bio chapter 10 Mitosis and Cell Reproduction Terms

anaphase

stage of mitosis during which sister chromatids are separated from each other

binary fission

prokaryotic cell division process

cell cycle

ordered series of events involving cell growth and cell division that produces two new daughter cells

cell plate

structure formed during plant cell cytokinesis by Golgi vesicles forming a temporary structure (phragmoplast) and fusing at the metaphase plate; ultimately leads to the formation of cell walls that separate the two daughter cells

cell-cycle checkpoint

mechanism that monitors the preparedness of a eukaryotic cell to advance through the various cell-cycle stages

centriole

rod-like structure constructed of microtubules at the center of each animal cell centrosome

centromere

region at which sister chromatids are bound together; a constricted area in condensed chromosomes

chromatid

single DNA molecule of two strands of duplicated DNA and associated proteins held together at the centromere

cleavage furrow

constriction formed by an actin ring during cytokinesis in animal cells that leads to cytoplasmic division

condensin

proteins that help sister chromatids coil during prophase

cyclin

one of a group of proteins that act in to help regulate the cell cycle by phosphorylating key proteins

cyclin-dependent kinase (Cdk)

one of a group of protein kinases that helps to regulate the cell cycle when bound to cyclin; it functions to phosphorylate other proteins that are either activated or inactivated by phosphorylation

cytokinesis

division of the cytoplasm following mitosis that forms two daughter cells

diploid

cell nucleus or organism containing two sets of chromosomes (2n)

FtsZ

tubulin-like protein component of the prokaryotic cytoskeleton that is important in prokaryotic cytokinesis

G0

phase distinct from the G1 phase of interphase; a cell in G0 is not preparing to divide

G1 phase (also first gap)

centered on cell growth during mitosis

G2phase (also second gap)

third phase of interphase during which the cell undergoes final preparations

gamete

haploid reproductive cell or sex cell (sperm, pollen grain, or egg)

gene

physical and functional unit of heredity

genome

total genetic information of a cell or organism

haploid

cell nucleus or organism containing one set of chromosomes (n)

histone

one of several similar highly conserved, low molecular weight, basic proteins found in the chromatin of all eukaryotic cells; associates with DNA to form nucleosomes

homologous chromosomes

chromosomes of the same morphology with genes in the same location chromosomes

interphase

period of the cell cycle leading up to mitosis; includes G1, S, and G2 phases (the interim period between two consecutive cell divisions)

karyokinesis

mitotic nuclear division

kinetochore

protein structure associated with the centromere of each sister chromatid that attracts and binds spindle microtubules during prometaphase

locus

position of a gene on a chromosome

metaphase

stage of mitosis during which chromosomes are aligned at the center of the cell

metaphase plate

equatorial plane midway between the two poles of a cell where the chromosomes align

mitosis (also karyokinesis)

period of the cell cycle during which the duplicated chromosomes are separated into identical nuclei

mitotic phase

period of the cell cycle during which duplicated chromosomes are distributed into two nuclei and cytoplasmic contents are divided

mitotic spindle

apparatus composed of microtubules that orchestrates the movement of chromosomes during mitosis

nucleosome

subunit of chromatin composed of a short length of DNA wrapped around a core of histone proteins

oncogene

mutated version of a normal gene involved in the positive regulation of the cell cycle

origin (also ORI)

chromosome where replication begins

p21

cell-cycle regulatory protein that inhibits the cell cycle; its levels are controlled by p53

p53

cell-cycle regulatory protein that regulates cell growth and monitors DNA damage; it halts the progression of the cell cycle in cases of DNA damage and may induce apoptosis

prometaphase

stage of mitosis during which the nuclear membrane breaks down and mitotic spindle fibers attach to kinetochores

prophase

stage of mitosis during which chromosomes condense and the mitotic spindle begins to form

proto-oncogene

normal gene that when mutated becomes an oncogene

quiescent

refers to a cell that is performing normal cell functions and has not initiated preparations for cell division

retinoblastoma protein (Rb)

regulatory molecule that exhibits negative effects on the cell cycle by interacting with a transcription factor (E2F)

S phase

second or synthesis stage of interphase during which DNA replication occurs

septum

structure formed in a bacterial cell as a precursor to the separation of the cell into two daughter cells

telophase

stage of mitosis during which chromosomes arrive at opposite poles decondense and are surrounded by a new nuclear envelope

tumor suppressor gene

segment of DNA that codes for regulator proteins that prevent the cell from undergoing uncontrolled division

