Ch. 11 Meiosis & Sexual Reproduction

What results when gametes unite; fertilized egg that contains one set of chromosomes?

zygote

What are matched pairs containing the same genes in identical locations along their lengths?

homologous chromosomes

What is nuclear division that forms haploid cells from diploid cells?

meiosis

What is it when a single parent splits to produce a clone?

asexual reproduction

Eukaryotes use __ to asexually reproduce

Prokaryotes/bacteria use __ __ to asexually reproduce

• mitosis

• binary fission

What type of reproduction is the union of parent cells (like egg and sperm) to form a zygote?

sexual reproduction

What is the union of two haploid cells from two individual organisms?

fertilization

What is the number of sets of chromosomes in a cell or organism?

ploidy

What are chromosomes 1-22; any chromosome that is not a sex chromosome?

autosomes

What are x and y chromosomes?

sex chromosomes

What is the first round of meiotic cell division; reduction division since the ploidy level is reduced from diploid to haploid?

meiosis I

What is nuclear division that produces a daughter nuclei with each having ½ as many chromosome sets as the parental nucleus?

reduction division

What is the second round of meiotic cell division; sister chromatids are separated into individual chromosomes resulting in 4 haploid cells?

meiosis II

What is the first part of meiosis I that is focused on cell growth, DNA is replicated, and the cell undergoes the final preparations for meiosis?

interphase

What is the primary phase responsible for the genetic variation that meiosis gives; chromosomes condense, nuclear membrane breaks down, mitotic spindle fibers form, and homologous chromosomes pair?

prophase I

What is the tight pairing of homologous chromosomes?

synapsis

What is the protein lattice that forms between homologous chromosomes during prophase I, supporting crossover?

synatonemal complex

What is the structure that forms at the crossover points after genetic material is exchanged?

chiamata

What is the exchange of genetic material between non-sister chromatids resulting in chromosomes that incorporates genes from both parents of the organism?

crossover

What are two duplicated homologous chromosomes (four chromatids) bound together by chiasmata during prophase I?

tetrad

What phase of meiosis I includes spindle fiber microtubules attached to the kinetochore proteins at the centromere, homologs held together at chiasmata, and nuclear envelope is completely broken down?

prometaphase I

What phase of meiosis includes homologous chromosomes arranged at the cell equator while maternal and paternal chromatids randomly mix and migrate to poles creating additional genetic variation among daughter cells?

metaphase I

What phase of meiosis includes the first cycle where the cell is considered to be in a haploid state as the microtubules pull tetrads apart and the chiasmata is broken by sister chromatids that remain attached at the centromere?

anaphase I

What phases of meiosis include the chromosomes separating and arriving at opposite poles and cells separated by cytokinesis?

telophase I and cytokinesis

What is the brief period of rest between meiosis I and II?

interkinesis

What phase of meiosis includes chromosomes recondensing (if they were decondensed in telophase I) and if centromeres were duplicated they migrate to opposite poles and new spindles form?

prophase II

What phase of meiosis II includes the nuclear envelope completely disappearing, spindles fully formed, and each sister chromatid forms a kinetochore and attaches microtubules from opposite poles?

prometaphase II

What phases of meiosis includes sister chromatids aligning on the mid-plane and then sister chromatids separate and move towards opposite poles?

metaphase II and anaphase II

What are proteins that form a complex that seals sister chromatids together at their centromeres until anaphase II?

cohesin

What phases of meiosis include chromatids arriving at opposite poles and decondensing, nuclear envelope forms around chromosomes (decondenses), and the two cells are separated into four unique haploid (daughter) cells?

telophase II and cytokinesis

What is the process where immature sperm cells are produced?

spermatogenesis

What is the process to produce immature egg cells?

oogenesis

Sexual reproduction = __ + __

• meiosis

• fertilization

What is the sequence of events in the development of an organism and the production of cells that produce offspring?

life cycle

What are the three main categories of life cycles in multicellular organisms?

• diploid-dominant

• haploid-dominant

• alternation of generations

What life cycle includes the organism spending majority of their life in the diploid state, the only time the organism undergoes reduction is to produce gametes, and two gametes fuse during fertilization to form a diploid zygote?

diploid-dominant

What is a specialized cell line that produces gametes?

germ cells

What life cycle includes the organism spending majority of their life in the haploid state, diploid stage is short-lived while two haploid cells fuse two form a zygote, and the diploid zygote immediately undergoes meiosis to form 4 haploid spores?

haploid-dominant

What is a haploid cell that can produce a haploid multicellular organism or can fuse with another __ to form a diploid cell?

spore

What life-cycle type is where the diploid and haploid stages alternate?

alternation of generations

What is the multicellular haploid life-cycle stage that produces gametes?

gameotophyte

What is the multicellular diploid life-cycle stage that produces haploid spores by meiosis?

sporophyte