MODULE 5 bio updated

Following meiosis I, the daughter cells are ______; following meiosis II, the daughter cells are ______; and following mitosis, the daughter cells are _______.

haploid; haploid; diploid

Following meiosis I, the daughter cells are ________; following meiosis II, the daughter cells are ________; and following mitosis, the daughter cells are ________.

haploid; haploid; diploid

Chromosomes that occur in pairs and code for the same traits are called ________ chromosomes; these do not include the ________ chromosomes, which code for gender.

homologous: sex

Metaphase II is more similar to metaphase of mitosis than to metaphase I because

in metaphase II, dyads align separately at the spindle equator.

Multicellular organisms undergo mitotic cell division to

increase the size of the organism

Which of the following processes does not contribute to creating genetic variability in the offspring?

interkinesis

While Jeff was looking under the microscope at cells in different stages of mitosis he commented on the fact that many cells were in the same stage. If you were looking under the compound light microscope at an onion root tip, what stage would the majority of the cells be in the cell cycle?

interphase

While Jeff was looking under the microscope at cells in different stages of mitosis, he commented on the fact that many cells were in the same stage. If you were looking under the compound light microscope at an onion root tip, in what stage of the cell cycle would the majority of the cells be?

interphase

Angiogenesis contributes to carcinogenesis because

it causes blood vessels to grow into the tumor

_______ are a type of internal signal molecule used in controlling the cell cycle

kinases

Klinefelter syndrome can result from nondisjunction during

meiosis I or II in the male parent.

If cells in the process of dividing are subjected to a drug that interferes with the formation of the spindle apparatus, at which stage will mitosis be arrested?

metaphase

The figure below shows a cell in the mitotic stage of

metaphase

Which of the following is a correct match?

separation of sister chromatids - anaphase II

When a portion of a chromosome breaks off and attaches to a different chromosome this is called a

translocation

Which of the following organelles would be abundant and in close proximity to the cell plate in a plant cell undergoing cytokinesis?

Golgi apparatus

Which of the following statements is correct?

Meiosis involves two divisions and produces four nonidentical daughter nuclei.

What is the product of mitosis in plant cells?

Two daughter cells with genetically identical chromosomes/nuclei

Which of the following phases results in separation of sister chromatids into daughter chromosomes?

anaphase II and anaphase of mitosis

(a)State the names of the parts of the chromosome labelled (i) and (ii) on the diagram below.(!!!!)

(i) centromere (ii) sister chromatids

An individual with the karyotype 48, XYYY would have how many Barr bodies?

0

A group of cells is assayed for DNA content immediately following mitosis and is found to have an average of 8 picograms of DNA in the nucleus. Those cells would have ________ picograms at the end of the S phase and ________ picograms at the end of G2.

16;16

During prophase II, a diploid organism contains how many copies of each gene?

2

The failure of sister chromatids to separate would result in how many normal gametes?

2

The diagram below shows a cell during meiosis I. (!!!) How many chromosomes would each daughter cell have at the end of meiosis?

2 - In the diagram there are two pairs of homologous chromosomes (4 total), each of which has two identical sister chromatids. After meiosis, the daughter cells will have half of that so 2 chromosomes.

Armadillos have a diploid chromosome number of 64. At prophase I, an armadillo's cell would have ________ tetrads present.

32

During prophase I, a diploid organism contains how many copies of each gene?

4

In each gamete following telophase II, how many copies of each gene is/are present?

4

A cell with a diploid number of 12 chromosomes undergoes meiosis. What will be the product at the end of meiosis?

4 daughter cells with 6 chromosomes each

Turner syndrome is associated with which of the following karyotypes?

45, XO

Camels have a diploid chromosome number of 70. At prophase II, each cell would contain how many chromatids?

70

Draw diagrams to show the four stages of mitosis in an animal cell with four chromosomes. **Need to be able to draw and label chromosomes, centrosomes, microtubules and nuclear envelope for prophase, metaphase, anaphase and telophase

??????

(b)Identify the parts of the cell cycle labelled A and B. (!!!)

A - Interphase B - mitosis/cytokinesis

Colchicine is a chemical substance that prevents the formation of microtubules. What stage of mitosis would be prevented, if dividing cells were treated with colchicine? (describe what normally happens during this stage)

Anaphase ...which would prevent the separation of genetically identical chromosomes (sister chromatids)

You are looking at a cell under a microscope and see what appears to be several "X" structures being pulled to each side of the cell. What stage of meiosis are you looking at?

Anaphase I

The diagram below shows a cell undergoing meiosis.(!!!) What is this stage of meiosis?

Anaphase I because homologous chromosomes are separating

Cells grown in a petri dish tend to divide until they form a thin layer covering the bottom of the dish. Which of the following statements explains why this occurs?