A diploid cell has_______ the number of chromosomes as a haploid cell. a. one-fourth b. half c. twice d. four times

c. twice

An organism’s traits are determined by the specific combination of inherited _____. a. cells. b. genes. c. proteins. d. chromatids

b. genes

The first level of DNA organization in a eukaryotic cell is maintained by which molecule? a. cohesin b. condensin c. chromatin d. histone

d. histone

Identical copies of chromatin held together by cohesin at the centromere are called _____. a. histones. b. nucleosomes. c. chromatin. d. sister chromatids

d. sister chromatids

Chromosomes are duplicated during what stage of the cell cycle? a. G1 phase b. S phase c. prophase d. prometaphase

b. S phase

Which of the following events does not occur during some stages of interphase? a. DNA duplication b. organelle duplication c. increase in cell size d. separation of sister chromatids

d. separation of sister chromatids

The mitotic spindles arise from which cell structure? a. centromere b. centrosome c. kinetochore d. cleavage furrow

b. centrosome

Attachment of the mitotic spindle fibers to the kinetochores is a characteristic of which stage of mitosis? a. prophase b. prometaphase c. metaphase d. anaphase

b. prometaphase

Unpacking of chromosomes and the formation of a new nuclear envelope is a characteristic of which stage of mitosis? a. prometaphase b. metaphase c. anaphase d. telophase

d. telophase

Separation of the sister chromatids is a characteristic of which stage of mitosis? a. prometaphase b. metaphase c. anaphase d. telophase

c. anaphase

The chromosomes become visible under a light microscope during which stage of mitosis? a. prophase b. prometaphase c. metaphase d. anaphase

a. prophase

The fusing of Golgi vesicles at the metaphase plate of dividing plant cells forms what structure? a. cell plate b. actin ring c. cleavage furrow d. mitotic spindle

a. cell plate

At which of the cell-cycle checkpoints do external forces have the greatest influence? a. G1 checkpoint b. G2 checkpoint c. M checkpoint d. G0 checkpoint

a. G1 checkpoint

What is the main prerequisite for clearance at the G2 checkpoint? a. cell has reached a sufficient size b. an adequate stockpile of nucleotides c. accurate and complete DNA replication d. proper attachment of mitotic spindle f ibers to kinetochores

c. accurate and complete DNA replication

If the M checkpoint is not cleared, what stage of mitosis will be blocked? a. prophase b. prometaphase c. metaphase d. anaphase

d. anaphase

Which protein is a positive regulator that phosphorylates other proteins when activated? a. p53 b. retinoblastoma protein (Rb) c. cyclin d. cyclin-dependent kinase (Cdk)

d. cyclin-dependent kinase (Cdk)

Many of the negative regulator proteins of the cell cycle were discovered in what type of cells? a. gametes b. cells in G0 c. cancer cells d. stem cells

c. cancer cells

Which negative regulatory molecule can trigger cell suicide (apoptosis) if vital cell cycle events do not occur? a. p53 b. p21 c. retinoblastoma protein (Rb) d. cyclin-dependent kinase (Cdk)

a. p53

___________ are changes to the order of nucleotides in a segment of DNA that codes for a protein. a. Proto-oncogenes b. Tumor suppressor genes c. Gene mutations d. Negative regulators

c. gene mutations

A gene that codes for a positive cell-cycle regulator is called a(n) _____. a. kinase inhibitor. b. tumor suppressor gene. c. proto-oncogene. d. oncogene.

c. proto-oncogene

A mutated gene that codes for an altered version of Cdk that is active in the absence of cyclin is a(n) _____. a. kinase inhibitor. b. tumor suppressor gene. c. proto-oncogene. d. oncogene.

d. oncogene

Which molecule is a Cdk inhibitor that is controlled by p53? a. cyclin b. anti-kinase c. Rb d. p21

d. p21

Which eukaryotic cell-cycle event is missing in binary fission? a. cell growth b. DNA duplication c. karyokinesis d. cytokinesis

c. karyokinesis

FtsZ proteins direct the formation of a _______ that will eventually form the new cell walls of the daughter cells. a. contractile ring b. cell plate c. cytoskeleton d. septum

a. contractile ring