Chapter 4

Diplotene

________: fourth stage of prophase I, synaptonemal complex dissolves, tetrad of 4 chromatids visible, crossover points appear as chiasmata holding non- sister chromatids together.

Prometaphase

________: spindle forms and sister chromatids attach to microtubules from opposite centrosomes, nuclear envelope breaks down, microtubules invade nucleus and connect to kinetochores in centromere of each chromatid.

Telophase

________: chromosomes de- condense and are enclosed in two nuclei, nuclear envelope forms around each group of chromatids, nucleoli re- form, spindle fibers disperse.

Metaphase

________: chromosome align at cell equator with sister chromatids facing opposite poles, forces on chromosomes from each pole are at equilibrium.

Centrioles

________: core of centrosome, not found in plant cells.

cleavage

Cytokinesis in animals: contractile ring helps form ________ furrow.

Interkinesis

________: similar to interphase, but without chromosomal duplication.

Autosomes

________: all chromosomes except x and y.

Metaphase chromosomes

________ can be classified by centromere position.

Fertilization

________ is the union of haploid gametes to produce diploid zygotes.

Anaphase

________: centromeres divide simultaneously, kinetochore microtubules shorten and pull separated sister chromatids to opposite poles.

G2

________: Growth, synthesis of proteins for mitosis.

Anaphase I

________: centromere does not divide, chiasmata dissolve, homologous chromosomes move to opposite poles.

Zygotene

________: second stage of prophase I, homologous chromosomes enter synapsis.

Sister chromatids

________: identical copies of replicated chromosome.

Pachytene

________: third stage of prophase I, synapsis complete, crossing over occurs.

Cytokinesis

________ in plants: cell plate forms near equator.

Meiosis generates

________ haploid gametes.

Diakinesis

________: fifth stage of prophase I, chromatids thinken and shorten, nuclear membrane breaks down, spindle forms.

Acrocentric

________: centromere is near one end.

Nonhomologs

________: unrelated sets of genes.

Prophase

________: chromosomes condense and become visible, centrosomes move apart toward opposite poles, nucleoli disappears.

SRY

________: primary determinant of maleness.

Leptonene

________: first stage of prophase I, chromosomes thicken and become visible, centrosomes move toward opposite poles.

G1

________: cell growth, gap before chromosome duplication.

Karyotype

________: micrograph of strained chromosomes arranged in homologous pairs.

Telophase I

________: nuclear envelope re- forms, resultant cells have half the number of chromosomes.

Centrosome

________: microtubule organizing venter near the nuclear envelope.

Meiosis

________ I: homologs pair, cross over, and then segregate.

Prophase I

________: homologs pair and are help together by synaptonemal complex, crossing over occurs.

Meiosis II

________: sister chromatids separate to opposite poles.

Homogametic sex

________: gender with 2 of the same gametes (XX or ZZ)

Cell cycle

________: repeating pattern of cell growth and division.

Somatic cells

________: most cells in organism, in G0 or actively going through mitosis.

Cytokinesis

________: parent cells split into 2 daughter cells, cytoplasm divides.

Metaphase

________ I: tetrads line up along metaphase plate, chromosomes attach to fibers from opposite poles, sister chromatids attach to fibers from the same pole.

metacentric

centromere is in the middle

acrocentric

centromere is near one end

sister chromatids

identical copies of replicated chromosome

homologs

same set of genes, but different alleles

nonhomologs

unrelated sets of genes

Karyotype

micrograph of strained chromosomes arranged in homologous pairs

homogolous chromosomes

same size, shape, and banding

autosomes

all chromosomes except x and y

sex chromosomes

unpaired x and y

heterogametic sex

gender with 2 different gametes (XY or ZW)

Homogametic sex

gender with 2 of the same gametes (XX or ZZ)

SRY

primary determinant of maleness

Cell cycle

repeating pattern of cell growth and division

3 parts of interphase

G1, S, G2

centrosome

microtubule organizing venter near the nuclear envelope

centrioles

core of centrosome, not found in plant cells

G1

cell growth, gap before chromosome duplication

S

chromosome replication, creation of sister chromatids

G2

Growth, synthesis of proteins for mitosis

Prophase

chromosomes condense and become visible, centrosomes move apart toward opposite poles, nucleoli disappears

Prometaphase

spindle forms and sister chromatids attach to microtubules from opposite centrosomes, nuclear envelope breaks down, microtubules invade nucleus and connect to kinetochores in centromere of each chromatid

Metaphase

chromosome align at cell equator with sister chromatids facing opposite poles, forces on chromosomes from each pole are at equilibrium

Anaphase

centromeres divide simultaneously, kinetochore microtubules shorten and pull separated sister chromatids to opposite poles

Telophase

chromosomes de-condense and are enclosed in two nuclei, nuclear envelope forms around each group of chromatids, nucleoli re-form, spindle fibers disperse

Types of microtubules

astral, kinetochore, and polar

Cytokinesis

parent cells split into 2 daughter cells, cytoplasm divides

Cytokinesis in animals

contractile ring helps form cleavage furrow

Cytokinesis in plants

cell plate forms near equator

Mitosis checkpoint 1

is cell sufficient size

Mitosis checkpoint 2

have chromosomes been completely duplicated

Mitosis checkpoint 3

have all chromosomes arrived and aligned at metaphase plate

Somatic cells

most cells in organism, in G0 or actively going through mitosis

Germ cells

precursors to gametes, set aside during embryogenesis, become incorporated into reproductive organs, undergo meiosis

Meiosis I

homologs pair, cross over, and then segregate

Prophase I

homologs pair and are help together by synaptonemal complex, crossing over occurs

Leptonene

first stage of prophase I, chromosomes thicken and become visible, centrosomes move toward opposite poles

Zygotene

second stage of prophase I, homologous chromosomes enter synapsis

Pachytene

third stage of prophase I, synapsis complete, crossing over occurs

Diplotene

fourth stage of prophase I, synaptonemal complex dissolves, tetrad of 4 chromatids visible, crossover points appear as chiasmata holding non-sister chromatids together

Diakinesis

fifth stage of prophase I, chromatids thinken and shorten, nuclear membrane breaks down, spindle forms

Metaphase I

tetrads line up along metaphase plate, chromosomes attach to fibers from opposite poles, sister chromatids attach to fibers from the same pole

Anaphase I

centromere does not divide, chiasmata dissolve, homologous chromosomes move to opposite poles

Telophase I

nuclear envelope re-forms, resultant cells have half the number of chromosomes

Interkinesis

similar to interphase, but without chromosomal duplication

Meiosis II

sister chromatids separate to opposite poles

Prophase II

chromosomes condense, centrioles move toward poles, nuclear envelope breaks down

Metaphase II

chromosomes align at metaphase plate, sister chromatids attach to spindle fibers from opposite poles