Biology Honors Ch. 8

does not metastasize.

A benign tumor differs from a malignant tumor in that a benign tumor •does not metastasize. •never causes health problems. •spreads from the original site. •is cancerous.

24

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? •6 •24 •48 •12

a bride and groom.

A pair of sex chromosomes found in a human male is most like •a pair of blue jeans. •identical twins. •a bride and groom. •a knife, fork, and spoon.

somatic cell

An example of a cell that is 2n is a __________. •somatic cell •gametophyte •sperm or ovum •haploid cell

•anaphase

Centromeres divide and sister chromatids become full-fledged chromosomes during _____. •telophase •anaphase •prometaphase •metaphase •interphase

•prophase

Chromosomes become visible during _____. •interphase •metaphase •prometaphase •prophase •anaphase

•telophase

Cytokinesis often, but not always, accompanies _____. •metaphase •anaphase •telophase •prometaphase •interphase

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

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

They organize the microtubules.

During cell division, what role do centrosomes play? •They are the structures that hold the two sister chromatids together. •They organize the microtubules. •They are required for DNA replication. •They cause cytokinesis via the concentric shortening of microtubules

they attach to a dynamic, precisely regulated mitotic spindle

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

two chromosomes and four chromatids

During prophase a homologous pair of chromosomes consists of _____. •one chromosome and four chromatids •four chromosomes and two chromatids •one chromosome and two chromatids •two chromosomes and two chromatids •two chromosomes and four chromatids

•telophase

During which phase of mitosis does the nuclear envelope re-form? •anaphase •metaphase •telophase •prophase

39

When observing a chicken skin cell in G2 under a microscope, you count 156 total chromatids. How many chromosomes does a male chicken have in its sperm cells? •39 •156 •312 •78

sites at which microtubules attach to chromosomes

The kinetochores are __________. •used to organize tubulin into elongated bundles called spindle fibers •the primary centromere structures that maintain the attachment of the sister chromatids prior to mitosis •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

its cells each have one set of chromosomes

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

mutations in the proto-oncogenes

i.e. foot is stuck on the gas pedal; the cell cycle continues faster and faster w/out stopping

heterochromatin

interphase chromosomes in highly condensed areas; DNA that is silent

euchromatin

interphase chromosomes in less compacted areas; DNA that is expressed

tumor

mass of cells formed after a cell repeatedly divides due to problems in the cell cycle

G1 checkpoint

most important of all checkpoints; checkpoint where the cell is checked to make sure it is working correctly

centromere

narrow "waist" of the duplicated chromosome, where the two chromatids are most closely attached

G0 phase

period where the cell does not divide and never leaves interphase

histones

proteins responsible for the 1st level of DNA packing in chromatin

cell division

reproduction of a cell through duplication of the genome and division of the cytoplasm

motor proteins

"walk" along spindle fibers after the chromosomes split; how chromosomes get to opposite poles

3 Stages of Binary Fission

1. duplication of the chromosome and separation of the copies 2. continued elongation of the cell and movement of the copies 3. division into 2 daughter cells

If DNA had not copied correctly at the G2 checkpoint....

1. the cell can stop and try to fix the error 2. stop and send cell to G0 3. apoptosis

interphase

1st part of the eukaryotic cell cycle; period of cell growth and preparation of cell division

S phase

2nd part of interphase; "synthesis"; the chromosomes are doubled and the cell continues to grow

mitosis

2nd part of the eukaryotic cell cycle; process with a series of stages that results in cell division

G2 phase

3rd part of interphase; "second growth"; the cell prepares for mitosis by synthesizing RNA and other proteins

purpose of the kinetochore

to attach the chromosomes to the spindle fiber

purpose of the motor proteins

to walk the chromosomes to the opposite sides of the cell

Binary fission

type of asexual reproduction in which a parent organism divides into 2 genetically identical cells

cancer

uncontrolled cell growth and reproduction; occurs when checkpoint controls are damaged and allows a cell to form a tumor

metastasis

where a tumor grows and interferes w/ a surrounding tissue or cells

cell cycle arrest

where the checkpoint controls halt the cell cycle if any error occurs in the cell cycle

telophase

•chromatids arrive at opposite poles of the cell •new membranes are formed around daughter nuclei •spindle fibers join the cytoskeleton