Cell division can be inhibited by the proximity of other cells of the same type, a process called contact inhibition.

According to cell theory all cells arise from pre-existing cells. This diagram shows the cell cycle of a eukaryotic (body) cell of a diploid organism. (a)Define the term diploid.

Cell with two copies of each chromosome, or pairs of homologous chromosomes.

Which processes always occur in meiosis but not normally in mitosis?

Chiasmata formation Exchange of genetic material between homologous chromosomes Separation of homologous chromosomes

The diagram below shows chromosomes during prophase I of meiosis. (!!!) How many individual chromosomes (sister chromatids) and chiasmata are visible?

Chromosomes - I would accept 2 or 4 (2 pairs of sister chromatids, or 4 total chromosomes) Chiasmata - 2

Which of the following statements is true?

Chromosomes are classified into two categories: the sex chromosomes that determine gender and autosomes that determine non-gender related traits.

Describe, with the aid of a diagram, the behavior of chromosomes in the different phases of meiosis.

Chromosomes condense during prophase I and join together with their homologous chromosomes, forming tetrads. Crossing over also takes place between homologous chromosomes during prophase I. During metaphase I, the homologous chromosomes line up in a random order in the middle of the cell, and they will separate during anaphase I. In telophase I a nuclear envelope forms around the separated homologous chromosomes. In prophase II, the nuclear envelope breaks down and the microtubules attach to the sister chromatids. The sister chromatids line up in the middle of the cell during metaphase II and are separated during anaphase II. In telophase II, a nuclear envelope forms around the separated sister chromatids and each daughter cell now has half of the chromosomes as the parent cell.

Which of the following is not correct about crossing-over?

Crossing over is only detectable when it occurs between sister chromatids.

Susan was examining a cell under the microscope and noticed the formation of a cell plate in the midline of the cell and the formation of nuclei at opposite poles of the cell. The cell under examination was most likely a(n)

Cytokinesis is the division of the cytoplasm following mitosis that produces two daughter cells. A cell plate is characteristic of a plant cell in cytokinesis.

The G2 check point prevents the cell cycle from continuing until

DNA is completely replicated AND damage to DNA can be repaired

Interphase differs from interkinesis because

DNA is duplicated during interphase, but not during interkinesis.

All of the following occur during the latter stages of mitotic prophase except the

DNA replication occurs during interphase, not during prophase.

Describe the behavior of chromosomes in metaphase I and anaphase II of meiosis?

During metaphase I, homologous chromosomes line up at the equator of the cell and microtubules attach to them. During Anaphase II, the sister chromatids are separated and move towards opposite sides of the cell.

Rebecca found out that she has a mass of dividing cells called a tumor in her ovaries. She has had tests and is returning to the doctor. Which of the following would be the best news that Rebecca could receive from her doctor?

During metastasis, a malignant tumor invades neighboring tissues and spreads through the body, while a benign tumor does not invade neighboring tissue.

What is occurring in the cell cycle during interphase?

G1 - cell grows and makes proteins S - DNA replication G2 - cell grows and prepare for division

(c)State three activities that occur during part A of the cell cycle.

G1 - cell grows and synthesizes proteins. S - DNA replication occurs. G2 - Cell grows and prepares for cell division

Which of the following organelles would be abundant and in close proximity to the cell plate in a plant cell undergoing cytokinesis

Golgi apparatus

Which event occurs first in meiosis?

Homologous chromosomes join together

Which phases of mitosis are shown in diagrams I and II? (!!!)

I - metaphase II - prophase

During meiosis II,

In meiosis II, the arrangement of chromosomes during metaphase resembles that of mitosis, with chromosomes aligned separately at the metaphase plate, and each sister chromatid facing the opposite spindle pole.

Which of the following statements is correct regarding the events of the cell cycle

Interphase consists of G1, S, and G2.

Riley found out that she has a mass of dividing cells called a tumor in her ovaries. She has had tests and is returning to the doctor. What would the best results the doctor could tell her be?

It is a benign tumor

Which of the following is not a function of meiosis?

Meiosis produces gametes and creates genetic variability, but it is not used to increase cell numbers of an organism.

During which stage of meiosis will the pairs of homologous chromosomes line up?

Metaphase I

The mitotic spindle is composed of______and grows from the_____toward the center of the cell

Microtubles; centrosome

(c)Compare and contrast mitosis and meiosis

Mitosis vs. Meiosis 1 cell division vs. 2 cell division 2 diploid daughter cells vs. 4 haploid daughter cells Same number of chromosomes vs. half the number of chromosomes Produces somatic cells for growth/repair vs. Produces gametes for sexual reproduction

Multicellular organisms undergo mitotic cell division to

Mitotic cell division creates a new daughter cell that is identical to the parent cell, leading to an increased number of cells in a multicellular organism and allowing it to increase in size.

