Exam 3- Ch. 10

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 conjunction with cyclin-dependent kinases to help regulate the cell cycle by phosphorylating key proteins; the concentrations of cyclins fluctuate throughout the cell cycle

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 (name origin: Filamenting temperature-sensitive mutant Z)

G0 phase

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

G1 phase

(also, first gap) first phase of interphase centered on cell growth during mitosis

G2 phase

(also, second gap) third phase of interphase during which the cell undergoes final preparations for mitosis

gamete

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

gene

physical and functional unit of heredity, a sequence of DNA that codes for a protein.

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; diploid organisms have pairs of homologous chromosomes (homologs), with each homolog derived from a different parent

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

miotic 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 align

metaphase plate

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

Mitosis (karyokinesis)

period of the cell cycle during which the duplicated chromosomes are separated into identical nuclei; includes prophase, prometaphase, metaphase, anaphase, and telophase

mitotic phase

period of the cell cycle during which duplicated chromosomes are distributed into two nuclei and cytoplasmic contents are divided; includes karyokinesis (mitosis) and cytokinesis

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 (ori)

region of the prokaryotic chromosome where replication begins (origin of replication)

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

retinoblasma 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

What is the difference in chromosome constitution between somatic cells and gametes

Somatic cells have 2 matched sets of chromosomes (46), diploid, 1 set of homologous chromosomes, and x and y are not homologous

Gametes have half the number of chromosomes (23), eggs and sperm cells, haploid

What are the macromolecules that comprise chromosomes

nucleic acids and protein

Label the chromosomes

A. Homologous Chromsomes

B. Centromere

C. Kinetochore

D. Synaptonemal Complex

E. Sister Chromatids

What is the function of mitosis and cytokinesis

Mitosis is the first step and consists of nuclear division (moving and rearranging the nucleus)

Cytokinesis is the second step and consists of the moving and rearranging of the cytoplasm until the parent cell separates into 2 daughter cells (clones)

Label each phase and describe each phase of the cell cycle

A. Interphase- the time for normal growth and preparation for cell division

B. Prophase- mitosis

C. Metaphase- mitosis

D. Anaphase- mitosis

E. Telophase- mitosis

F. Cytokinesis- cells divide

Label each phase and describe each phase of mitosis/ karyokinesis

A. Prophase- nuclear envelope breaks down, organelles disperse to edges of the cell, centrosomes begin migration to poles, microtubules push apart, sister chromatids coil tighter

B. Prometaphase- sister chromatids develop kinetochore in the centromeric region attaching chromatids to spindle microtubules, polar microtubules contribute to cell elongation

C. Metaphase- chromosomes line up along the metaphase plate, sister chromatids remain attached by cohesin proteins

D. Anaphase- chromatids separate, sister chromatids move in opposite directions toward centrosomes, cell elongates

E. Telophase- chromosomes reach opposite poles and de-condense, spindles depolymerize to form cytoskeletal components, nuclear envelopes form around chromosomes, nucleosomes appear within the nuclear area

What role do microtubules play during mitosis

microtubules extend outward from duplicated centrosomes to form the mitotic spindle, which is responsible for the separation and distribution of chromosomes to daughter cells

What role do checkpoints play at different points in the cell cycle

G1- checks for genomic DNA damage

G2- ensures all chromosomes have been replicated and that DNA is not damaged

M- makes sure the sister chromatids are attached to spindle microtubules

When do cyclins present in the cell cycle?

Different cyclins vary at different cell checkpoints

What internal signals halt the cell cycle at G2 and M checkpoints

Cyclin dependent kinases

How do external signals function to promote cell division

growth hormones encourage cell growth, and physical signals such as when a cell touches another cell, causes it stops dividing.

What changes cause normal cells to transform into cancer cells

increased cell division, decreased apoptosis, or mutated p53 or oncogenes

What are the differences between benign and malignant tumors

Benign tumors generally don't invade and spread, malignant cells are more likely to metastasize or travel to other areas of the body.