Mastering 12 (Chapter 8)

The sister chromatids separate and begin moving toward opposite poles of the cell during which phase of mitosis? Prophase Anaphase Interphase Metaphase Telophase

Anaphase

How is the aging process linked to telomeres? When telomeres get too long, a signal is sent to the gene to stop the production of all proteins. Cells with short telomeres can no longer divide, so damaged tissues cannot be repaired. There is only a link between the aging process and telomeres in naked mole rats - but not in humans. When a person ages, they begin to get larger and larger telomeres.

Cells with short telomeres can no longer divide, so damaged tissues cannot be repaired.

Which of the following most accurately describes Katie's situation? Katie was born with both male and female external genitalia. Katie grew up with a gender identity of being a girl because that's how she was treated from birth. Katie was born with testes, but her cells did not respond to the testosterone those testes produced. Since being intersex is often caused by a genetic mutation, both of Katie's parents must have been intersex as well.

Katie was born with testes, but her cells did not respond to the testosterone those testes produced.

What is the function of cell division? to enable a multicellular organism to grow to adult size to replace worn out or damaged cells to produce gametes for sexual reproduction all of the above

all of the above

Many enzymes are named for the substrate on which they work, either to build or disassemble molecules. Also, enzyme names often end in "-ase." For example, lactase is the enzyme that breaks down lactose. With a name like "telomerase," we can deduce that telomerase is probably: an enzyme that regulates the assembly of DNA at the ends of chromosomes a protein that tells the cell when to divide and produce new cells an enzyme that chains sugars together to make starches, to provide food for the cell some type of a nucleotide that codes for protein, perhaps DNA or RNA

an enzyme that regulates the assembly of DNA at the ends of chromosomes

During cell division, the DNA is in a coiled up and compacted form called ___. When the cell is not dividing, the DNA is in long thin fibers called ___. ribosomes, chromosomes genes, centromeres centromeres, sister chromatids chromatin, chromosomes chromosomes, chromatin

chromosomes, chromatin

At the end of the mitotic (M) phase, the cytoplasm divides in a process called _________________. cytokinesis telophase condensation replication meiosis

cytokinesis

There are nearly 30 different disorders of sexual development. Who can have these disorders? people with neither XX nor XY chromosomes only people with XY chromosomes people with either XX or XY chromosomes only people with XX chromosomes

people with either XX or XY chromosomes

Meiosis is the process that: skin uses to repair itself produces identical daughter cells the ovaries use to produce diploid eggs produces diploid gametes in haploid organisms produces haploid gametes in diploid organisms

produces haploid gametes in diploid organisms

The correct order of events during meiosis is prophase I, metaphase I, anaphase I, telophase I, cytokinesis, meiosis II. prophase I, anaphase I, metaphase I, telophase I, meiosis II, cytokinesis. metaphase I, prophase I, telophase I, anaphase I, cytokinesis, meiosis II. prophase I, anaphase I, telophase I, metaphase I, meiosis II. metaphase I, prophase I, anaphase I, telophase I, cytokinesis, meiosis II.

prophase I, metaphase I, anaphase I, telophase I, cytokinesis, meiosis II.

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? Metaphase I. anaphase I. prophase I. meiosis II. telophase I.

prophase I.

Gametes: are diploid contain twice the number of chromosomes as the parent cell in humans contain 23 chromosomes in humans contain 46 chromosomes are the result of mitosis

in humans contain 23 chromosomes

Gametes are produced by _____. meiosis mitosis fertilization the cell cycle asexual reproduction

meiosis

Genetic variation is NOT increased by: independent assortment of chromosomes crossing over random fertilization mitosis

mitosis

The failure of a chromosome pair to separate during meiosis is called: karyotyping mitosis nondisjunction homologous chromosomes

nondisjunction

What are telomeres? protein caps found on the ends of chromosomes DNA sequences which code for making proteins that regulate cell division regions of DNA at the end of chromosomes which do not code for making proteins "junk DNA" present throughout the length of our chromosomes

regions of DNA at the end of chromosomes which do not code for making proteins

How many autosomes do humans have? 23 46 2 22 44

44

How does meiosis differ from mitosis? Cells produced by meiosis are diploid, while cells produced by mitosis are haploid. In meiosis the chromosomes are duplicated twice. In meiosis cytokinesis occurs once, while in mitosis cytokinesis occurs twice. Meiosis is used to repair tissues such as skin. In meiosis four daughter cells are produced, while in mitosis two daughter cells are produced.

In meiosis four daughter cells are produced, while in mitosis two daughter cells are produced.