(b)Explain how the inheritance of chromosome 21 can lead to Down's syndrome.

Non-disjunction occurs and the 21st homologous chromosomes fail to separate in a gamete. Then, during fertilization a gamete with an extra copy of the 21st chromosome will join with another gamete and produce an offspring with 3 copies of the 21st chromosome instead of two. This is called trisomy 21, which causes Down's Syndrome.

Cells that do not receive the correct signals to move from G1 into S phase will enter G0

Not undergo mitotic division unless it later receives the go ahead signal

The new drug chloral hydrate prevents elongation of microtubles by preventing the addition of new subunits to the growing end. During which stage of mitosis would chloral hydrate be most harmful?

Prophase

Which items in the following pairs are correctly matched?

S phase - DNA replication

Refer to the figure below. Differentiated cells, such as nerve cells, would be in which of the following stages of the cell cycle?

Specialized or differentiated cells are in the G0 stage; they will not divide but remain in the G0 phase.

Which of the following is not a symptom of Down syndrome?

Tall stature

A positive genetic test for telomerase indicates that

Telomerase is active in embryonic cells and some stem cells, but not adult cells. Active telomerase in an adult cell may indicate that it has become cancerous.

Inheritance of mutant forms of some genes may lead to a predisposition to develop cancer. Which of the genes listed below has not been linked to hereditary forms of cancer?

The DScam gene acts as a cell identification protein for neurons, and does not affect the cell cycle.

A tumor suppressor gene undergoes a mutation that causes it to lose its normal function what would be the most likely result of this mutation

The cell no longer responds to signals that cause it to stop dividing or undergo apoptosis

A tumor suppressor gene undergoes a mutation that causes it to lose its normal function. What would be the most likely result of this mutation?

The cell no longer responds to signals that cause it to stop dividing or undergo apoptosis.

A mutation results in a cell that no longer produces a normal kinase for the M-phase checkpoint. which of the following would likely be the immediate result of this mutation

The cell would never leave metaphase

What would occur if the production of cyclone halted during the cell cycle

The cell would remain in the G2 phase and would not enter into mitosis

Cells grown in a petri dish tend to divide until they form a thin layer covering the bottom of the dish. If cells are removed from the middle of the dish, the cells bordering the open space will begin dividing until they have filled the empty space. What does this experiment show?

The cells continued to grow as long as there was empty space. When cells come into contact with other cells they would stop growing, or be turned off.

What does a karyotype show?

The number, size, and shape (or appearance) of the chromosomes of an organism

Which statement best describes how the members of a tetrad are separated during meiosis I?

The two homologous chromosomes of a tetrad separate into different daughter nuclei.

If there are 20 centromeres in a cell, how many chromosomes are there?

There is one centromere for every replicated chromosome that holds two sister chromatids together. In other words, two sister chromatids are considered one replicated chromosome. Once sister chromatids separate, they are each considered to be a full-fledged chromosome, which is now unreplicated.

Which statement is characteristic of tumors?

They are an abnormal mass of tissue or cells that result from uncontrolled cell division and occur in any organ

Explain how meiosis results in great genetic variety among gametes

Three processes occur during meiosis that lead to genetic variation among gametes. Crossing Over - occurs during prophase I and is the exchange of genetic information between paternal and maternal chromosomes. This results in recombinant chromosomes that are composed a combination of chromosomes containing genes from the mother and father. Random Orientation - the homologous chromosomes and sister chromatids will line up in a random order and orientation during metaphase I and II, resulting in different chromosomes passing to each gamete. Law of Independent Assortment - the separation of one pair of alleles is independent of the separation of another pair of alleles. So genes that determine different traits are passed down separately of each other. This leads to 2N possible gametes in an individual, which in humans' means there are 223 possible gametes (8,388,608).

What is the usual cause of Down's syndrome?

Trisomy 21, or when an individual has 3 copies of the 21st chromosome instead of 2

Which of the following human syndromes is a monosomy?

Turner syndrome

What are homologous chromosomes?

Two chromosomes with the same set of genes, in the same sequence, sometimes with different alleles, that come from the mother and father of an individual

Cytokinesis usually, but not always, follows mitosis. If a cell completed mitosis but not cytokinesis, the result would be a cell with

a cell with two or more nuclei

Cytokinesis usually, but not always, follows mitosis. If a cell undergoes mitosis and not cytokinesis, this would result in

a cell with two or more nuclei.

Apoptosis occurs when

a damaged cell is programmed to fragment and then is phagocytized.

