Biology Developmental

Question 1

Cleavage increases the ___ ratio of each cell, thereby improving gas and nutrient exchange

Answer 1

surface-area-to-volume

Question 2

The first complete ___ of a zygote occurs approximately 32 hours after fertilization

Answer 2

cleavage

Question 3

The second cleavage of a ___ occurs after 60 hours, and the third cleavage after approximately 72 hours, at which point the eight-celled embryo reaches the uterus

Answer 3

zygote

Question 4

As cell division continues, a solid ball of embryonic cells, known as the ___, is formed

Answer 4

morula

Question 5

___ begins when the morula develops a fluid-filled cavity called the blastocoel, which by the fourth day becomes a hollow sphere of cells called the blastula (blastocyst in mammals)

Answer 5

blastulation

Question 6

The outer layer of cells of the ___, called the trophoblast, provides nutrients to the embryo and develops into part of the placenta

Answer 6

blastula

Question 7

The two components of the fetal circulatory system are the ___ and the umbilical cord

Answer 7

placenta

Question 8

The placenta and the umbilical cord are outgrowths of the four extra-embryonic ___ formed during development: the amnion, chorion, allantois, and yolk sac

Answer 8

membranes

Question 9

The ___ is a thin, tough membrane containing a watery fluid called amniotic fluid

Answer 9

amnion

Question 10

___ acts as a shock absorber of external pressure during gestation and localized pressure from uterine contractions during labor

Answer 10

amniotic fluid

Question 11

___ formation begins with the chorion, a membrane that completely surrounds the amnion

Answer 11

placenta

Question 12

The ___ assists with transfer of nutrients from the mother to the fetus

Answer 12

chorion

Question 13

A third membrane, the ___, develops as an outpocketing of the gut

Answer 13

allantois

Question 14

The blood vessels of the allantoic wall enlarge and become the ___ vessels, which will connect the fetus to the developing placenta

Answer 14

umbilical

Question 15

The yolk sac, the site of early development of ___, becomes associated with umbilical vessels

Answer 15

blood vessels

Question 16

After week two, the embryo is fully implanted in the ___ and cell migrations transform the single cell layer of the blastula into a three-layered structure called a gastrula

Answer 16

uterus

Question 17

(primary germ layer) ___- “attracto”derm (things that attract us to others, such as cosmetic features and smarts)

Answer 17

ectoderm

Question 18

(primary germ layer) ___- “means”oderm (the means of getting around as an organism, such as bones and muscle; the means of getting around in the body, such as circulatory system; the means of getting around, such as the gonads

Answer 18

mesoderm

Question 19

(primary germ layer) ___ - linings of “endernal” organs (the digestive and respiratory tract, and accessory organs attached to these systems)

Answer 19

endoderm

Question 20

___ (outer layer): the lens of the eye, the retina, and the nervous system

Answer 20

ectoderm

Question 21

___ (middle layer): portions of digestive and respiratory organs

Answer 21

mesoderm

Question 22

___ (inner layer): parts of the liver, pancreas, thyroid, and bladder lining

Answer 22

endoderm

Question 23

By the end of ___, regions of the germ layers begin to develop into a rudimentary nervous system; this process is known as neurulation and starts before week three

Answer 23

gastrulation

Question 24

A rod of ___ cells called the notochord develops along the longitudinal axis of the embryo just under the dorsal layer of ectoderm

Answer 24

mesodermal

Question 25

The ___ has an inductive effect on the overlying ectoderm, causing it to bend inward and form a groove along the dorsal surface of the embryo

Answer 25

notochord

Question 26

The dorsal ___ folds on either side of the groove; these neural folds grow upward and finally fuse, forming a closed tube

Answer 26

ectoderm

Question 27

After a closed tube is formed with the dorsal ectoderm (neural tube), this gives rise to the ___ and spinal cord (central nervous system)

Answer 27

brain

Question 28

The cells at the tip of each neural fold are called ___

Answer 28

neural crest cells

Question 29

Neural crest cells migrate laterally and give rise to many components of the ___ nervous system

Answer 29

peripheral

Question 30

___: the body organs begin to form

Answer 30

organogenesis

Question 31

___: the organs increase in size, which is a continual process from infancy through adulthood

Answer 31

Growth

Question 32

___: eggs develop in women and sperm develop in men, which permits reproduction to occur

Answer 32

gametogenesis

Question 33

(first trimester) major ___ begin to develop

Answer 33

organs

Question 34

(first trimester) the cartilaginous ___ begins to turn into bone by the seventh week

Answer 34

skeleton

Question 35

(first trimester) At the end of the ___ month, the fetus is about 9 cm long

Answer 35

third

Question 36

(second trimester) The ___ begins to move around in the amniotic fluid, its face appears human, and its toes and fingers elongate

Answer 36

fetus

Question 37

(third trimester) The growth ___ slows and the fetus becomes less active as it has less room to move about

Answer 37

rate

Question 38

(labor) In the first stage of birth and maturation, the ___ thins and dilates, and the amniotic sac ruptures, releasing its fluids

Answer 38

cervix

Question 39

(labor) During the final stage, the uterus contracts, expelling the placenta and the ___

Answer 39

umbilical cord

Question 40

In ___ (flowering plants), double fertilization occurs - one sperm fertilizes the egg cell, and the other fuses to form the endosperm, which provides nutrients to he developing embryo in the seed

Answer 40

angiosperms

Question 41

Some plants can produce seeds without ___ or reproduce without the production of seeds by asexual reproduction, which gives rise to individuals genetically identical to the parent

Answer 41

fertilization

Question 42

In the alternation of generations life cycle, plants can fluctuate between asexual diploid and sexual haploid stages, known as the ___ and gametophyte generations, respectively

Answer 42

sporophyte

Question 43

The ___ sporophyte produces haploid spores via meiosis, which matures into haploid gametophyte

Answer 43

diploid

Question 44

The ___ gametophyte goes on to produce gametes via mitosis

Answer 44

haploid

Question 45

The ___ from mitosis then fuse to produce a zygote

Answer 45

gametes

Question 46

``` The embryo (from the zygote dividing mitotically) has the following parts: ___: precursor of the upper stem and leaves ```

Answer 46

epicotyl

Question 47

Plant embryo Cotyledons: ___ leaves Hypocotyl: the lower stem and root Endosperm: feeds the embryo in angiosperms Seed coat: develops from the outer covering of the ovule

Answer 47

seed

Question 48

___ is the process of a seed sprouting into a seedling (young plant)

Answer 48

germination

Question 49

The ___ is involved in plant development, it is found in the tips of roots and stems

Answer 49

apical meristem

Question 50

The ___ or cambium is located between the xylem and phloem

Answer 50

lateral meristem