Bio Chp 8

A human bone marrow cell in the prophase stage of mitosis contains 46 chromosomes. Therefore, there are a total of __________ sister chromatids in this cell. 1. 23 or 46, depending on whether you look at the beginning or end of prophase 2. 46 3. 23 4. 92

92

Which of the following checkpoints does not occur late in G1? 1.A check that growth factors are present 2.A check that the cell is large enough for division 3.A check that chromosome replication has been successfully completed 4.A check that nutrients are sufficient

A check that chromosome replication has been successfully completed

Which of the following statements regarding cell division is false? 1.Cell division is necessary for development to occur. 2.Cell division can reproduce an entire organism. 3.Cell division is the basis of both sexual and asexual reproduction. 4.Cell division is common in eukaryotes but rare in prokaryotes.

Cell division is common in eukaryotes but rare in prokaryotes.

The first step of bacterial replication is _____. 1.separation of daughter cells 2.attachment of the DNA to the plasma membrane 3.DNA replication 4.pinching of the plasma membrane

DNA replication

Within one chromosome, what is the relationship between the sequence of bases in DNA of one sister chromatid compared to the other? 1.The sequences are identical. 2.The sequences are unrelated. 3.The sequence in one chromatid is complementary to the sequence in the other. 4.The sequences are similar, but not identical.

The sequences are identical.

During _____ the cell grows and replicates both its organelles and its chromosomes. 1.mitosis 2.S 3.G1 4.interphase 5.cytokinesis

interphase

Eukaryotic cells spend most of their cell cycle in which phase? 1.metaphase 2.telophase 3.prophase 4.interphase

interphase

When we say that an organism is haploid, we mean that _____. 1.its cells each have one chromosome 2.its cells each have one set of chromosomes 3.Its cells have one half of a chromosome 4.its cells each have two sets of chromosomes

its cells each have one set of chromosomes

Sister chromatids are 1.made only of DNA. 2.joined together at a centromere. 3.unique to prokaryotes. 4.found right after a cell divides.

joined together at a centromere.

In some organisms such as certain fungi and algae, cells undergo mitosis repeatedly without subsequently undergoing cytokinesis. What would be the consequence of this? 1.large cells containing many nuclei 2.a decrease in chromosome number 3.division of the organism into many cells, most lacking nuclei 4.an inability to duplicate DNA

large cells containing many nuclei

Gametes are produced by _____. 1.meiosis 2.asexual reproduction 3.fertilization 4.the cell cycle 5.mitosis

meiosis

Variation occurs when chromosomes are shuffled in _____. 1.meiosis 2.genetic drift 3.mutation 4.mitosis

meiosis

During which phase of mitosis do the chromosomes line up on a plane equidistant from the two spindle poles? 1.prophase 2.telophase 3.anaphase 4.metaphase

metaphase

After fertilization, the resulting zygote begins to divide by __________. 1.schizogony 2.mitosis 3.meiosis 4.binary fission

mitosis

Down syndrome can be the result of _____. 1.deletion of chromosome 21 2.a deletion in chromosome 22 3.occurrence of meiosis without cytokinesis 4.nondisjunction of chromosome 21 during meiosis

nondisjunction of chromosome 21 during meiosis

Crossing over occurs during _____. 1.prophase I 2.prophase II 3.metaphase I 4.anaphase I

prophase I

Crossing over occurs during _____. 1.prophase II 2.metaphase II 3.metaphase I 4.prophase I

prophase I

A diploid organism whose somatic (nonsex) cells each contain 32 chromosomes produces gametes containing _____ chromosomes. 1. 30 2. 16 3. 64 4. 32 5. 8

16

Normal human gametes carry _____ chromosomes. 1. 46 pairs of 2. 23 pairs of 3. 46 4. 5 5. 23

