Developmental Biology Laboratory _ Spermatogenesis in the Grasshopper

meiosis

sexually reproducing animals and plans have their reproductive cells and they divide by ________

gametogenesis

meiosis is also called what?

Spermatogenesis and oogenesis

gametogenesis is divided into two, __________ and ______________

spermatogenesis

maturation division of sperm cells by males

ovogenesis

other term for oogenesis

oogenesis or ovogenesis

maturation division of egg cells by females

haploid (n)

after cell division, one gamete will have one of each chromosome

diploid (2n)

has two copies of each chromosome except the X and Y chromosome of the female and male, respectively

aneuploidy

mistakes usually occur and will result to __________

Anaphase I

In this phase, chiasmata are released; chromosomes disjoin, and the kinetochore moves the chromosomes to the poles with the aid of the spinde

Anaphase II

In this phase, sister chromatids segregate from one another

Anaphase I and Anaphase II

The two divisions that produce four haploid cells from a single diplod cell

spermatogonium

large nucleus which exhibits a fine network of chromatin

spermatogonium

some of these cells are grouped around an apical cell

primary spermatocyte

these cells are produced from the sprematogonial division

period of growth, increase in the amount of cytoplasm, and changes in the behavior of chromosomes

primary spermatocyte undergo here after being produced from the spermatogonial division

leptotene stage

chromatin threads ar long and delicate

become polarized with their ends attached to the nuclear membrane near the region of the centrioles

leptotene stage

their free ends form a large loops toward the center of the nucleus as in bouquet

bouquet stage

leptotene is also called as?

diploid ; condensed

leptotene threads are _______ in number; sex chromosome is ________

zygotene stage ; synapsis

_______ _____ is characterized by side-to-side of the leptotene threads which begin at the polarized ends of the loops, a condition called _________

zygotene stage

threads become shorter and thicker progressively

zygotene stage

sex chromosomes begin to elongate and swell

pachytene stage

synapsis which is the joining of the homologous chromosomes is completed

pachytene

_______ threads are short and thich and become twisted spirally about each other

they arre double in nature

pachytene stage

chromatin threads consist of two pairs of chromosomes called bivalent and a complex of four chromatids called a tetrad

pachytene stage

synaptic condition allows the reshuffling and redistribution of hereditary materials between the homologous chromosomes which is exact an specific, taking place point for point betweeen the homologues

synaptonemal complex

the mechanism that holds the homologues together

diplotene stage

splitting of some parts of the bivalents marks the beginning of this stage, although in places where crossing over has taken place, chromosomes are still united by a chiasma

diplotene stage

chromosomes come to lie near the periphery of the nucleus

diplotene stage

sex chromosomes is in the form of a blunt rod

diplotene stage

nucleolus begins to disappear

diakinesis stage

as chiasma terminalizes, the longitudinal splitting is more pronounced in each element of the bivalent chromosome forming quadruple bodies or tetrads

diakinesis stage

tetrads are typically short and stout assuming shapes of Y’s, X’s, 8’s and circles

diakinesis stage

nucleolus disappears, nuclear membrane degenerates, and spindle is formed

metaphase 1

the following stage leads to the formation of a metaphase figure and the chromosomes including the sex chromosomes are aligned at the equator of the cell

anaphase 1

thee tetrads divide into dyads (sex chromosome is already a dyad not having conjugated). As the homologues separate each pole receives a longitudinally double chromosome of each pair

anaphase 1

this stage produces secondary spermatocytes

reduction division

anaphase 1 is also called as?

telophase 1

chromosomes reached the poles and they may remain condensed for a while

cytokinesis

nucleolus and nuclear membrane reform a _________ sets in

telophase 1

this division has separated the chromosomal complement into two monoploid nuclei

spermateliosis

after telophase 1, division II will follow and will proceed to ___________