Biology Lab 7
How many sperm get to the egg
1
How fast can sperm travel
1/3 an hour
When do the ovaries of the female fetus become active
11th week
How many sperm are produced each day
200,000,000
How many sperm are present in an ejaculation
200,000-500,000
How many chromosomes are in an egg and a sperm
23
How soon does an egg have to be fertilized
24 hours
When can the fetus hear voices
24 weeks
How many days after fertilization does the heart start beating
28 days
How many distinct layers of cells do developing sea stars have at the blastula stage?
3
How many distinct layers of cells do developing sea start have at the blastula stage?
3
When do the testicles of the male fetus descend into the scrotum
30th week
How many weeks of pregnancy are needed for complete developement
38 weeks
Diploid
46 chromosomes
When does the embryo implant on the uterine wall
7 days
Asterias
A common sea star belonging to the invertebrate phylum Echinodermata
Blastomeres
After the first mitotic division
Optic vesicles
Become the eyes of the chick
Blastopore
Becomes the anus
Neural Tube
Becomes the brain and the spinal cord
Acrosome
Caps the nucleus and contains digestive enzymes enabling the sperm to dissolve a small hole in the membrane of the ovum for fertilization to take place
Holoblastic
Cleavage of the entire zygote
Germinal Disc
Contains the egg nucleus
Animal pole
Contains very little yolk
Chorion
Controls diffusion
Somites
Develop into the skeleton and skeletal muscles of the chick
Why must the eggshell be porous?
Diffusion of O2 and CO2
Fraternal twins
Double ovulation
Isolecithal
Evenly distributed yolk
Identical twins
First two daughter cells separate completely and each divides independently
Blastocoel
Fluid-filled cavity of the blastula
Limb buds
Form the legs
Neural folds
Form the neural grove
Ectoderm
Form the skin and the nervous system
Blastulation
Formation of a mass of cells containing a central cavity
Allantois
Forms a waste sac
Mesoderm
Forms muscular tissue and parts of the reproductive and circulatory system
Fertilization
Fusion of male and female gametes to form a zygote
What is the basic unit of heredity
Gene
How is movement important to a developing sea star?
Get away from predators
Blastula
Hallow ball of cells
How large is a frog zygote compared to that of a sea star?
It is larger
Primitive Streak
Linear furrow
Gastrulation
Movement of groups of cells which results in formation of rudimentary digestive tract.
Largest cell in a woman's body
Ovum
Meroblastic
Partial clevage
Vegetal pole
Primarily yolk
Archenteron
Primitive gut
What function does the shell have?
Protection
Yolks
Provides nutrients and potential energy to the developing embryo
Cleavage
Rapid mitotic divisions undergone by the zygote. No growth occurs, but the number of cells increase
How does the size of the unfertilized egg compare with that of the zygote?
Same size
How much yolk does a sea start have?
Small amount that is evenly distributed
Does the sperm or the egg determine the gender of the fetus
Sperm
Albumin
Supplies the embryo with water and food in addition to the yolk
Amnion
Surrounds the embryo
Yolk Sac
Surrounds the yolk
Where is the semen made
Testes
Yolk plug
The blastopore where cells are invaginating but is plugged by yolk cells that do not invaginate
How does the size of an embryo during early cleavage compare with that of the zygote?
They are the same size and there is no growth
How long can sperm travel
Two days
Telolecithal
Unequal distribution of yolk
Hormone hCG
Used to test if a woman is pregnant
Which are larger, animal pole cells or vegetal pole cells?
Vegetal poles
Endoderm
Will form the digestive tract
Are the four cells of approximately equal size?
Yes
Is the sea star embryo growing during cleavage?
no
