Fertilization

Question 1

gamerogenesis

Answer 1

process of making gametes

Question 2

gonad

Answer 2

organ consisting of somatic cells with germ cells inside

Question 3

germ cells

Answer 3

diploid; divide mitotically to make more diploid germ cells; divide meiotically to make haploid gametes

Question 4

primordial germ cells

Answer 4

a few cells set aside early in development which migrate into developing gonads and generate the germ line

Question 5

inert genome hypothesis

Answer 5

germ line genomes stay inert or non-transcribing

Question 6

germ cell migration in flies

Answer 6

1. cells are displaced into posterior midgut during the movement of gastrulation
2. PGCs migrate from posterior midgut to the visceral mesoderm
3. PGCs associate with developing gonad pirmordium
4. PGCs migrate to the gonads

Question 7

where are PGCs first seen in mammals?

Answer 7

outside the embryo proper

Question 8

germ cell migration in mammals

Answer 8

1. use fibronectin in ECM to migrate (integrin is receptor)
2. chemotax toward diffusible factor SDF1 made by genital ridge
3. respond to stem cell factor SCF and proliferate

Question 9

SDF1

Answer 9

diffusible factor that causes PGCs to chemotax; made by genital ridge

Question 10

spermatogenesis

Answer 10

formation of haploid sperm cell

Question 11

spermiogenesis

Answer 11

differentiation of those cells into specialized cells that can perform their function

Question 12

functions sperm delivers to egg

Answer 12

haploid nucleus; centriole

Question 13

where does sperm development take place?

Answer 13

seminiferous tubules in testis

Question 14

sertoli cells

Answer 14

in seminiferous tubules; provide support, nourishment, and signals for developing germ cells

Question 15

where does spermatogenesis take place?

Answer 15

in the lumen between the seminiferous tubules and basal lamina; early stages are closer to basal lamina

Question 16

process of spermiogenesis

Answer 16

1. centriole produces flagellum at posterior end of sperm cell
2. golgi forms acrosomal vesicle at future anterior end
3. mitochondria collect around the flagellum and become incorporated into the midpiece

Question 17

phases of oogenesis

Answer 17

1. proliferation
2. maturation
3. meiosis and ovulation

Question 18

graafian follicle

Answer 18

mature mammalian oocyte

Question 19

hormonal regulation of ovulation in humans

Answer 19

1. pulse of FHS and LH (pituitary) and estrogen (ovaries) leads to ovulation
2. corpus luteum makes progesterone which prepares uterine lining for implantation, inhibits further ovulation

Question 20

what secretes FHS and LH?

Answer 20

pituitary

Question 21

what secretes estrogen?

Answer 21

ovaries

Question 22

hyperactivation

Answer 22

occurs during capacitation; sperm swim at higher velocity; mediated by opening of sperm-specific Ca2+ channels in sperm tail

Question 23

zona pellucida

Answer 23

glycoprotein matrix made by oocyte; binds sperm and initiates acrosomal reaction after sperm is bound

Question 24

sperm binding

Answer 24

1. sperm binds to ligand secreted by oviduct and coating the zona pellucida
2. SED1 binds to ZP complex on zona
3. sperm GalT crosslink to N-acetylglucosamine sugar residues on ZP3
4. clustering of GalT in sperm membrane activates G proteins that open Ca2+ channels and initiate acrosome rxn

Question 25

acrosome reaction

Answer 25

once sperm is bound to ZP3; leads to Ca2+ influx into sperm; acrosomal membrane disappears; digest hole through zona pellucida

Question 26

functions of fertilization

Answer 26

1. transmit genes from parents to offspring | 2. initiate in the egg the eggg cytoplasm reactions that enable development to proceed

Question 27

4 major events of conception

Answer 27

1. contact and recognition between the sperm and egg; ensures that the sperm and egg are from the same species 2. regulation of sperm entry into egg; only one sperm nucleus can unite with egg nucleus 3. fusion of genetic material of sperm and egg 4. activation of egg metabolism to start development

Question 28

acrosome

Answer 28

modified secretory vesicle; digests proteins and complex sugars on outer coverings of egg

Question 29

acrosomal process

Answer 29

region of globular actin proteins that lies between sperm nucleus and acrosomal vesicle; used to extend acrosomal process

Question 30

sperm head

Answer 30

acrosome and nucleus

Question 31

flagellum

Answer 31

for sperm movement; motor protein = axoneme

Question 32

mid-piece

Answer 32

sperm; contain mitochondria; provides ATP to flagellum

Question 33

Kartagener's syndrome

Answer 33

individuals lack dynein in all their ciliated and flagellated structures, rendering them immotile; men with this are sterile

Question 34

capacitation

Answer 34

final stages of mammaliam sperm maturation; does not occur until sperm has been inside female reproductive tract for some period of time

Question 35

oocyte

Answer 35

egg before it reaches the stage of meiosis at which it is fertilized

Question 36

vitelline envelope

Answer 36

ECM outside cell membrane that forms fibrous mat around the egg; involved in sperm-egg recognition

Question 37

egg jelly

Answer 37

outside vitelline envelope; used to attract or activate sperm

Question 38

cortex

Answer 38

immediately beneath cell membrane of eggs; gel-like cytoplasm; contains actin

Question 39

cortical granules

Answer 39

membrane bound, golgi derived structures; contain proteolytic enzymes; homologous to acrosomal vesicle of sperm; contain mucopolysaccharides, adhesive glycoproteins, and hyaline protein

Question 40

what are the major components stored in the egg cytoplasm?

Answer 40

nutritive proteins, ribosomes and tRNA, mRNAs, protective chemicals

Question 41

5 molecular changes important for mammalian sperm capacitatioin

Answer 41

1. sperm cell membrane is altered by the removal of cholesterol by albumin proteins the in the female reproductive tract 2. particular proteins or carbs on sperm surface are lost 3. membrane potential of the sperm cell membrane becomes more negative as K+ leaves sperm 4. protein phosphorylation 5. outer acrosomal membrane changes and come into contact with the sperm cell membrane to prepare it for fusion