The centrosomes move away from each other and the nuclear envelope breaks up during which phase of mitosis? Interphase Telophase Prophase Metaphase Anaphase

Prophase

A cell preparing to undergo meiosis duplicates its chromosomes during prophase I. interphase. anaphase I. metaphase I. meiosis II.

interphase

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

16

Normal human gametes carry _____ chromosomes. 23 46 46 pairs of 23 pairs of 5

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? 48 24 12 6

24

Which of the following checkpoints does not occur late in G1? 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 A check that growth factors are present

A check that chromosome replication has been successfully completed

Crossing over of chromosomes during meiosis shuffles parental chromosomes, resulting in a genetically unique child. Select the three true statements about crossing over. Chromosomes from the egg and the sperm undergo crossing over immediately after fertilization occurs. During prophase I of meiosis I, homologous paternal and maternal chromosomes line up at the metaphase plate. During meiosis II, sister chromatids separate into four different gametes. A hybrid chromosome that has crossed over will contain pieces of both the maternal and paternal chromosomes. Chiasmata in nonsister chromatids decrease the genetic variability produced during crossing over.

A hybrid chromosome that has crossed over will contain pieces of both the maternal and paternal chromosomes. During prophase I of meiosis I, homologous paternal and maternal chromosomes line up at the metaphase plate. During meiosis II, sister chromatids separate into four different gametes.

___________ reproduction is a means of creating new individuals solely by ___________ , the form of cell division that creates genetically identical daughter cells.

Asexual, Mitosis

Many people with XY chromosomes and androgen insensitivity syndrome (AIS), like Katie, are not diagnosed until later in life, rather than at birth. Why is that? People with XY chromosomes and AIS can get pregnant, but often have a miscarriage. The frequent miscarriages cause doctors to investigate further. Babies with XY chromosomes and AIS usually appear to be normal females at birth. It is not until they have a hernia, or fail to menstruate, before a doctor would investigate further. People with XY chromosomes and AIS have ovaries that do not develop until later in life. Babies with XY chromosomes and AIS are born with one set of external genitals, but their genitals change to appear like that of the other sex later in life. This change causes doctors to investigate further.

Babies with XY chromosomes and AIS usually appear to be normal females at birth. It is not until they have a hernia, or fail to menstruate, before a doctor would investigate further.

Which of these cells is (are) haploid? There is a cell in interphase labeled A. A cell labeled B is ready for meiosis with necessary changes occurred. Cells after meiosis 1 are labeled C. Cells after meiosis 2 are labeled D. B A and D B and C D C and D

C and D

Which of the following biologically describes a hermaphrodite? A human baby is born with XX chromosomes, but has a very large clitoris that resembles a penis. Earthworms can fertilize each other to produce offspring. Pistachio trees have female flowers on one plant, and male flowers on another plant. A human baby is born with XY chromosomes, but lacks a penis and has a vagina.

Earthworms can fertilize each other to produce offspring.

True or false. Mitosis takes place during M phase of the cell cycle, which is longer than interphase. True False

False

How does the karyotype of a human female differ from the karyotype of a human male? Females have two X chromosomes, and males have X and Y chromosomes. Females have sex chromosomes, and males have only autosomes. Females have only autosomes, and males have sex chromosomes. Females have X and Y chromosomes, and males have two X chromosomes. There is no difference in the karyotype between males and females.

Females have two X chromosomes, and males have X and Y chromosomes.

Which of the following has the greatest potential as a cancer treatment? Find a way to turn off the gene for making telomerase in all cells in embryos, so that they never develop cancer. Find a way to turn on the gene for making telomerase in normal cells, so that the normal cells would soon outnumber the cancer cells. Find a way to turn on the gene for making telomerase in cancer cells, since they will be unable to divide if their telomeres are too long. Find a way to turn off the gene for making telomerase in cancer cells, since the cells would stop dividing when the telomeres were gone.

Find a way to turn off the gene for making telomerase in cancer cells, since the cells would stop dividing when the telomeres were gone.

Gender identity is a person's personal sense of being a man or a woman. Katie says at the end of the clip that, given the traditional definitions of sex, she can't say whether her sex is male or female, but that her gender identity is definitely that of a woman. What does this indicate about gender identity? Gender identity is mostly dependent on external genitalia. Gender identity is mostly dependent on internal reproductive organs. Gender identity is mostly dependent on sex chromosomes. Gender identity is mostly likely the result of a combination of physical, physiological, and social factors.

Gender identity is mostly likely the result of a combination of physical, physiological, and social factors.

Which of the following statements is true? Meiosis leads to two daughter cells that are genetically identical to each other. Meiosis is sometimes called reduction division. Meiosis is asexual cellular reproduction, while mitosis creates gametes for sexual reproduction. Mitosis results in the formation of four daughter cells, where each daughter cell has only one chromosome from each homologous pair.