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? 1. 24 2. 12 3. 48 4. 6

24

In meiosis II, _____. 1.homologous chromosomes pair to ensure their even distribution to daughter cells 2.chromosomes cross over to exchange genetic information 3.chromosome number is reduced from diploid to haploid 4.sister chromatids are separated

sister chromatids are separated

DNA replication occurs in _____. 1.the S phase of interphase 2.prophase of both mitosis and meiosis 3.the G1 phase of interphase in reproductive cells only 4.metaphase of meiosis only

the S phase of interphase

During _____ both the contents of the nucleus and the cytoplasm are divided. 1.the mitotic phase 2.G1 3.G2 4.mitosis 5.S

the mitotic phase

During mitosis, the chromosomes move because _____. 1.they attach to a dynamic, precisely regulated mitotic spindle 2.they slide along microfilament bundles 3.they diffuse within the nucleus to areas where they are less concentrated 4.of the duplication of the centrosome

they attach to a dynamic, precisely regulated mitotic spindle

Mitosis and cytokinesis result in the formation of __________; meiosis and cytokinesis result in the formation of __________. 1.two diploid cells : four haploid cells 2.two diploid cells : two diploid cells 3.two diploid cells : two haploid cells 4.four diploid cells : four haploid cells

two diploid cells : four haploid cells

At the end of telophase I of meiosis, as cytokinesis occurs, there are __________. 1.one haploid ovum and three polar bodies 2.four haploid cells 3.two haploid cells 4.two diploid cells

two haploid cells

Why are individuals with an extra chromosome 21, which causes Down syndrome, more numerous than individuals with an extra chromosome 3 or chromosome 16? 1.Down syndrome results in more serious symptoms than either trisomy 3 or trisomy 16. 2.Nondisjunction of chromosomes 3 and 16 probably occurs more frequently. 3.There are probably more genes on chromosome 21 than on either chromosomes 3 or 16. 4.Extra copies of the other somatic chromosomes are probably fatal.

Extra copies of the other somatic chromosomes are probably fatal.

Immune system cells enter a resting phase after undergoing mitosis. When activated—for example, by an infection—they can reenter the sequence of events in the cell cycle that leads to cell division. What would be the correct cell cycle sequence of events for these reactivated cells? 1.S, G1, G2, M 2.G1, G2, S, M 3.G1, S, G2, M 4.G1, M, G2, S, G1

G1, S, G2, M

During binary fission, each copy of the duplicating chromosome moves to opposite ends of the cell. What does this achieve? 1.It ensures the formation of two complete nuclei around each of the chromosomes. 2.It ensures that each daughter cell receives one copy of the chromosome. 3.This keeps the separate chromosomes together. 4.It causes the cell to elongate.

It ensures that each daughter cell receives one copy of the chromosome.

Which of the following statements regarding mitosis and meiosis is false? 1.All sexual life cycles involve an alternation of diploid and haploid stages. 2.Mitosis produces daughter cells with half the number of chromosomes as the parent cell. 3.Meiosis only occurs in the ovaries and testes. 4.A normal human zygote has 46 chromosomes.

Mitosis produces daughter cells with half the number of chromosomes as the parent cell.

Which of the following statements regarding sexual and asexual reproduction is true? 1.Cell division only occurs after sexual reproduction. 2.Sexual reproduction is more likely to increase genetic variation than is asexual reproduction. 3.Only offspring from asexual reproduction inherit traits from two parents. 4.Sexual reproduction typically includes the development of unfertilized eggs.

Sexual reproduction is more likely to increase genetic variation than is asexual reproduction.

What is different concerning the DNA in bacterial cells as opposed to eukaryotic cells? 1.the amount of DNA present 2.whether the DNA is housed in a nucleus or not 3.whether the DNA is linear or circular 4.all of the above are differences between prokaryotic and eukaryotic DNA

all of the above are differences between prokaryotic and eukaryotic DNA

In many organisms, including humans, chromosomes are found in homologous pairs. Homologous chromosomes _____. 1.have roughly similar arrangements of their genes, but some versions of the genes may differ between the chromosomes 2.are identical in the arrangement of their genes, but some versions of the genes may differ between the chromosomes 3.are similar in size and shape, but this deceptive similarity has nothing to do with placement of gene arrangement or type 4.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

Bacteria divide by: 1.sexual reproduction 2.binary fission 3.meiosis 4.mitosis

binary fission

Which of the following types of organisms commonly demonstrates polyploidy? 1.fish 2.reptiles 3.mammals 4.flowering plants

flowering plants

Which of the following is a feature of plant cell division that distinguishes it from animal cell division? 1.formation of a cleavage furrow 2.production of four (rather than two) new cells per mitotic division 3.formation of a cell plate 4.lack of cytokinesis

formation of a cell plate

During asexual reproduction, yeast cells can produce _____. 1.two non-identical offspring 2.gametes with the same number of chromosomes as the parent cell 3.gametes with only half as many chromosomes as the parent cell 4.genetically identical offspring

genetically identical offspring