Lesson 13 Definitions

Question 1

gamete

Answer 1

ova/sperm

Question 2

sperm

Answer 2

formed in the testes, produces four viable cells of the same size, each propelled by a flagellum

Question 3

fertilization

Answer 3

occurs in fallopian tube, consists of the penetration and fusion phases

Question 4

corona radiata

Answer 4

supplies proteins to cell

Question 5

zygote

Answer 5

fertilized egg cell with diploid number

Question 6

cleavage

Answer 6

first cell division

Question 7

blastocyst

Answer 7

fertilized egg after five or six days

Question 8

gastrula

Answer 8

forms during first two weeks

Question 9

embryo

Answer 9

zygote after first cell division

Question 10

neural tube

Answer 10

the embryonic precursor to the central nervous system, which is made up of the brain and spinal cord

Question 11

neurulation

Answer 11

the folding process in vertebrate embryos, which includes the transformation of the neural plate into the neural tube. The embryo at this stage is termed the neurula.

Question 12

hox genes

Answer 12

genes that specify regions of the body plan of an embryo along the head-tail axis of animals. Hox proteins encode and specify the characteristics of ‘position’, ensuring that the correct structures form in the correct places of the body.

Question 13

fetus

Answer 13

embryo after 8 weeks

Question 14

yolk sac

Answer 14

food source until hatching (helps form umbilical cord in humans)

Question 15

allantois

Answer 15

stores metabolic wastes of embryo

Question 16

amnion

Answer 16

fluid filled sac that cushions embryo

Question 17

chorion

Answer 17

fetal part of placenta. lines the inner surface of the shell, participates in gas exchange. (chorionic villi interact with placenta in mammals)

Question 18

placenta

Answer 18

membrane that separates the mother’s blood from the baby’s blood

Question 19

decidua basalis

Answer 19

mother’s part of placenta

Question 20

umbilical cord

Answer 20

connects baby to placenta

Question 21

ectoderm

Answer 21

skin, brain

Question 22

mesoderm

Answer 22

muscle, blood

Question 23

endoderm

Answer 23

inner organs