Meiosis is sometimes called reduction division.

The chromosomes line up in the center of the cell during which phase of mitosis? Anaphase Interphase Metaphase Telophase Prophase

Metaphase

Which of the following problems during DNA replication is being illustrated with the kids in the video? DNA replication is a very random process, and many mistakes are made. Within a chromosome, there is more telomerase than there is DNA. DNA replication only occurs in cancer cells. Nucleotides at the ends of the DNA strands are lost when DNA replicates.

Nucleotides at the ends of the DNA strands are lost when DNA replicates.

Which of the following describes how we inherit our chromosomes? We receive our autosomes from our mother, and our sex chromosomes from our father. We receive our sister chromatids only from our father . We receive our sister chromatids only from our mother. We receive our autosomes from our father, and our sex chromosomes from our mother. One of each of the homologous chromosomes comes from our father, and the other of each of the homologous chromosomes comes from our mother.

One of each of the homologous chromosomes comes from our father, and the other of each of the homologous chromosomes comes from our mother.

___________ reproduction, in contrast, generates genetically unique offspring. To accomplish this, an organism must produce ___________-- sperm and egg -- through the process of ___________. The cells produced this way will be ________, meaning that they contain a single set of chromosomes. Such cells are produced only in the ________.

Sexual, Gametes, Meiosis, Haploid, Gonad

Which of the following is the best option if Katie wants to have children? She can take high doses of estrogen in order to maintain a pregnancy in her uterus. She can adopt children. She can have eggs removed from her ovaries for later in-vitro fertilization and implantation. She can have surgery to modify her external genitalia.

She can adopt children.

In the video, the narrator says that Katie had her testes removed, and now takes pills to give her more appropriate hormones. What is the most likely explanation? Since Katie has no ovaries to produce estrogen, she likely takes an estrogen supplement that supports her gender identity. Without hormone supplements, her body could develop male genitalia. Without hormone supplements, she will be unable to get pregnant. Since Katie is no longer producing testosterone, she must take a testosterone supplement to stay healthy.

Since Katie has no ovaries to produce estrogen, she likely takes an estrogen supplement that supports her gender identity.

The chromosomes arrive at the poles and nuclear envelopes form during which phase of mitosis? Anaphase Interphase Metaphase Prophase Telophase

Telephase

Which cells are most likely to have the gene for making telomerase switched on? The skin cells of a 28 year old person. The muscle cells of a woman who is 80 years old. The cells in a developing embryo. The nerve cells of a 55 year old man.

The cells in a developing embryo.

What must happen before a cell can begin mitosis? The nucleus must divide in two. The chromosomes must be duplicated. The nuclear envelope must break up. The sister chromatids must be separated. A mitotic spindle must form.

The chromosomes must be duplicated.

Which of the following is NOT true about naked mole rats? They seem to be resistant to getting cancer. Their cells do not produce telomerase. They can survive in burrows with high levels of carbon dioxide. They often live for 30 years.

Their cells do not produce telomerase.

The 23rd pair of chromosomes in human females is ___, and the 23rd pair of chromosomes in human males is ___. XY, XX X, Y Y, X XY, XY XX, XY

XX, XY

An orderly picture of magnified images of stained chromosomes is called: a chiasma a gamete an autosome a karyotype a centromere

a karyotype

A karyotype would be helpful in diagnosing or determining: Klinefelter syndrome, due to an extra X chromosome Turner syndrome, due to a missing sex chromosome Down syndrome, due to an extra chromosome 21 the sex of a person all of the above

all of the above

Except for the sex chromosomes, the members of a homologous pair of chromosomes: are the same size are the same shape have the same gene content all of the above

all of the above

What name is given to this process? A cycle consisting of 3 steps. In the lower left is a single hydra, labeled 1. At the top is the single hydra with a small hydra budding off of it, labeled 2. In the lower right are two individual hydra, labeled 3. The cycle continues back to step 1. sexual reproduction gametogenesis asexual reproduction meiosis fertilization

asexual reproduction

Homologous chromosomes: all come from the same parent are the same thing as sister chromatids are exactly identical carry the same genes in the same places

carry the same genes in the same places

Meiosis starts with a single diploid cell and produces four diploid cells. eight haploid cells. two diploid cells. two haploid cells. four haploid cells.

four haploid cells.

During prophase I of meiosis, 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 two daughter cells, each with 23 chromosomes. there are four haploid daughter cells.

homologous chromosomes stick together in pairs.

Rank from the first event to the last event, left to right. 1. homologous chromosomes pair up 2. nonsister chromatids form chiasmata 3. crossing over occurs 4. homologous chromosomes separate 5. sister chromatids separate 6. four haploid gametes are produced

they are in order