Development

Question 1

Development

Answer 1

The process in which a multicellular
organism undergoes a series of progressive changes that
characterizes its life cycle

Question 2

embryo

Answer 2

a plant or animal in its earliest stages

can be protected in a seed, an egg shell, or a
uterus.

Question 3

Four processes of development

Answer 3

Determination
differentiation
morphogenesis
growth

Question 4

Determination

Answer 4

sets the fate of the cell

Question 5

differentiation

Answer 5

process by which different types

of cells arise

Question 6

morphogenesis

Answer 6

organization and spatial
distribution of differentiated cells to create shapes

involves differential gene expression and can occur
in several ways:

occurs in several ways
 Cell division
• Cell expansion (in plant development)
• Cell movements are important in animal
• Apoptosis (programmed cell death) is essential in organ development

Question 7

growth

Answer 7

increase in body size by cell division and
cell expansion

occurs by increasing the number of cells or enlargement of
existing cells.

Question 8

As development proceeds, the potential of cells becomes

Answer 8

more restricted

Question 9

cell fate is influenced by

Answer 9

the extracellular environment, as well as

changes in gene expression.

Question 10

Determination and differentiation occur because of

Answer 10

differential

gene expression.

Question 11

transcriptional controls

Answer 11

Major controls of gene expression in differentiation

Question 12

embryonic stem cells

Answer 12

Early animal embryonic cells have totipotency.

Each cell can develop into a complete embryo.

Question 13

pluripotent

Answer 13

Cells of the blastula or blastocyst are more
“determined” and cannot form a complete
embryo

Question 14

induced pluripotent stem cells

Answer 14

from adult
tissue is now the way stem-cell research is
heading.

Question 15

Fertilization does several things

Answer 15

Blocks entry of additional sperm
•Stimulates ion flux across membrane
•Changes pH of the egg
•Increases egg metabolism and protein synthesis
•Initiates cell division
•Sperm contributes haploid DNA
•Sperm contributes a centriole (not in all species)

Question 16

in mammals cleavage is

Answer 16

rotational

First cell division is
parallel to the
animal–vegetal
axis—yields two
blastomeres.

In second division two
blastomeres divide
at right angles to
each other— one is
parallel to the axis
and the other is
perpendicular to it.

Question 17

mammalian cleavage is

Answer 17

slow and asynchronous.

When the zygote reaches eight cells, the blastomeres change shape to
maximize contact with one another

Question 18

When a blastula reaches 16 to 32 cells, it divides into two groups:

Answer 18

• Inner cell mass—becomes the embryo
• Trophoblast—a sac that forms from the outer cells. Its cells secrete fluid and
create the blastocoel, with the inner cell mass at one end

Embryo is now called a blastocyst.

Question 19

implantation

Answer 19

occurs when
the trophoblast adheres
to the endometrium, or
uterine lining.

Question 20

ectopic or tubal pregnancy

Answer 20

Early implantation that

occurs in the oviduct

Question 21

specific blastomere cells

Answer 21

*cells that are part of the blastula

undergo development into
the specific tissues and
organs.

Question 22

fate maps

Answer 22

identify which cells
in the blastula will become
the particular tissues and
organs

Question 23

ectoderm

Answer 23

outer germ layer
forms epidermal layer of the skin
becomes the nervous system,
the eyes and ears, and the skin

Question 24

neural ectoderm

Answer 24

midline

will form the nervous system

Question 25

gray crescent

Answer 25

site where major cell movement will begin

created by rotation

Question 26

endoderm

Answer 26

innermost layer

will form the lining of the gut, liver, lungs digestory and respiratory tracts

Question 27

mesoderm

Answer 27

middle layer
contains cells that migrate
between the other layers
forms muscle, bone, kidneys, blood vessels, gonads, and connective tissues

Question 28

gastrulation

Answer 28

blastula is transformed into an embryo rthrough movement of cells

Question 29

what occurs after gastrulation

Answer 29

the embryo has multiple tissue layers (ectoderm,

mesoderm, & endoderm) and distinct body axes.

Question 30

process of gastrulation

Answer 30

In frogs, gastrulation begins when bottle cells form in the gray
crescent and become cells of the mesoderm layer.

The process of involution occurs as bottle cells move inward and
create the dorsal lip.

• Convergent extension occurs when cells fated to be mesoderm
elongate as they move, but also intercalate (move in between).

• Cells fated to be ectoderm from the animal hemisphere move toward
the site of involution, a process called epiboly

Vegetal pole bulges inward, invaginates; cells fated to become
endoderm form the archenteron, or gut.

At end of gastrulation embryo has dorsal-ventral and
anterior-posterior organization. Three germ layers
form:

Question 31

cell fate

Answer 31

Type of cell it will ultimately
become; a function of differential gene
expression and morphogenesis.