what is the defenition of gametogenesis
production of gametes int he sex organs
how are haploid gametes formed
cells of germinal epithelium undergo mitotic + meiotic divisons
whats the significance of meiosis in gametogenesis
reduces the chromosome number by half to one set
introduces genetic variation
significance of mitosis in gametogenesis
capability to produce large numbers of gametes
where are the male germ cells
in outermost layer of cells in the seminiferous tubule wall
mitosis
what are the 6 steps of spermatogenesis
germinal epithelium
spermatogonia
primary spermatocytes
secondary spermatocyes
spermatids
spermatozoa
next step after germinal epithelium cells (1-2)
mitosis to spermatogonia
next step after spermatogonia (2-3)
primary spermatocytes
next step after primary spermatocytes (3-4)
meiosis 1 to secondary spermatocytes
next step after secondary spermatocytes (4-5)
meiosis 2 to spermatids
next step after spermatids (5-6)
gain tail to form spermatozoa
what does the head of sperm contain
haploid nucleus and anterior end which acrosome lysosome which contains enzymes used at fertilisation
whats the lysosome in head of sperm
acrosome - contains enzyme used at fertilisation
whats in the middle piece of the sperm
packed with mitochondria - provide ATP for movement
whats the point of the flagellum of the sperm
lashing moevemt to move the sperm
where are spermatozoa produced
in semi-neferous tubule
what is the job of sertoli cells
protect and nourish spermatozoa
what protects and nourishes spermatozoa
sertoli cells
why is meisosis important in life cycle of sexually reproducing organism
increase genetic variation
half number of chromosomes so diploid number restored at fertilisation
how does meiosis increase genetic variation in the gametes
crossing over at prophase 1
random assortment of chromosomes during mitosis 1/2
whats the advantage of variation introduced by meisosis
advantageous alleles may be added to gene pool
some will be better adapted, survive, reproduce, pass on genes / alleles
