a random assortment of maternal and paternal chromosomes >have half the number of chromosomes >are genetically identical to the parent cell (assuming no mutation has occurred) >have the same number of chromosomes as the parent cell but not the same genetic content
are genetically identical to the parent cell (assuming no mutation has occurred)
In many organisms, including humans, chromosomes are found in homologous pairs. Homologous chromosomes _____. >have roughly similar arrangements of their genes, but some versions of the genes may differ between the chromosomes >are similar in size and shape, but this deceptive similarity has nothing to do with placement of gene arrangement or type >are identical both in the arrangement of their genes and in every version of every gene >are identical in the arrangement of their genes, but some versions of the genes may differ between the chromosomes
are identical in the arrangement of their genes, but some versions of the genes may differ between the chromosomes
Define mitosis
asexual reproduction
The creation of genetically identical organism from one parent is...
asexual reproduction
Define meiosis
basically sexual reproduction
Which of the following conditions would result in inhibition of cell division due to density-dependent factors? >presence of growth factors >being completely surrounded by other cells >being attached to other cells of the same tissue >being attached to an extracellular surface
being completely surrounded by other cells
Asexual and sexual reproduction differ in that sexual reproduction _____. >is the only way multicellular organisms can reproduce >will produce offspring identical to the parents >can produce great variation among the offspring is the only way single-celled organisms can reproduce
can produce great variation among the offspring
What is the typical result when a diploid cell undergoes meiosis? >four haploid cells >two haploid cells >two diploid cells >four diploid cells
four haploid cells
A cell is treated with a drug that prevents the formation of intracellular (within the cell) vesicles. Which of the following processes would be blocked? >separation of eukaryotic chromosomes at anaphase >cytokinesis in a plant cell >alignment of eukaryotic chromosomes at the metaphase plate >cytokinesis in an animal cell
cytokinesis in a plant cell
Cytokinesis refers to _____. >division of the cell outside the nuclear material >division of all the parts of the cell >cell movement >division of the nucleus
division of the cell outside the nuclear material
Observations of cancer cells in culture support the hypothesis that cancer cells _____. >exhibit anchorage dependence >produce molecules that inhibit the growth factors required for cell division >divide in a controlled manner >do not exhibit density-dependent inhibition
do not exhibit density-dependent inhibition
Chromatids form _____. >during the S phase >during G2 >at the start of mitosis >during G1
during the S phase
True or False: Asexual reproduction creates genetic diversity.
false
The diploid phase of the human life cycle begins with _____. >mitosis >fertilization >meiosis >the first division of the zygote
fertilization
The function of meiosis is to make _____. >four cells with the same chromosome number as the parent cell >exact copies of the parent cell >one cell with twice the number of chromosomes as the parent cell >four cells with a haploid number of chromosomes
four cells with a haploid number of chromosomes
In humans, the _____ determines the sex of the offspring because _____. >male ... the male can contribute either an X or a Y chromosome >female ... only the female provides cytoplasm to the zygote >male ... the sperm can fertilize either a female egg or a male egg >female ... only the female has two functional sex chromosomes
male ... the male can contribute either an X or a Y chromosome
Cell devision -> four daughter cells w/ half the chromosome of the parent cell
meiosis
Gametes are produced by _____. >meiosis >fertilization >mitosis >the cell cycle >asexual reproduction
meiosis
Variation occurs when chromosomes are shuffled in _____. >genetic drift >meiosis >mutation >mitosis
meiosis
Name the two divisions of meiosis
meiosis I, meiosis II
Which of the following is a correct representation of an event that occurs in mitosis? >prophase - chromosomes uncoil. >metaphase - chromosomes line up on the equatorial plane. >anaphase - the nuclear envelope disappears. >prometaphase - there is movement of the chromosomes to the poles.
metaphase - chromosomes line up on the equatorial plane.
After fertilization, the resulting zygote begins to divide by _____. >meiosis >binary fission >schizogony >mitosis
mitosis
Consider the process by which bacterial populations grow. What process performs a similar function in humans? >transformation >binary fission >meiosis >mitosis
mitosis
What grows from centrosomes?
mitotic spindle
During meiosis, homologous chromosomes sometimes "stick together" and do not separate properly. This phenomenon is known as _____. >gametic infertility >meiotic failure >nondisjunction >sticky chiasmata
nondisjunction
The kinetochores are _____. >the primary centromere structures that maintain the attachment of the sister chromatids prior to mitosis >located at the center of the centrosome; their function is to organize tubulin into elongated bundles called spindle fibers >sites at which microtubules attach to chromosomes >found as each spindle interlocks at the cell's equator and then moves apart, causing the cell to elongate
sites at which microtubules attach to chromosomes
An example of a cell that is 2n is a _____. >somatic cell >gametophyte >sperm or ovum >haploid cell
somatic cell
DNA replication occurs in _____. >the S phase of interphase >prophase of both mitosis and meiosis >the G1 phase of interphase in reproductive cells only >metaphase of meiosis only
the S phase of interphase
Define nondisjunction
the failure of chromosome pair separating properly
During _____ both the contents of the nucleus and the cytoplasm are divided. >mitosis >G2 >the mitotic phase >G1 >S
the mitotic phase
During mitosis, the chromosomes move because _____. >they diffuse within the nucleus to areas where they are less concentrated >of the duplication of the centrosome >they attach to a dynamic, precisely regulated mitotic spindle >they slide along microfilament bundles
they attach to a dynamic, precisely regulated mitotic spindle
Individual chromosomes are usually observed with a light microscope during mitosis, even though cells spend more time in interphase. This is because _____. >they have uncoiled to form long, thin strands >sister chromatids do not pair up until division starts >they leave the nucleus and are dispersed to other parts of the cell >the DNA has not been replicated yet
they have uncoiled to form long, thin strands
True or False: Sexual reproduction creates genetic diversity
true
Mitosis and cytokinesis result in the formation of _____; meiosis and cytokinesis result in the formation of _____. >two diploid cells ... four haploid cells >two diploid cells ... two haploid cells >two diploid cells ... two diploid cells >four diploid cells ... four haploid cells
two diploid cells ... four haploid cells
