Bio Ch 42

Question 1

Fertilization

Answer 1

union of a sperm and an egg to form a zygote

Question 2

Development

Answer 2

includes all the changes that occur during the life cycle of an organism

Question 3

Embryo

Answer 3

during the early stages of development, an organism is called this

Question 4

Cleavage

Answer 4

cell division without growth

Question 5

Morula

Answer 5

solid ball of cells

Question 6

Blastula

Answer 6

hollow ball of cells having a fluid-filled cavity (blastocoel)

Question 7

Blastocoel

Answer 7

fluid-filled cavity in the blastula

Question 8

Yolk

Answer 8

dense nutrient material in a hard-shelled egg

Question 9

Gastrulation

Answer 9

tissue stages of development involve the formation of a gastrula

Question 10

Gastrula

Answer 10

forms from the blastula; 2 stages - early and late

Question 11

Ectoderm

Answer 11

outer layer of cells

Question 12

Endoderm

Answer 12

inner layer of cells

Question 13

Blastopore

Answer 13

pore/hole created by invagination

Question 14

Mesoderm

Answer 14

in addition to ectoderm and endoderm, the late gastrula has a middle layer of cells called this

Question 15

Germ layers

Answer 15

ectoderm, mesoderm, and endoderm are called the embryonic ____ ______

Question 16

Notochord

Answer 16

newly formed mesoderm cells lie along the main longitudinal axis of the animal and coalesce to form this dorsal supporting rod

Question 17

Neural plate

Answer 17

thickening of cells first seen along the dorsal surface of the embryo

Question 18

Neural tube

Answer 18

neural folds develop on either side of the neural groove, which becomes this when these folds fuse

Question 19

Cellular differentiation

Answer 19

occurs when cells become specialized in structure and function

Question 20

Morphogenesis

Answer 20

produces the shape and form of the body; one of the earliest indicators is cell movement

Question 21

Pattern formation

Answer 21

how tissues and organs are arranged in the body

Question 22

Apoptosis

Answer 22

programmed cell death

Question 23

Totipotent

Answer 23

having the ability to generate the entire organism, and therefore must contain all the instructions needed by any other specialized cell in the body

Question 24

Maternal determinants

Answer 24

egg is known to contain these substances in the cytoplasm which influence the course of development

Question 25

Cytoplasmic segregation

Answer 25

parceling out of maternal determinants as mitosis occurs

Question 26

Induction

Answer 26

ability of one embryonic tissue to influence the development of another tissue

Question 27

Homeotic genes

Answer 27

selector genes that select for segmental identity (dictate which body parts arise from the segments)

Question 28

Homeobox

Answer 28

homeotic genes have all been found to share a structural feature called this; a sequence of nucleotides that encodes a 60-amino acid sequence (homeodomain)

Question 29

Homeodomain

Answer 29

a 60-amino acid sequence encoded by a homeobox

Question 30

Embryonic development

Answer 30

1st part of human development when major organs are formed

Question 31

Extraembryonic membranes

Answer 31

membrane that is not a part of the embryo but is necessary to the continued existence and health of the embryo

Question 32

Chorion

Answer 32

egg membrane lying next to the shell; carries on gas exchange

Question 33

Amnion

Answer 33

egg membrane containing the protective amniotic fluid, which bathes the developing embryo

Question 34

Allantois

Answer 34

part of the egg that collects nitrogenous wastes

Question 35

Yolk sac

Answer 35

part of the egg that surrounds the remaining yolk, which provides nourishment

Question 36

Blastocyst

Answer 36

fluid-filled cavity with a single layer of outer cells (trophoblast), and an inner cell mass

Question 37

Trophoblast

Answer 37

single layer of outer cells of a blastocyst that provides nourishment for the embryo

Question 38

Implantation

Answer 38

at the end of the 1st week, the embryo begins this process in the wall of the uterus

Question 39

Human Chorionic Gonadotropin (HCG)

Answer 39

trophoblast secretes this hormone that is the basis for the pregnancy test and that serves the maintain the corpus luteum past the time it normally disintegrates

Question 40

Embryonic disk

Answer 40

inner cell mass has flattened into this during the 2nd week of pregnancy; composed of 2 layers of cells (ectoderm and endoderm); elongates to form the primitive streak

Question 41

Chorionic villi

Answer 41

treelike projections of the chorion

Question 42

Umbilical cord

Answer 42

connects the developing embryo to the placenta

Question 43

Placenta

Answer 43

mammalian structure that functions in gas, nutrient, and waste exchange between embryonic and maternal cardiovascular systems

Question 44

Menopause

Answer 44

period in a woman's life during which the ovarian and uterine cycles cease; usually occurs between ages 45 & 55