A woman inherits a mutant BRCA1 allele from her mother. She has an increased risk of developing breast cancer because

a mutation in her normal BRCA1 allele may lead to cancer, whereas a normal individual would have to acquire two mutations (one in each allele) to develop cancer.

A human egg with 22 chromosomes that is fertilized by a normal sperm will result in

a zygote with monosomy.

An individual with Swyer syndrome (46, XY) differs from an individual with Klinefelter syndrome (47, XXY) because

an individual with Klinefelter syndrome has a functional SRY gene on his Y chromosome, whereas an individual with Swyer syndrome does not.

apoptosis

can be used to remove damaged or malfunctioning cells

Which of the following is not a function of meiosis?

cause an organism to grow

Which of the diagrams best illustrates the appearance of a chromosome or chromosome pair at the end of prophase I?

diagram 2

The looping of DNA around histone proteins

compacts the DNA allowing a large amount of DNA to fit into the cell.

The looping of DNA around histone proteins

condenses a large amount of DNA so that it can fit into the cell.

One major difference between meiosis I and meiosis II is that

crossing over occurs in prophase of meiosis I but not in prophase of meiosis II.

Proteins that are involved in the regulation of the cell cycle, and that show fluctuations in concentration during the cell cycle, are called

cyclins

All but which one of the following results from nondisjunction?

diploidy

A translocation may lead to cancer if it

disrupts control of expression of genes that regulate the cell cycle.

a cell inhibited during the S phase of its cycle. It will not reproduce due to lack of

dna synthesis

When during the cell cycle are chromosomes visible?

during mitosis

Which of the following is not a characteristic of cancer cells

exhibit contact inhibition

Which of the following is not a characteristic of cancer cells?

exhibit contact inhibition

During meiosis I, the homologous chromosomes of a tetrad

face opposite spindle poles.

Which of the following lists is in the correct order, from the least inclusive to the most inclusive?

gene - allele - chromosome

During crossing-over,

genetic material is exchanged between nonsister chromatids, resulting in new combinations of alleles.

The failure of sister chromatids to separate during meiosis is called

nondisjunction

Swyer syndrome (46, XY, female appearance), would most likely result from

normal disjunction during meiosis, but deletion of a portion of the Y chromosome in the male parent.

Cells that do not receive the correct signals to move from G1 into S phase will enter G0 and therefore will

not undergo mitotic division unless it later receives the go-ahead signal.

DNA and histones form bead-like globules known as

nucleosomes

DNA and histones form beadlike globules known as

nucleosomes

Which of the following processes and products are paired correctly?

oogenesis - 1n gamete

Susan was examining a cell under the microscope and noticed the formation of a cell plate in the midline of the cell and the formation of nuclei at opposite poles of the cell. The cell under examination was most likely a(n)

plant cell undergoing cytokinesis

plant cells and animal cells differ in cytokinesis because

plant cells need to build a cell wall while animal do not

Some of the drugs used in chemotherapy work by

preventing spindle formation

Unicellular organisms undergo mitotic division to

produce new organisms

The drug chloral hydrate prevents elongation of microtubules by preventing the addition of new subunits to the growing end. During which stage of mitosis would chloral hydrate be most harmful?

prophase

Cancer is a disorder in which some cells have lost the ability to control their

rate of cell division

structure labeled "d" in the following figure are called

sister chromatids

Crossing-over between sister chromatids does not result in recombination of genetic material, while crossing-over between nonsister chromatids does because

sister chromatids have the same genes, while nonsister chromatids have different ones.

The term metastasis refers to the fact that cancer cells tend to

spread

A proto-oncogene differs from a tumor suppressor gene because a proto-oncogene

stimulates mitosis in a normal cel, whereas a tumor suppressor gene inhibits mitosis

A proto-oncogene differs from a tumor suppressor gene because a proto-oncogene

stimulates mitosis in a normal cell, whereas a tumor suppressor gene inhibits mitosis.

Ben was looking at onion root tip cells under the microscope in biology class. He saw one cell that had two nuclei within it. What stage of the cell cycle was this cell in?

telophase/cytokinesis

It is essential that germ cells undergo meiosis so that

the number of chromosomes is cut in half in gametes.

Cancer occurs when

the regulation of the cell cycle is lost and uncontrolled cell division occurs.

cancer occurs when

the regulation of the cell cycle is lost and uncontrolled cell division occurs.

The spindle serves two rolls in mitotic cell division. These are

to separate the sister chromatids and to elongate the cell.

The term metastasis refers to the fact that cancer cells tend to

travel

A protein that promotes apoptosis would be considered a(n)

tumor suppressor

A tetrad is composed of

two chromosomes with two sister chromatids each.