Regulatory proteins involved in cell cycle control

•cyclins •cyclin-dependent kinases (CdKs)

prokaryotic chromosomes

•have only 1 chromosome •circular DNA molecule •much smaller than those of eukaryotic chromosomes

prophase

•nuclear membrane breaks apart •chromatin condenses • mitotic spindle begins to form •centrioles begin to move to opposite ends of the cell

asexual reproduction

•produces offspring identical to the parent •involves 1 parent

sexual reproduction

•produces offspring that are similar to the parents but w/ variations •involves 2 parents

Stages of Mitosis

•prophase •metaphase •anaphase •telophase

mutations in the tumor suppressor genes

i.e. brakes are broken; no way to stop, uncontrollable cell division

22

How many pairs of autosomes do humans have? •2 •23 •1 •22

92

Imagine that a human skin cell went through mitosis but did not undergo cytokinesis. How many chromosomes would be in the cell? •23 •69 •46 •92

•prophase

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

are permanently in a state of nondivision

Mature human nerve cells and muscle cells •continue to divide throughout their lifetime. •are permanently in a state of nondivision. •become cancerous more easily than other cell types. •cease dividing after a predetermined number of cell generations.

two diploid cells

Mitosis and cytokinesis result in the formation of __________

•interphase

Nucleoli are present during _____. •interphase •prophase •anaphase •prometaphase •metaphase

A check that chromosome replication has been successfully completed

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

prophase, prometaphase, metaphase, anaphase, telophase

Which of the following shows mitosis in the correct chronological order? •anaphase, prometaphase, metaphase, prophase, telophase •telophase, prophase, anaphase, prometaphase, metaphase •prophase, prometaphase, metaphase, anaphase, telophase •prometaphase, metaphase, prophase, telophase, anaphase

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

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

The cell cycle control system operates independently of the growth factors.

Which of the following statements regarding the cell cycle control system is false? •The cell cycle control system operates independently of the growth factors. •The cell cycle control system receives messages from outside the cell that influence cell division. •The cell cycle control system includes three key checkpoints to complete a cell cycle. •The cell cycle control system triggers and controls major events in the cell cycle.

Crossing over is a phenomenon that creates genetic diversity during mitosis.

Which of the following statements regarding the differences between mitosis and meiosis is false? •Cells produced by mitosis are diploid, whereas cells produced by meiosis are haploid. •Crossing over is a phenomenon that creates genetic diversity during mitosis. •In meiosis four daughter cells are produced, whereas in mitosis two daughter cells are produced. •In mitosis cytokinesis occurs once, whereas in meiosis cytokinesis occurs twice.

Mitosis allows organisms to generate genetic diversity.

Which of the following statements regarding the function of mitosis is false? •Mitosis allows organisms to grow. •Mitosis allows organisms to repair tissues. •Mitosis allows organisms to generate genetic diversity. •Mitosis allows organisms to reproduce asexually.

The sequences are identical.

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 unrelated. •The sequence in one chromatid is complementary to the sequence in the other. •The sequences are identical. •The sequences are similar, but not identical.

cell division (detailed)

____________________ is used for ▫ reproduction of single-celled organisms ▫ growth of multicellular organisms (1 cell to many cells) ▫ repair and replacement of cells ▫ production of sperm and eggs

nucleosome

basic unit of DNA packing

apoptosis

cell suicide

genome

cell's copy of its DNA

M checkpoint

check to make sure every chromosome split completely

G2 checkpoint

checkpoint to see if the DNA is copied correctly and if there are two centrioles

metaphase

chromosomes line up in the middle of the cell

anaphase

chromosomes split apart and move to opposite sides of the cell

chromatin

complex of DNA and protein that condenses during cell division

cytokinesis

cytoplasm is split; process by which the cytoplasm of a eukaryotic cell divides to produce two cells

G1 phase

first part of interphase; "first growth"; the cell performs basic function, grows, and synthesizes RNA

Mitosis Promoting factor (MPF)

formed when cyclins and CdKs have high levels of proteins and bond

chromosome

gene-carrying structure found in the nucleus of a eukaryotic cell; contains most of the cell's DNA

proto-oncogenes

genes that tell the cell cycle to proceed

tumor suppressor genes

genes that tell the cell cycle to stop when the cell finished dividing and no more are needed